2022/08/24 更新

写真a

シンボリ アツキ
新堀 淳樹
SHINBORI Atsuki
所属
宇宙地球環境研究所 基盤研究部門 電磁気圏研究部 特任助教
職名
特任助教

学位 1

  1. 博士 (理学) ( 2006年3月   東北大学 ) 

研究キーワード 4

  1. プラズマ圏

  2. 磁気嵐

  3. 電離圏

  4. 全電子数

研究分野 2

  1. 自然科学一般 / 宇宙惑星科学

  2. 自然科学一般 / 宇宙惑星科学

現在の研究課題とSDGs 1

  1. 全球全電子数データ解析に基づく磁気嵐時におけるプラズマ圏・電離圏変動研究

経歴 7

  1. 名古屋大学宇宙地球環境研究所電磁圏研究部   電磁圏研究部   特任助教

    2017年4月 - 現在

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    国名:日本国

  2. 名古屋大学宇宙地球環境研究所   電磁圏研究部   研究員

    2016年11月 - 2017年3月

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    国名:日本国

  3. 京都大学生存圏研究所   学際萌芽研究センター   ミッション専攻研究員

    2015年4月 - 2016年10月

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    国名:日本国

  4. 京都大学生存圏研究所   大気圏精測診断分野   研究員

    2010年4月 - 2015年3月

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    国名:日本国

  5. 名古屋大学太陽地球環境研究所   総合解析部門   研究員

    2009年5月 - 2010年3月

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    国名:日本国

  6. 名古屋大学太陽地球環境研究所   総合解析部門   研究員

    2009年4月

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    国名:日本国

  7. 名古屋大学太陽地球環境研究所   総合解析部門   日本学術振興会特別研究員(PD)

    2006年4月 - 2009年3月

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    国名:日本国

▼全件表示

学歴 2

  1. 東北大学   理学研究科   地球物理学

    - 2006年3月

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    国名: 日本国

  2. 東北大学   理学部   宇宙地球物理学科

    1997年4月 - 2001年3月

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    国名: 日本国

所属学協会 3

  1. 日本地球惑星科学連合

  2. 米国地球物理学連合

  3. 地球電磁気・地球惑星圏学会

 

論文 107

  1. Geomagnetic conjugacy of plasma bubbles extending to mid-latitudes during a geomagnetic storm on March 1, 2013 査読有り

    Sori T., Otsuka Y., Shinbori A., Nishioka M., Perwitasari S.

    Earth, Planets and Space   74 巻 ( 1 )   2022年12月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Earth, Planets and Space  

    This study, for the first time, reports the geomagnetically conjugate structure of a plasma bubble extending to the mid-latitudes and the asymmetrical structure of the decay of the plasma bubble during a geomagnetic storm. We investigated the temporal and spatial variations of plasma bubbles in the Asian sector during a geomagnetic storm on March 1, 2013, using Global Navigation Satellite System-total electron content data with high spatiotemporal resolutions. The first important point of our data analysis results is that the plasma bubble extended from the equator to the mid-latitudes with geomagnetic conjugacy along the magnetic field lines. The total electron content data showed that the plasma bubbles appeared in the equatorial regions near 150° E after sunset during the main phase of the geomagnetic storm. From ionosonde data over both Japan and Australia, they suggest that a large eastward electric field existed in the Asian sector. Finally, the plasma bubbles extended up to the mid-latitudes (~ 43° geomagnetic latitude) in both hemispheres, maintaining geomagnetic conjugacy. The second point is that the mid-latitude plasma bubble disappeared 1–2 h earlier in the northern hemisphere than in the southern hemisphere at close to midnight. In the northern hemisphere, the ionospheric virtual height decreased near midnight, followed by a rapid decrease in the total electron content and a rapid increase in the ionospheric virtual height. These results imply that the mid-latitude plasma bubble disappeared as the background plasma density decreased after midnight due to the recombination resulting from the descent of the F layer. Therefore, we can conclude that mid-latitude plasma bubbles can be asymmetric between the northern and southern hemispheres because of the rapid decay of plasma bubbles in one of the hemispheres. Graphical Abstract: [Figure not available: see fulltext.]

    DOI: 10.1186/s40623-022-01682-7

    Scopus

  2. Electromagnetic conjugacy of ionospheric disturbances after the 2022 Hunga Tonga-Hunga Ha'apai volcanic eruption as seen in GNSS-TEC and SuperDARN Hokkaido pair of radars observations 査読有り

    Shinbori Atsuki, Otsuka Yuichi, Sori Takuya, Nishioka Michi, Perwitasari Septi, Tsuda Takuo, Nishitani Nozomu

    EARTH PLANETS AND SPACE   74 巻 ( 1 )   2022年7月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Earth, Planets and Space  

    To elucidate the characteristics of electromagnetic conjugacy of traveling ionospheric disturbances just after the 15 January 2022 Hunga Tonga-Hunga Ha’apai volcanic eruption, we analyze Global Navigation Satellite System-total electron content data and ionospheric plasma velocity data obtained from the Super Dual Auroral Radar Network Hokkaido pair of radars. Further, we use thermal infrared grid data with high spatial resolution observed by the Himawari 8 satellite to identify lower atmospheric disturbances associated with surface air pressure waves propagating as a Lamb mode. After 07:30 UT on 15 January, two distinct traveling ionospheric disturbances propagating in the westward direction appeared in the Japanese sector with the same structure as those at magnetically conjugate points in the Southern Hemisphere. Corresponding to these traveling ionospheric disturbances with their large amplitude of 0.5 – 1.1 × 1016 el/m2 observed in the Southern Hemisphere, the plasma flow direction in the F region changed from southward to northward. At this time, the magnetically conjugate points in the Southern Hemisphere were located in the sunlit region at a height of 105 km. The amplitude and period of the plasma flow variation are ~ 100–110 m/s and ~ 36–38 min, respectively. From the plasma flow perturbation, a zonal electric field is estimated as ~ 2.8–3.1 mV/m. Further, there is a phase difference of ~ 10–12 min between the total electron content and plasma flow perturbations. This result suggests that the external electric field variation generates the traveling ionospheric disturbances observed in both Southern and Northern Hemispheres. The origin of the external electric field is an E-region dynamo driven by the neutral wind oscillation associated with atmospheric acoustic waves and gravity waves. Finally, the electric field propagates to the F region and magnetically conjugate ionosphere along magnetic field lines with the local Alfven speed, which is much faster than that of Lamb mode waves. From these observational facts, it can be concluded that the E-region dynamo electric field produced in the sunlit Southern Hemisphere is a main cause of the two distinct traveling ionospheric disturbances appearing over Japan before the arrival of the air pressure disturbances. Graphical Abstract: [Figure not available: see fulltext.]

    DOI: 10.1186/s40623-022-01665-8

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  3. A confirmation of vertical acoustic resonance and field-aligned current generation just after the 2022 Hunga Tonga Hunga Ha'apai volcanic eruption 査読有り

    Iyemori Toshihiko, Nishioka Michi, Otsuka Yuichi, Shinbori Atsuki

    EARTH PLANETS AND SPACE   74 巻 ( 1 )   2022年6月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Earth, Planets and Space  

    A strong volcanic eruption caused a clear vertical acoustic resonance between the sea surface and the thermosphere. Its effects are observed as geomagnetic and GPS-TEC oscillations near the volcano and its geomagnetic conjugate area. The geomagnetic oscillations are observed at Apia and Honolulu geomagnetic observatories with amplitude of about 2 nT and 0.2 nT, respectively. The volcanic eruption started around 04:14 UT on January 15, 2022. The oscillations appeared at 04:21UT at Apia, Samoa, only about 7 min after the start of eruption. Because the distance between the volcano and Apia is about 841 km, it takes about 40 min for a sound wave to propagate from the volcano to Apia. Therefore, it is more plausible to assume that the magnetic oscillation observed at Apia about 7 min after the eruption is caused by the sound waves propagated vertically upward to the ionosphere and generated an electric current. The coherent appearance of geomagnetic oscillation at Honolulu located near the geomagnetic conjugate point of the volcano strongly support the idea that the ionospheric current generated over the volcano diverted as a field-aligned current which flew to the opposite hemisphere and caused the geomagnetic oscillation at Honolulu. The earliest start of GPS-TEC oscillation was around 04:15UT near the volcanic eruption, and it was around 04:20 UT at KOKV station in Hawaii. The time-lag of the TEC variations between Samoa and Hawaii obtained by a cross-correlation analysis is 4.5 min or 8.5 min. These time differences are much smaller than the travel time of the seismic waves from the volcano to Hawaii islands. Therefore, it is suggested that the electric field transmitted along geomagnetic field caused the TEC variation observed over Hawaii Islands. A sawtooth waveform of geomagnetic oscillation observed at Apia and Honolulu is analyzed and a possible generation mechanism is discussed. Graphical Abstract: [Figure not available: see fulltext.]

    DOI: 10.1186/s40623-022-01653-y

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  4. Advanced tools for guiding data-led research processes of Upper-Atmospheric phenomena 査読有り

    Tanaka Yoshimasa, Umemura Norio, Abe Shuji, Shinbori Atsuki, UeNo Satoru

    GEOSCIENCE DATA JOURNAL     2022年6月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Geoscience Data Journal  

    This paper presents tools that help researchers implement the processes of data-led studies of upper-atmospheric phenomena. These tools were developed as a part of the activities of the Inter-university Upper atmosphere Global Observation NETwork (IUGONET) of Japan, which is a project to develop infrastructure for upper-atmospheric research data. This paper focuses on the data service named IUGONET Type-A, which was launched in October 2016 and has since evolved. In addition to being a conventional metadata catalogue, it has many other useful functions: an easy cross-searching system, a quick-look data-plotting procedure, an interactive data visualization system named UDAS web, and strong linkage with analysis software. Users can pick up relevant data from a huge number of data sets using either lists categorized by instruments/projects, observed regions and special campaigns or a world map of observatories. Users can quickly find the time, location and nature of phenomena that occurred by comparing the quick-look plots of various data displayed by the browser. UDAS web allows researchers to interactively create stacked plots of various data types that can facilitate the understanding of the relationships among phenomena observed in different regions. Furthermore, it presents a command list for software dedicated to data analysis that can smoothly lead users to perform detailed analyses. IUGONET Type-A provides a one-stop data service that can assist users in searching, examining and comprehending data for advanced analysis. It is also capable of handling old data, including analogue data and written paper documents. Thus, it will provide useful support for innovative interdisciplinary scientific research on solar–terrestrial phenomena.

    DOI: 10.1002/gdj3.170

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  5. On the Role of E-F Region Coupling in the Generation of Nighttime MSTIDs During Summer and Equinox: Case Studies Over Northern Germany 査読有り

    Sivakandan Mani, Martinis Carlos, Otsuka Yuichi, Chau Jorge L., Norrell Jessica, Mielich Jens, Conte J. Federico, Stolle Claudia, Rodriguez-Zuluaga J., Shinbori Atsuki, Nishioka Michi, Tsugawa Takuya

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   127 巻 ( 5 )   2022年5月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    Simultaneous observations from a 630 nm all-sky airglow imager, GNSS-TEC receivers, and an ionosonde are used to investigate the role of E- and F-region coupling on the generation of medium-scale traveling ionospheric disturbances (MSTIDs). The primary observations are OI 630 nm airglow images taken by an all-sky imager in Kühlungsborn (54.07°N; 11.46°E, 53.79°N Mlat.), a site in northern Germany. Out of 226 nights of observations, MSTIDs were found only in 18 nights, demonstrating the low occurrence rate over Kühlungsborn. We focused on four MSTIDs events: two during the vernal equinox and two during summer. Coincident measurements of detrended GNSS-TEC supported the presence of MSTIDs during the selected events, and simultaneous observations from the ionosonde in Juliusruh (54.60°N, 13.4°E, 54.02°N Mlat.) showed sporadic-E (Es) layer and spread-F activity in the E- and F-region, respectively. We observed the onset of the observed MSTIDs to be around the 15°–20°E longitude and 60–45°N latitude belts. Additionally, we found that in each case, the onset of MSTIDs coincides with the presence of an Es layer with sporadic-E trace is observed (foEs) exceeding 4 MHz. This suggests that an Es layer with foEs ≥ 4MHz was a source of the generation of these MSTIDs. Altitude of the Es layer could be another important factor in generating MSTIDs. The Es layer should exist at an altitude where Hall conductivity is large, as happened in the present study.

    DOI: 10.1029/2021JA030159

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    Scopus

  6. Generation Mechanisms of Plasma Density Irregularity in the Equatorial Ionosphere During a Geomagnetic Storm on 21-22 December 2014 査読有り

    Sori T., Shinbori A., Otsuka Y., Tsugawa T., Nishioka M., Yoshikawa A.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   127 巻 ( 5 )   2022年5月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    The equatorial ionosphere endured plasma density irregularities during a geomagnetic storm on 21–22 December 2014. To understand the underlying mechanism, we analyzed the rate of the total electron content change (ROTI) data obtained from a global navigation satellite system, along with solar wind, interplanetary magnetic field (IMF), geomagnetic indices, Jicamarca incoherent scatter radar, and magnetometer data. The results indicate that the ROTI enhancement related to plasma density irregularities (plasma bubbles) occurred three times in the equatorial and low latitude regions of the American sector during the geomagnetic storm. The first, second, and third enhancements which have a longitudinal extent of ∼20° appeared in the post-sunset, pre-midnight, and post-midnight sectors, respectively. The second enhancement occurred during the recovery phase of the storm-time substorm even though the IMF remained southward. During this period, the direction of the dayside equatorial electrojet (EEJ) changed from eastward to westward, while the nightside upward plasma velocity at Jicamarca increased to 28.8 m/s. The response of the EEJ and upward ion drift implies that the westward and eastward electric fields were intensified on the dayside and nightside, respectively. Therefore, these results suggest that an over-shielding electric field penetrates the dayside/nightside equator simultaneously in association with a substorm recovery phase, and that the electric field generates plasma bubbles by the Rayleigh-Taylor instability mechanism. Plasma bubbles induced by the penetration of an over-shielding electric field due to substorm activity have not previously been reported.

    DOI: 10.1029/2021JA030240

    Web of Science

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  7. Propagation Direction Analyses of Medium-Scale Traveling Ionospheric Disturbances Observed Over North America With GPS-TEC Perturbation Maps by Three-Dimensional Spectral Analysis Method 査読有り

    Perwitasari Septi, Nakamura Takuji, Tsugawa Takuya, Nishioka Michi, Tomikawa Yoshihiro, Ejiri Mitsumu K., Kogure Masaru, Otsuka Yuichi, Shinbori Atsuki, Jin Hidekatsu, Tao Chihiro

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   127 巻 ( 1 )   2022年1月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    We applied a novel three-dimensional spectral analysis method to GPS-TEC perturbation (GPS-TECP) maps to study the propagation direction of daytime and nighttime medium-scale traveling ionospheric disturbances (MSTIDs) over North America. By this method, we can automatically calculate the phase velocity spectrum and directionality of MSTIDs. We focused on the periods of high MSTIDs occurrence, namely, June–July 2006 and November–December 2006, to study nighttime and daytime MSTIDs. We divided North America into the west (100°–130°W, 25°–55°N) and east (70°–100°W, 25°–55°N) parts. Our results show that both daytime and nighttime MSTID propagations exhibit strong longitudinal variations as a function of local time and day-to-day variations. The power peaks of daytime MSTIDs are from 10:00–16:00 LT in the west part and 10:00–14:00 LT in the east part. The predominant propagation directions of daytime MSTIDs are southward (southeastward) in the west (east). The daytime local time variations demonstrate that the MSTIDs display directional change in the west part; however, a similar directional change is not very pronounced in the east part. The local time variations of nighttime MSTIDs shows the power peaks from 22:00–02:00 LT in the west and 20:00–00:00 LT in the east. We found that the predominant propagation direction in the west part is westward with a wider azimuthal band (∼210°–300°) than the east part (∼210°–240°). By comparing nighttime propagation directions between the western and eastern parts, we reached the conclusion that the magnetic declination angle affects the propagation direction.

    DOI: 10.1029/2020JA028791

    Web of Science

    Scopus

  8. Statistical Behavior of Large-Scale Ionospheric Disturbances From High Latitudes to Mid-Latitudes During Geomagnetic Storms Using 20-yr GNSS-TEC Data: Dependence on Season and Storm Intensity 査読有り

    Shinbori Atsuki, Otsuka Yuichi, Sori Takuya, Tsugawa Takuya, Nishioka Michi

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   127 巻 ( 1 )   2022年1月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    To establish the statistical behavior of ionospheric TEC variations from high latitudes to mid-latitudes during the main and recovery phases of geomagnetic storms, we conducted a superposed epoch analysis of interplanetary magnetic field, solar wind, geomagnetic indices (AE and SYM-H), and global navigation satellite system (GNSS)-total electron content (TEC) data for 20 yr (2000–2019). In this study, we identify 663 geomagnetic storm events with the minimum SYM-H value of less than −40 nT and investigate the characteristics of the TEC variations for the weak (−60 ≤ SYM-Hmin < −40 nT), moderate (−100 ≤ SYM-Hmin < −60 nT), and strong (−150 ≤ SYM-Hmin < −100 nT) geomagnetic storms. The main results obtained from the present study are as follows: (a) The TEC enhancements related to the tongue of ionization (TOI), auroral oval, and storm-enhanced density (SED) plume are more dominant in winter than in summer during the main phase of geomagnetic storms. (b) The structure of the mid-latitude trough in the nighttime sector becomes unclear in winter. (c) The TEC depletion at auroral and mid-latitudes (40°–70° GMLAT: geomagnetic latitude) starts to appear in the morning sector (8–10 hr GMLT: geomagnetic local time) during the main phase of geomagnetic storms and the decreased region extends in the lower latitude and GMLT directions with time. The negative storm activity tends to be enhanced significantly as the storm intensity becomes larger. The activity of the TEC depletion is dominant in summer than in winter, which is agreement with the classical ionospheric storm scenario.

    DOI: 10.1029/2021JA029687

    Web of Science

    Scopus

  9. Propagation Mechanism of Medium Wave Broadcasting Waves Observed by the Arase Satellite: Hectometric Line Spectra 査読有り

    Hashimoto Kozo, Shinbori Atsuki, Otsuka Yuichi, Tsuchiya Fuminori, Kumamoto Atsushi, Kasahara Yoshiya, Matsuoka Ayako, Nagano Isamu, Miyoshi Yoshizumi, Yokoyama Tatsuhiro

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   126 巻 ( 11 )   2021年11月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    A new type of terrestrial line spectra found by the Arase satellite was reported in 2018. These spectra are called “hectometric line spectra (HLS)”. They primarily consist of constant frequency narrowband components at frequencies between 525 kHz and 1,700 kHz, which originate and are sometimes amplified from AM broadcasting waves. In addition to these, other generated emissions are observed. Entrances and the mode conversion of the AM broadcasting waves into the equatorial and low-latitude ionosphere with plasma density depletion called plasma bubbles are observed. Electron density profiles and equatorial plasma bubbles are examined through Global Positioning System (GPS)-Total electron content (TEC) analyses. As a result, the Arase satellite which observed the HLS passed through the TEC depression region near the equatorial ionosphere associated with plasma bubbles. The scenario based on the mode conversion of the L-O mode to the Z mode and vice versa was confirmed with observations and GPS-TEC analyses. Another entrance when foF2 estimated from TEC is lower than 1,000 kHz instead of a plasma bubble is also found. No mode conversion is necessary, then.

    DOI: 10.1029/2021JA029813

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  10. Field-Aligned Electron Density Distribution of the Inner Magnetosphere Inferred From Coordinated Observations of Arase and Van Allen Probes 査読有り

    Obana Yuki, Miyashita Yukinaga, Maruyama Naomi, Shinbori Atsuki, Nose Masahito, Shoji Masafumi, Kumamoto Atsushi, Tsuchiya Fuminori, Matsuda Shoya, Matsuoka Ayako, Kasahara Yoshiya, Miyoshi Yoshizumi, Shinohara Iku, Kurth William S., Smith Charles W., MacDowall Robert J.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   126 巻 ( 10 )   2021年10月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    The Radiation Belt Storm Probes (RBSP) and the Arase satellites have different inclinations and sometimes they fly both near the equator and off the equator on the same magnetic field line simultaneously. Such conjunction events give us opportunities to compare the electron density at different latitudes. In this study, we analyzed the plasma waves observed by Arase and RBSP during the three conjunction events during and after the September 7, 2017 storm. The electron number density at the satellite positions was estimated from frequencies of the Upper Hybrid Resonance emissions obtained by the High Frequency Analyzer of the Plasma Wave Experiment onboard the Arase and the Waves instrument onboard the RBSP, respectively. During the three conjunction events, the satellites passed through the plume, inner trough (the narrow region with low electron density between the main body of the plasmasphere and the plume), plasmatrough with variable electron density, and partially refilled plasmasphere. The power-law index m for the inner trough and plume was inferred to be 4–7 and ∼0, respectively. This is interpreted to mean that the trough was close to collisionless and the plume was relatively near diffusive equilibrium. In the plasmatrough with the varying density, both the high-density and low-density regions had m ∼ 0. The low-density portion of this region may have a different origin from the inner trough, because of the different m indices. For the partially refilled plasmasphere in the storm recovery phase, the power-law index m showed negative values, meaning that the density in the equatorial plane was higher than at higher latitudes.

    DOI: 10.1029/2020JA029073

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  11. Plasma depletions lasting into daytime during the recovery phase of a geomagnetic storm in May 2017: Analysis and simulation of GPS total electron content observations 査読有り

    Otsuka Yuichi, Shinbori Atsuki, Sori Takuya, Tsugawa Takuya, Nishioka Michi, Huba Joseph D.

    EARTH AND PLANETARY PHYSICS   5 巻 ( 5 ) 頁: 427 - 434   2021年9月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Earth and Planetary Physics  

    This paper reports that plasma density depletions appearing at middle latitudes near sunrise survived until afternoon on 29 May 2017 during the recovery phase of a geomagnetic storm. By analyzing GPS data collected in Japan, we investigate temporal variations in the horizontal two-dimensional distribution of total electron content (TEC) during the geomagnetic storm. The SYM-H index reached −142 nT around 08 UT on 28 May 2017. TEC depletions extending up to approximately 38°N along the meridional direction appeared over Japan around 05 LT (LT = UT + 9 hours) on 29 May 2017, when TEC rapidly increased at sunrise due to the solar extreme ultraviolet (EUV) radiation. The TEC depletions appeared sequentially over Japan for approximately 8 hours in sunlit conditions. At 06 LT on 29 May, when the plasma depletions first appeared over Japan, the background TEC was enhanced to approximately 17 TECU, and then decreased to approximately 80% of the TEC typical of magnetically quiet conditions. We conclude that this temporal variation of background plasma density in the ionosphere was responsible for the persistence of these plasma depletions for so long in daytime. By using the Naval Research Laboratory: Sami2 is Another Model of the Ionosphere (SAMI2), we have evaluated how plasma production and ambipolar diffusion along the magnetic field may affect the rate of plasma depletion disappearance. Simulation shows that the plasma density increases at the time of plasma depletion appearance; subsequent decreases in the plasma density appear to be responsible for the long-lasting persistence of plasma depletions during daytime. The plasma density depletion in the top side ionosphere is not filled by the plasma generated by the solar EUV productions because plasma production occurs mainly at the bottom side of the ionosphere.

    DOI: 10.26464/epp2021046

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  12. Evidence for the In-Situ Generation of Plasma Depletion Structures Over the Transition Region of Geomagnetic Low-Mid Latitude 査読有り

    Sivakandan M., Mondal S., Sarkhel S., Chakrabarty D., Krishna M. V. Sunil, Upadhayaya A. K., Shinbori A., Sori T., Kannaujiya S., Ray P. K. Champati

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   126 巻 ( 9 )   2021年9月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    On a geomagnetic quiet night of October 29, 2018, we captured an observational evidence of the onset of dark band structures within the field-of-view of an all-sky airglow imager operating at 630.0 nm over a geomagnetic low-mid latitude transition region, Hanle, Leh Ladakh. Simultaneous ionosonde observations over New Delhi shows the occurrence of spread-F in the ionograms. Additionally, virtual and peak height indicate vertical upliftment in the F layer altitude and reduction in the ionospheric peak frequency were also observed when the dark band pass through the ionosonde location. All these results confirmed that the observed depletions are indeed associated with ionospheric F region plasma irregularities. The rate of total electron content index (ROTI) indicates the absence of plasma bubble activities over the equatorial/low latitude region which confirms that the observed event is a mid-latitude plasma depletion. Our calculations reveal that the growth time of the plasma depletion is ∼2 h if one considers only the Perkins instability mechanism. This is not consistent with the present observations as the plasma depletion developed within ∼25 min. By invoking possible Es layer instabilities and associated E-F region coupling, we show that the growth rate increases roughly by an order of magnitude. This strongly suggests that the Cosgrove and Tsunoda mechanism may be simultaneously operational in this case. Furthermore, it is also suggested that reduced F region flux-tube integrated conductivity in the southern part of onset region created conducive background conditions for the growth of the plasma depletion on this night.

    DOI: 10.1029/2020JA028837

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  13. Relationship Between the Locations of the Midlatitude Trough and Plasmapause Using GNSS-TEC and Arase Satellite Observation Data 査読有り

    Shinbori Atsuki, Otsuka Yuichi, Tsugawa Takuya, Nishioka Michi, Kumamoto Atsushi, Tsuchiya Fuminori, Matsuda Shoya, Kasahara Yoshiya, Matsuoka Ayako

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   126 巻 ( 5 )   2021年5月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    Relationship between the locations of the midlatitude trough minimum in the ionosphere and plasmapause in the inner magnetosphere has been statistically investigated using global navigation satellite system (GNSS)-total electron content (TEC) and electron density data obtained from the Arase satellite from March 23, 2017 to May 31, 2020. In this analysis, we identify the midlatitude trough minimum as a minimum value of GNSS-TEC at subauroral and midlatitude regions, and determine the plasmapause as an electron density decrease by a factor of 5 or more within ΔL < 0.5 in the inner magnetosphere. As a result, the plasmapause does not always coincide with the midlatitude trough minimum in all magnetic local time (MLT) sectors under all geomagnetic conditions. During the geomagnetically quiet periods, the midlatitude trough minimum is located at higher and lower geomagnetic latitudes (GMLATs) of the plasmapause in the MLT ranges of 5–21 and 21–5 h, respectively. This implies that both the features could not be on the same magnetic field line. On the other hand, during the storm main phase, the midlatitude trough minimum and plasmapause move toward a low-latitude region with day-night and dawn-dusk asymmetries and the correlation becomes highest, compared with that under other geomagnetic conditions. Especially, both the features mapped on the ionosphere at a height of 300 km exist near GMLAT in the afternoon-midnight sectors. This suggests that the midlatitude trough and plasmapause are formed at almost the same location due to an enhanced subauroral polarization stream during the storm main phase.

    DOI: 10.1029/2020JA028943

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  14. The Occurrence Feature of Plasma Bubbles in the Equatorial to Midlatitude Ionosphere During Geomagnetic Storms Using Long-Term GNSS-TEC Data 査読有り

    Sori T., Shinbori A., Otsuka Y., Tsugawa T., Nishioka M.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   126 巻 ( 5 )   2021年5月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    We performed a superposed epoch analysis of solar wind, interplanetary magnetic field, geomagnetic index, and the rate of total electron content (TEC) index (ROTI) derived from global navigation satellite system-TEC data during 652 geomagnetic storm events (minimum SYM-H < −40 nT), to clarify the occurrence features and causes of storm-time plasma bubbles in the equatorial to mid-latitude ionosphere. In this analysis, we defined the time of the SYM-H minimum as the zero epoch. As a result, the ROTI enhancement started at the duskside magnetic equator and expanded to higher latitudes during the main phase. Approximately 1 h after the onset of the recovery phase, the ROTI values at the magnetic equator in the dusk-to-midnight sectors decreased while those in the dawn sector increased. This situation persisted for at least 12 h. The ratio of the ROTI during the main phase to that during the quiet period in the dusk sector is the largest in May–July. The ratio of the ROTI during the recovery phase decreased during dusk with increasing solar activity. Considering the requirement of the Rayleigh-Taylor instability, the difference in the magnetic local time of the ROTI signature, between the main and recovery phases, can be explained by a local time distribution of storm-time electric fields associated with a prompt penetration electric field and disturbance dynamo. This implies that the occurrence feature of the plasma bubble is different from that during quiet times when the input of solar wind energy to the magnetosphere and ionosphere increases significantly.

    DOI: 10.1029/2020JA029010

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  15. Simultaneous Observation of Two Isolated Proton Auroras at Subauroral Latitudes by a Highly Sensitive All-Sky Camera and Van Allen Probes 査読有り

    Nakamura Kohki, Shiokawa Kazuo, Otsuka Yuichi, Shinbori Atsuki, Miyoshi Yoshizumi, Connors Martin, Spence Harlan, Reeves Geoff, Funsten Herbert O., MacDowall Robert, Smith Charles, Wygant John, Bonnell John

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   126 巻 ( 5 )   2021年5月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    Isolated proton auroras (IPAs) appearing at subauroral latitudes are generated by energetic protons precipitating from the magnetosphere through interaction with electromagnetic ion cyclotron (EMIC) waves. An IPA thus indicates the spatial scale and temporal variation of wave-particle interactions in the magnetosphere. In this study, a unique event of simultaneous ground and magnetospheric satellite observations of two IPAs were conducted on March 16, 2015, using an all-sky imager at Athabasca, Canada and Van Allen Probes. The Van Allen Probes observed two isolated EMIC waves with frequencies of ∼1 and 0.4 Hz at L ≈ 5.0 when the satellite footprint crossed over the two IPAs. This suggests that the IPAs were caused by localized EMIC waves. Proton flux at 5–20 keV increased locally when the EMIC waves appeared. Electron flux at energies below ∼500 eV also increased. Temperature anisotropy of the energetic protons was estimated at 1.5–2.5 over a wide L-value range of 3.0–5.2. Electron density gradually decreased from L = 3.5 to 5.4, suggesting that the EMIC wave at L ≈ 5.0 was located in the gradual plasmapause. From these observations, we conclude that the localized IPAs and associated EMIC waves took place because of localized enhancement of energetic proton flux and plasma density structure near the plasmapause. The magnetic field observed by the satellite showed small variation during the wave observation, indicating that the IPAs were accompanied by the weak field-aligned current.

    DOI: 10.1029/2020JA029078

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  16. Model-based reproduction and validation of the total spectra of a solar flare and their impact on the global environment at the X9.3 event of September 6, 2017 査読有り

    Watanabe Kyoko, Jin Hidekatsu, Nishimoto Shohei, Imada Shinsuke, Kawai Toshiki, Kawate Tomoko, Otsuka Yuichi, Shinbori Atsuki, Tsugawa Takuya, Nishioka Michi

    EARTH PLANETS AND SPACE   73 巻 ( 1 )   2021年4月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Earth, Planets and Space  

    We attempted to reproduce the total electron content (TEC) variation in the Earth's atmosphere from the temporal variation of the solar flare spectrum of the X9.3 flare on September 6, 2017. The flare spectrum from the Flare Irradiance Spectral Model (FISM), and the flare spectrum from the 1D hydrodynamic model, which considers the physics of plasma in the flare loop, are used in the GAIA model, which is a simulation model of the Earth's whole atmosphere and ionosphere, to calculate the TEC difference. We then compared these results with the observed TEC. When we used the FISM flare spectrum, the difference in TEC from the background was in a good agreement with the observation. However, when the flare spectrum of the 1D-hydrodynamic model was used, the result varied depending on the presence or absence of the background. This difference depending on the models is considered to represent which extreme ultraviolet (EUV) radiation is primarily responsible for increasing TEC. From the flare spectrum obtained from these models and the calculation result of TEC fluctuation using GAIA, it is considered that the enhancement in EUV emission by approximately 15–35 nm mainly contributes in increasing TEC rather than that of X-ray emission, which is thought to be mainly responsible for sudden ionospheric disturbance. In addition, from the altitude/wavelength distribution of the ionization rate of Earth's atmosphere by GAIA (Ground-to-topside Atmosphere and Ionosphere model for Aeronomy), it was found that EUV radiation of approximately 15–35 nm affects a wide altitude range of 120–300 km, and TEC enhancement is mainly caused by the ionization of nitrogen molecules.[Figure not available: see fulltext.]

    DOI: 10.1186/s40623-021-01376-6

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  17. Multi-Event Analysis of Plasma and Field Variations in Source of Stable Auroral Red (SAR) Arcs in Inner Magnetosphere During Non-Storm-Time Substorms 査読有り

    Inaba Yudai, Shiokawa Kazuo, Oyama Shin-ichiro, Otsuka Yuichi, Connors Martin, Schofield Ian, Miyoshi Yoshizumi, Imajo Shun, Shinbori Atsuki, Gololobov Artem Yu, Kazama Yoichi, Wang Shiang-Yu, Tam Sunny W. Y., Chang Tzu-Fang, Wang Bo-Jhou, Asamura Kazushi, Yokota Shoichiro, Kasahara Satoshi, Keika Kunihiro, Hori Tomoaki, Matsuoka Ayako, Kasahara Yoshiya, Kumamoto Atsushi, Matsuda Shoya, Kasaba Yasumasa, Tsuchiya Fuminori, Shoji Masafumi, Kitahara Masahiro, Nakamura Satoko, Shinohara Iku, Spence Harlan E., Reeves Geoff D., Macdowall Robert J., Smith Charles W., Wygant John R., Bonnell John W.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   126 巻 ( 4 )   2021年4月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    Stable auroral red (SAR) arcs are optical events with dominant 630.0-nm emission caused by low-energy electron heat flux into the topside ionosphere from the inner magnetosphere. SAR arcs are observed at subauroral latitudes and often occur during the recovery phase of magnetic storms and substorms. Past studies concluded that these low-energy electrons were generated in the spatial overlap region between the outer plasmasphere and ring-current ions and suggested that Coulomb collisions between plasmaspheric electrons and ring-current ions are more feasible for the SAR-arc generation mechanism rather than Landau damping by electromagnetic ion cyclotron waves or kinetic Alfvén waves. This work studies three separate SAR-arc events with conjunctions, using all-sky imagers and inner magnetospheric satellites (Arase and Radiation Belt Storm Probes [RBSP]) during non-storm-time substorms on December 19, 2012 (event 1), January 17, 2015 (event 2), and November 4, 2019 (event 3). We evaluated for the first time the heat flux via Coulomb collision using full-energy-range ion data obtained by the satellites. The electron heat fluxes due to Coulomb collisions reached ∼109 eV/cm2/s for events 1 and 2, indicating that Coulomb collisions could have caused the SAR arcs. RBSP-A also observed local enhancements of 7–20-mHz electromagnetic wave power above the SAR arc in event 2. The heat flux for the freshly detached SAR arc in event 3 reached ∼108 eV/cm2/s, which is insufficient to have caused the SAR arc. In event 3, local flux enhancement of electrons (<200 eV) and various electromagnetic waves were observed, these are likely to have caused the freshly detached SAR arc.

    DOI: 10.1029/2020JA029081

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  18. Comparison of seasonal and longitudinal variation of daytime MSTID activity using GPS observation and GAIA simulations 査読有り

    Sivakandan Mani, Otsuka Yuichi, Ghosh Priyanka, Shinagawa Hiroyuki, Shinbori Atsuki, Miyoshi Yasunobu

    EARTH PLANETS AND SPACE   73 巻 ( 1 )   2021年2月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Earth, Planets and Space  

    The total electron content (TEC) data derived from the GAIA (Ground-to-topside model of Atmosphere Ionosphere for Aeronomy) is used to study the seasonal and longitudinal variation of occurrence of medium-scale traveling ionospheric disturbances (MSTIDs) during daytime (09:00–15:00 LT) for the year 2011 at eight locations in northern and southern hemispheres, and the results are compared with ground-based Global Positioning System (GPS)-TEC. To derive TEC variations caused by MSTIDs from the GAIA (GPS) data, we obtained detrended TEC by subtracting 2-h (1-h) running average from the TEC, and calculated standard deviation of the detrended TEC in 2 h (1 h). MSTID activity was defined as a ratio of the standard deviation to the averaged TEC. Both GAIA simulation and GPS observations data show that daytime MSTID activities in the northern and southern hemisphere (NH and SH) are higher in winter than in other seasons. From the GAIA simulation, the amplitude of the meridional wind variations, which could be representative of gravity waves (GWs), shows two peaks in winter and summer. The winter peak in the amplitude of the meridional wind variations coincides with the winter peak of the daytime MSTIDs, indicating that the high GW activity is responsible for the high MSTID activity. On the other hand, the MSTID activity does not increase in summer. This is because the GWs in the thermosphere propagate poleward in summer, and equatorward in winter, and the equatorward-propagating GWs cause large plasma density perturbations compared to the poleward-propagating GWs. Longitudinal variation of daytime MSTID activity in winter is seen in both hemispheres. The MSTID activity during winter in the NH is higher over Japan than USA, and the MSTID activity during winter in the SH is the highest in South America. In a nutshell, GAIA can successfully reproduce the seasonal and longitudinal variation of the daytime MSTIDs. This study confirms that GWs cause the daytime MSTIDs in GAIA and amplitude and propagation direction of the GWs control the noted seasonal variation. GW activities in the middle and lower atmosphere cause the longitudinal variation. [Figure not available: see fulltext.].

    DOI: 10.1186/s40623-021-01369-5

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  19. Solar activity dependence of medium-scale traveling ionospheric disturbances using GPS receivers in Japan 査読有り

    Otsuka Yuichi, Shinbori Atsuki, Tsugawa Takuya, Nishioka Michi

    EARTH PLANETS AND SPACE   73 巻 ( 1 )   2021年1月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Earth, Planets and Space  

    In order to reveal solar activity dependence of the medium-scale traveling ionospheric disturbances (MSTIDs) at midlatitudes, total electron content (TEC) data obtained from a Global Positioning System (GPS) receiver network in Japan during 22 years from 1998 to 2019 were analyzed. We have calculated the detrended TEC by subtracting the 1-h running average from the original TEC data for each satellite and receiver pair, and made two-dimensional TEC maps of the detrended TEC with a spatial resolution of 0.15° × 0.15° in longitude and latitude. We have investigated MSTID activity, defined as δI/ I¯ , where δI and I¯ are standard deviation of the detrended TEC and the average vertical TEC within the area of 133.0°–137.0° E and 33.0°–37.0° N for 1 h, respectively. From each 2-h time series of the detrended TEC data within the same area as the MSTID activity, auto-correlation functions (ACFs) of the detrended TEC were calculated to estimate the horizontal propagation velocity and direction of the MSTIDs. Statistical results of the MSTID activity and propagation direction of MSTIDs were consistent with previous studies and support the idea that daytime MSTIDs could be caused by atmospheric gravity waves, and that nighttime MSTIDs were caused by electro-dynamical forces, such as the Perkins instability. From the current long-term observations, we have found that the nighttime MSTID activity and occurrence rate increased with decreasing solar activity. For the daytime MSTID, the occurrence rate increased with decreasing solar activity, whereas the MSTID activity did not show distinct solar activity dependence. These results suggest that the secondary gravity waves generated by dissipation of the primary gravity waves propagating from below increase under low solar activity conditions. The mean horizontal phase velocity of the MSTIDs during nighttime did not show a distinct solar activity dependence, whereas that during daytime showed an anticorrelation with solar activity. The horizontal phase velocity of the daytime MSTIDs was widely distributed from 40 to 180 m/s under high solar activity conditions, whereas it ranged between 80 and 200 m/s, with a maximum occurrence at 130 m/s under low solar activity conditions, suggesting that gravity waves with low phase velocity could be dissipated by high viscosity in the thermosphere under low solar activity conditions. [Figure not available: see fulltext.]

    DOI: 10.1186/s40623-020-01353-5

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  20. An Ephemeral Red Arc Appeared at 68 degrees MLat at a Pseudo Breakup During Geomagnetically Quiet Conditions 査読有り

    Oyama S., Shinbori A., Ogawa Y., Kellinsalmi M., Raita T., Aikio A., Vanhamaeki H., Shiokawa K., Virtanen I., Cai L., Workayehu A. B., Pedersen M., Kauristie K., Tsuda T. T., Kozelov B., Demekhov A., Yahnin A., Tsuchiya F., Kumamoto A., Kasahara Y., Matsuoka A., Shoji M., Teramoto M., Lester M.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   125 巻 ( 10 )   2020年10月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    Various subauroral optical features have been studied by analyzing data collected during periods of geomagnetic disturbances. Most events have been typically found at geomagnetic latitudes of 45–60°. In this study, however, we present a red arc event found at geomagnetic 68° north (L ≈ 7.1) in the Scandinavian sector during a period of geomagnetically quiet conditions within a short intermission between two high-speed solar wind events. The red arc appeared to coincide with a pseudo breakup at geomagnetic 71–72°N and a rapid equatorward expansion of the polar cap. However, the red arc disappeared in approximately 7 min. Simultaneous measurements with the Swarm A/C satellites indicated the appearance of the red arc at the ionospheric trough minimum and a conspicuous enhancement of the electron temperature, suggesting the generation of the arc by heat flux. Since there are meaningful differences in the red arc features from already-known subauroral optical features such as the stable auroral red (SAR) arc, we considered that the red arc is a new phenomenon. We suggest that the ephemeral red arc may represent the moment of SAR arc birth associated with substorm particle injection, which is generally masked by bright dynamic aurorae.

    DOI: 10.1029/2020JA028468

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  21. Plasma and Field Observations in the Magnetospheric Source Region of a Stable Auroral Red (SAR) Arc by the Arase Satellite on 28 March 2017 査読有り

    Inaba Yudai, Shiokawa Kazuo, Oyama Shin-ichiro, Otsuka Yuichi, Oksanen Arto, Shinbori Atsuki, Gololobov Artem Yu, Miyoshi Yoshizumi, Kazama Yoichi, Wang Shiang-Yu, Tam Sunny W. Y., Chang Tzu-Fang, Wang Bo-Jhou, Yokota Shoichiro, Kasahara Satoshi, Keika Kunihiro, Hori Tomoaki, Matsuoka Ayako, Kasahara Yoshiya, Kumamoto Atsushi, Kasaba Yasumasa, Tsuchiya Fuminori, Shoji Masafumi, Shinohara Iku, Stolle Claudia

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   125 巻 ( 10 )   2020年10月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    A stable auroral red (SAR) arc is an aurora with a dominant 630 nm emission at subauroral latitudes. SAR arcs have been considered to occur due to the spatial overlap between the plasmasphere and the ring-current ions. In the overlap region, plasmaspheric electrons are heated by ring-current ions or plasma waves, and their energy is then transferred down to the ionosphere where it causes oxygen red emission. However, there have been no study conducted so far that quantitatively examined plasma and electromagnetic fields in the magnetosphere associated with SAR arc. In this paper, we report the first quantitative evaluation of conjugate measurements of a SAR arc observed at 2204 UT on 28 March 2017 and investigate its source region using an all-sky imager at Nyrölä (magnetic latitude: 59.4°N), Finland, and the Arase satellite. The Arase observation shows that the SAR arc appeared in the overlap region between a plasmaspheric plume and the ring-current ions and that electromagnetic ion cyclotron waves and kinetic Alfven waves were not observed above the SAR arc. The SAR arc was located at the ionospheric trough minimum identified from a total electron content map obtained by the GNSS receiver network. The Swarm satellite flying in the ionosphere also passed the SAR arc at ~2320 UT and observed a decrease in electron density and an increase in electron temperature during the SAR-arc crossing. These observations suggest that the heating of plasmaspheric electrons via Coulomb collision with ring-current ions is the most plausible mechanism for the SAR-arc generation.

    DOI: 10.1029/2020JA028068

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  22. Temporal and Spatial Variations of Total Electron Content Enhancements During a Geomagnetic Storm on 27 and 28 September 2017 査読有り

    Shinbori Atsuki, Otsuka Yuichi, Sori Takuya, Tsugawa Takuya, Nishioka Michi

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   125 巻 ( 7 )   2020年7月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    Temporal and spatial evolutions of total electron content (TEC) and electron density in the ionosphere during a geomagnetic storm that occurred on 27 and 28 September 2017 have been investigated using global TEC data obtained from many Global Navigation Satellite System stations together with the ionosonde, geomagnetic field, Jicamarca incoherent scatter and Super Dual Auroral Radar Network (SuperDARN) radar data. Our analysis results show that a clear enhancement of the ratio of the TEC difference (rTEC) first occurs from noon to afternoon at high latitudes within 1 hr after a sudden increase and expansion of the high-latitude convection and prompt penetration of the electric field to the equator associated with the southward excursion of the interplanetary magnetic field. Approximately 1–2 hr after the onset of the hmF2 increase in the midlatitude and low-latitude regions associated with the high-latitude convection enhancement, the rTEC and foF2 values begin to increase and the enhanced rTEC region expands to low latitudes within 1–2 hr. This signature suggests that the ionospheric plasmas in the F2 region move at a higher altitude due to local electric field drift, where the recombination rate is smaller, and that the electron density increases due to additional production at the lower altitude in the sunlit region. Later, another rTEC enhancement related to the equatorial ionization anomaly appears in the equatorial region approximately 1 hr after the prompt penetration of the electric field to the equator and expands to higher latitudes within 3–4 hr.

    DOI: 10.1029/2019JA026873

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  23. Characteristics of GNSS Total Electron Content Enhancements Over the Midlatitudes During a Geomagnetic Storm on 7 and 8 November 2004 査読有り

    Sori T., Shinbori A., Otsuka Y., Tsugawa T., Nishioka M.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   124 巻 ( 12 ) 頁: 10376 - 10394   2019年12月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    The characteristics of global electron density variations in the ionosphere during a geomagnetic storm on 7 and 8 November 2004 were investigated using total electron content (TEC) obtained from the global navigation satellite system (GNSS). The regions of enhanced TEC over North America, Europe, and Japan first appeared in the middle-latitude regions. The TEC enhancements over North America showed a rapid longitudinal expansion and reached a wide longitudinal extent during the initial and main phases of the geomagnetic storm. TEC enhancements were simultaneously observed in both North America and Japan at 05:00 UT on 8 November. Observation data from the Defense Meteorological Satellite Program showed a slight enhancement of electron density at 850 km below the equatorward boundary of the middle-latitude trough (45–48°N in geomagnetic latitude) over the Pacific Ocean. This electron density variation may correspond to the TEC enhancements observed in both Japan and North America. These results imply that an enhanced TEC region existed between North America and Japan. The TEC enhancement in Japan appeared with a magnetic conjugacy in the Southern Hemisphere, indicating one of the characteristics of storm-enhanced density (SED). Moreover, TEC enhancements simultaneously appeared from Japan to central Asia at 11:00 UT on 8 November, corresponding to the early recovery phase of the geomagnetic storm. From the above results, it is suggested that SED phenomena can be simultaneously generated over a wide longitudinal width (~100°). The longitudinal extent of this SED event is 2.5–5.0 times longer than those reported by previous studies.

    DOI: 10.1029/2019JA026713

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  24. Observation and characterization of traveling ionospheric disturbances induced by solar eclipse of 20 March 2015 using incoherent scatter radars and GPS networks 査読有り

    Panasenko Sergii V, Otsuka Yuichi, van de Kamp Max, Chernogor Leonid F., Shinbori Atsuki, Tsugawa Takuya, Nishioka Michi

    JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS   191 巻   2019年9月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Atmospheric and Solar-Terrestrial Physics  

    We present the results of a comprehensive study of traveling ionospheric disturbances (TIDs) occurring over Europe during the total solar eclipse of 20 March 2015. For detection of wave structures and estimation of TID parameters, two remote sensing techniques were combined: incoherent scatter (IS) radars and European and Finnish dense GPS receiver networks. Similar procedures were applied for processing both IS and GPS data. We developed a new method enabling to analyze TEC data separately in the temporal and spatial domain. For the first time, we produced maps of band-pass filtered TEC variations and reported both large- and medium-scale prevailing TIDs observed during this solar eclipse, both having similar periods of about 50 – 60 min. The downward phase progression indicates that TIDs were induced by atmospheric gravity waves generated at lower altitudes. The variations in IS power attained peak relative amplitudes of 0.22 (22%) at 220 km over Tromsø and of 0.17 (17%) at 200 km over Kharkiv. The vertical phase velocity was about 57 m/s over Tromsø. It increased from 25 to 170 m/s over Kharkiv with altitude increasing from 120 to 310 km. Over Western Europe, large-scale TIDs (LSTIDs) had prevailing north-east direction over the region from 45°to 50°N and 2°W to 8°E. Here, their average horizontal phase velocity Vm was 803±281m∕s and the absolute amplitudes of TEC variations usually do not exceed 0.17 TECU. For this region, we found strong differences in LSTID propagation azimuth between the solar eclipse day and the two adjacent days of 19 and 21 March 2015, used as reference. This most likely indicates that these LSTIDs were directly caused by the solar eclipse through local heating/cooling processes occurring during the passing of the Moon penumbra. Over another region, limited by 44°–50°N and 13°–19°E, the LSTIDs had south-east propagation. Over Finland, the LSTIDs also propagated southeastward having Vm=774±202m∕s and TEC amplitudes up to 0.6 TECU. A possible evidence of LSTID generation at high latitudes indirectly by this solar eclipse through an excitation of slow magnetosonic waves was experimentally detected. Medium-scale TIDs (MSTIDs) propagated southeastward over both regions having Vm values of 144±54m∕s over Western Europe and of 104±43m∕s over Finland. Over Northern Europe, the maximum MSTID amplitudes were greater by a factor of 5 compared to those over Western Europe and reached 0.4 TECU. We did not detect a clear difference in MSTID propagation between solar eclipse and reference days. The IS and GPS results are in consistency with each other. The detected TID parameters of predominant periods, relative amplitudes, altitude range and MSTID horizontal propagation direction generally correspond to the results of other studies.

    DOI: 10.1016/j.jastp.2019.05.015

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  25. Direct Observations of Traveling Ionospheric Disturbances as Focusers of Solar Radiation: Spectral Caustics 査読有り

    Koval Artem, Chen Yao, Tsugawa Akuya, Otsuka Yuichi, Shinbori Atsuki, Nishioka Michi, Brazhenko Anatoliy, Stanislavsky Aleksander, Konovalenko Aleksander, Zhang Qing-He, Monstein Christian, Gorgutsa Roman

    ASTROPHYSICAL JOURNAL   877 巻 ( 2 )   2019年6月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Astrophysical Journal  

    The solar radiation focusing effect is related to the specific phenomenon of propagation of the Sun-emitted HF and VHF waves through terrestrial ionosphere. This natural effect is observed with ground-based radio instruments running within the 10-200 MHz range as distinctive patterns - the spectral caustics (SCs) - on the solar dynamic spectra. It has been suggested that SCs are associated with medium-scale traveling ionospheric disturbances (MSTIDs). In this paper, we present the first direct observations of SCs induced by MSTIDs, using solar dynamic spectra with SCs obtained by different European radio telescopes on 2014 January 8 and simultaneous two-dimensional detrended total electron content (dTEC) maps over Europe. Spatial examination of dTEC maps as well as precise timing analysis of the maps and the dynamic spectra have been performed. First, we found several pairs of one-to-one (TID-SC) correspondences. The study provides strong observational evidence supporting the suggestion that MSTIDs are the cause of SCs.

    DOI: 10.3847/1538-4357/ab1b52

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  26. Response of the Ionosphere-Plasmasphere Coupling to the September 2017 Storm:What Erodes the Plasmasphere so Severley? 査読有り

    Obana Yuki, Maruyama Naomi, Shinbori Atsuki, Hashimoto Kumiko K., Fedrizzi Mariangel, Nose Masahito, Otsuka Yuichi, Nishitani Nozomu, Hori Tomoaki, Kumamoto Atsushi, Tsuchiya Fuminori, Matsuda Shoya, Matsuoka Ayako, Kasahara Yoshiya, Yoshikawa Akimasa, Miyoshi Yoshizumi, Shinohara Iku

    SPACE WEATHER-THE INTERNATIONAL JOURNAL OF RESEARCH AND APPLICATIONS   17 巻 ( 6 ) 頁: 861 - 876   2019年6月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Space Weather  

    We report an extreme erosion of the plasmasphere arising from the September 2017 storm. The cold electron density is identified from the upper limit frequency of upper hybrid resonance waves observed by the Plasma Wave Experiment instrument onboard the Exploration of energization and Radiation in Geospace/Arase satellite. The electron density profiles reveal that the plasmasphere was severely eroded during the recovery phase of the storm and the plasmapause was located at L = 1.6–1.7 at 23 UT 8 September 2017. This is the first report of deep erosion of the plasmasphere (LPP < 2) with the in situ observation of the electron density. The degree of the severity is much more than what is expected from the relatively moderate value of the SYM-H minimum (−146 nT). We attempt to find a possible explanation for the observed severe depletion by using both observational evidence and numerical simulations. Our results suggest that the middle latitude electric field had penetrated from the high-latitude storm time convection for several hours. Such an unusually long-lasting penetration event can cause this observed degree of severity.

    DOI: 10.1029/2019SW002168

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  27. Relationship between the low-latitude coronal hole area, solar wind velocity, and geomagnetic activity during solar cycles 23 and 24 査読有り

    Nakagawa Yumi, Nozawa Satoshi, Shinbori Atsuki

    EARTH PLANETS AND SPACE   71 巻 ( 1 )   2019年2月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Earth, Planets and Space  

    In order to statistically investigate the relationship between the low-latitude coronal holes (CHs), the solar wind speed, and the geomagnetic activity in solar cycles 23 (1996–2008) and 24 (2009–2016), we conducted a superposed epoch analysis of the variations in CH area, solar winds, the interplanetary magnetic field (IMF), and geomagnetic indices (AL, AU, and SYM-H) for the period from 1996 to 2016. We further divided the temporal variations of the IMF into four types and then investigated the variations in solar winds, the IMF, and the geomagnetic indices before and after the corotating interaction region (CIR) reached Earth’s magnetosphere in each case. As a result, we observed a north–south asymmetry in the CH area, which shows that the CH area was much larger in the southern hemisphere than in the northern hemisphere during solar cycles 23 and 24. In addition, the CH area for solar cycle 24 tended to appear in a wider latitude region compared with that for solar cycle 23. The maximum values of the CH area and the solar wind speed in solar cycle 24 tended to be smaller than those in solar cycle 23. The relationship between these maximum values showed a positive correlation for both solar cycles. The distribution was larger for solar cycle 23 than for solar cycle 24. The variations in solar wind speed and the geomagnetic indices (AE and SYM-H) associated with CIRs in solar cycle 24 tended to be smaller than those in solar cycle 23. We conclude that the geomagnetic activity for solar cycle 24 associated with CIRs was slightly lower compared with that for solar cycle 23. This decrease in geomagnetic activity was due to a decrease in the dawn-to-dusk solar wind electric field intensity, which is obtained as the product of the solar wind speed and the north–south component of the solar wind magnetic field.[Figure not available: see fulltext.].

    DOI: 10.1186/s40623-019-1005-y

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  28. The Space Physics Environment Data Analysis System (SPEDAS) 査読有り

    Angelopoulos V., Cruce P., Drozdov A., Grimes E. W., Hatzigeorgiu N., King D. A., Larson D., Lewis J. W., McTiernan J. M., Roberts D. A., Russell C. L., Hori T., Kasahara Y., Kumamoto A., Matsuoka A., Miyashita Y., Miyoshi Y., Shinohara I., Teramoto M., Faden J. B., Halford A. J., McCarthy M., Millan R. M., Sample J. G., Smith D. M., Woodger L. A., Masson A., Narock A. A., Asamura K., Chang T. F., Chiang C. -Y., Kazama Y., Keika K., Matsuda S., Segawa T., Seki K., Shoji M., Tam S. W. Y., Umemura N., Wang B. -J., Wang S. -Y., Redmon R., Rodriguez J. V., Singer H. J., Vandegriff J., Abe S., Nose M., Shinbori A., Tanaka Y. -M., UeNo S., Andersson L., Dunn P., Fowler C., Halekas J. S., Hara T., Harada Y., Lee C. O., Lillis R., Mitchell D. L., Argall M. R., Bromund K., Burch J. L., Cohen I. J., Galloy M., Giles B., Jaynes A. N., Le Contel O., Oka M., Phan T. D., Walsh B. M., Westlake J., Wilder F. D., Bale S. D., Livi R., Pulupa M., Whittlesey P., DeWolfe A., Harter B., Lucas E., Auster U., Bonnell J. W., Cully C. M., Donovan E., Ergun R. E., Frey H. U., Jackel B., Keiling A., Korth H., McFadden J. P., Nishimura Y., Plaschke F., Robert P., Turner D. L., Weygand J. M., Candey R. M., Johnson R. C., Kovalick T., Liu M. H., McGuire R. E., Breneman A., Kersten K., Schroeder P.

    SPACE SCIENCE REVIEWS   215 巻 ( 1 )   2019年2月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Space Science Reviews  

    With the advent of the Heliophysics/Geospace System Observatory (H/GSO), a complement of multi-spacecraft missions and ground-based observatories to study the space environment, data retrieval, analysis, and visualization of space physics data can be daunting. The Space Physics Environment Data Analysis System (SPEDAS), a grass-roots software development platform (www.spedas.org), is now officially supported by NASA Heliophysics as part of its data environment infrastructure. It serves more than a dozen space missions and ground observatories and can integrate the full complement of past and upcoming space physics missions with minimal resources, following clear, simple, and well-proven guidelines. Free, modular and configurable to the needs of individual missions, it works in both command-line (ideal for experienced users) and Graphical User Interface (GUI) mode (reducing the learning curve for first-time users). Both options have “crib-sheets,” user-command sequences in ASCII format that can facilitate record-and-repeat actions, especially for complex operations and plotting. Crib-sheets enhance scientific interactions, as users can move rapidly and accurately from exchanges of technical information on data processing to efficient discussions regarding data interpretation and science. SPEDAS can readily query and ingest all International Solar Terrestrial Physics (ISTP)-compatible products from the Space Physics Data Facility (SPDF), enabling access to a vast collection of historic and current mission data. The planned incorporation of Heliophysics Application Programmer’s Interface (HAPI) standards will facilitate data ingestion from distributed datasets that adhere to these standards. Although SPEDAS is currently Interactive Data Language (IDL)-based (and interfaces to Java-based tools such as Autoplot), efforts are under-way to expand it further to work with python (first as an interface tool and potentially even receiving an under-the-hood replacement). We review the SPEDAS development history, goals, and current implementation. We explain its “modes of use” with examples geared for users and outline its technical implementation and requirements with software developers in mind. We also describe SPEDAS personnel and software management, interfaces with other organizations, resources and support structure available to the community, and future development plans.

    DOI: 10.1007/s11214-018-0576-4

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  29. Temporal and Spatial Variations of Mid-Latitude Ionospheric Trough during a Geomagnetic Storm Based on Global GNSS-TEC and Arase Satellite Observations 査読有り

    Shinbori A., Otsuka Y., Tsugawa T., Nishioka M., Kumamoto A., Tsuchia F., Matsuda S., Kasahara Y.

    2018 2nd URSI Atlantic Radio Science Meeting, AT-RASC 2018     2018年9月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:2018 2nd URSI Atlantic Radio Science Meeting, AT-RASC 2018  

    The Earth's plasmasphere is the vast 'doughnut' shaped dense plasma region of the magnetosphere that is filled with cold ions and electrons of ionospheric origin. The plasmaspheric plasma density shows an abrupt drop by a factor of 5 or more around 4-6 Re (Re: Earth's radius). The boundary has been called 'plasmapause'. Since the plasmaspheric cold plasma controls generation of plasma waves, their propagation features, and particle acceleration via wave-particle interaction, detailed investigation of the temporal and spatial variations of the plasmasphere and plasmapause location during a geomagnetic storm is important for understanding a change in plasma wave environments in the inner magnetosphere. Recent studies showed a good correlation between the mid-latitude ionospheric trough and the plasmapause for both geomagnetically quiet and disturbed conditions [1]. However, they did not reach the detailed investigation of the characteristics of spatial variation of the mid-latitude ionospheric trough and its temporal variation with high resolution due to limitation of a usage of global GIM of TEC. In this study, we investigate characteristics of temporal and spatial variations of the mid-latitude ionospheric trough during a geomagnetic storm which occurred on April 4, 2017 using the 5-min average Global Navigation Satellite System (GNSS) Total Electron Content (TEC) data together with solar wind, interplanetary magnetic field, geomagnetic field, and Arase High Frequency Analyzer (HFA) (subcomponent of Plasma Wave Experiment (PWE)) observation data. As a result, the location of the mid-latitude ionospheric trough moves equatorward from 60 to 48 degrees within 4 hours after the onset of the storm main phase. The movement speed increases from 1.3 to 3.5 degrees of geomagnetic latitude per hour after the onset of storm-time substorm. The increasing speed means an abrupt shrink of the plasmasphere due to a sudden enhancement of convection electric field in the inner magnetosphere associated with the substorm onset. The location of the mid-latitude ionospheric trough identified from the minimum value of the GNSS-TEC data from the auroral to mid-latitude regions is almost in good agreement with that of an abrupt drop of electron density derived from the upper limit frequency of the upper hybrid resonance (UHR) waves detected by the HFA instrument onboard the Arase satellite. In this case, the electron density profile along the Arase orbit shows an irregular variation of the electron density near the plasmapause. During the main phase of the geomagnetic storm, the geomagnetic longitude distribution of the mid-latitude trough location shows a wavy structure with its scale of 1000-2500 km. The shape of the wavy structure varies with time during the storm main phase. This phenomenon has not yet been reported before due to the limitation of ground dense GNSS receiver networks. After the start of the recovery phase of the geomagnetic storm, the mid-latitude ionospheric trough quickly moves poleward from 48 to 60 degrees in geomagnetic latitude within 4 hours in a geomagnetic longitude range of 310-360 degrees in geomagnetic longitude. The average speed of the poleward movement is 2.3 degrees of geomagnetic latitude per hour.

    DOI: 10.23919/URSI-AT-RASC.2018.8471490

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  30. Temporal and spatial variations of mid-latitude ionospheric trough during a geomagnetic storm based on global GNSS-TEC and Arase satellite observations

    Shinbori Atsuki, Otsuka Yuichi, Tsugawa Takuya, Nishioka Michi, Kumamoto Atsushi, Tsuchia Fuminori, Matsuda Shoya, Kasahara Yoshiya

    2018 2ND URSI ATLANTIC RADIO SCIENCE MEETING (AT-RASC)     頁: .   2018年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  31. Temporal and Spatial Variations of Storm Time Midlatitude Ionospheric Trough Based on Global GNSS-TEC and Arase Satellite Observations 査読有り

    Shinbori Atsuki, Otsuka Yuichi, Tsugawa Takuya, Nishioka Michi, Kumamoto Atsushi, Tsuchiya Fuminori, Matsuda Shoya, Kasahara Yoshiya, Matsuoka Ayako, Ruohoniemi J. Michael, Shepherd Simon G., Nishitani Nozomu

    GEOPHYSICAL RESEARCH LETTERS   45 巻 ( 15 ) 頁: 7362 - 7370   2018年8月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Geophysical Research Letters  

    Temporal and spatial variations of the midlatitude ionospheric trough during a geomagnetic storm on 4 April 2017 have been investigated using Global Navigation Satellite System total electron content data together with Arase satellite observations. After the geomagnetic storm commencement, the trough minimum location moves equatorward from 60 to 48° in geomagnetic latitude within 4 hr. The trough minimum location identified from the Global Navigation Satellite System total electron content data is located near the footprint of an abrupt drop of electron density detected by the Arase High-Frequency Analyzer instrument. The longitudinal variation of the trough minimum location shows a significant variation with a scale of 1,000–2,500 km during both storm and quiet times. This phenomenon has not yet been reported by previous studies. After the onset of the storm recovery phase, the trough minimum location rapidly moves poleward back to the quiet time location within 4 hr.

    DOI: 10.1029/2018GL078723

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  32. Total Electron Content Observations by Dense Regional and Worldwide International Networks of GNSS

    Tsugawa Takuya, Nishioka Michi, Ishii Mamoru, Hozumi Kornyanat, Saito Susumu, Shinbori Atsuki, Otsuka Yuichi, Saito Akinori, Buhari Suhaila M., Abdullah Mardina, Supnithi Pornchai

    JOURNAL OF DISASTER RESEARCH   13 巻 ( 3 ) 頁: 535-545   2018年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  33. Total electron content observations by dense regional and worldwide international networks of GNSS

    Tsugawa T., Nishioka M., Ishii M., Hozumi K., Saito S., Shinbori A., Otsuka Y., Saito A., Buhari S., Abdullah M., Supnithi P.

    Journal of Disaster Research   13 巻 ( 3 ) 頁: 535 - 545   2018年6月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Disaster Research  

    Two-dimensional ionospheric total electron content (TEC) maps have been derived from ground-based Global Navigation Satellite System (GNSS) receiver networks and applied to studies of various ionospheric disturbances since the mid-1990s. For the purpose of monitoring and researching ionospheric conditions and ionospheric space weather phenomena, we have developed TEC maps of areas over Japan using the dense GNSS network, GNSS Earth Observation NETwork (GEONET), which consists of about 1300 stations and is operated by the Geospatial Information Authority of Japan (GSI). Currently, we are providing high-resolution, two-dimensional maps of absolute TEC, detrended TEC, rate of TEC change index (ROTI), and loss-of-lock on GPS signal over Japan on a real-time basis. Such high-resolution TEC maps using dense GNSS receiver networks are one of the most effective ways to observe, on a scale of several 100 km to 1000 km, ionospheric variations caused by traveling ionospheric disturbances and/or equatorial plasma bubbles, which can degrade single-frequency and differential GNSS positioning/navigation. We have collected all the available GNSS receiver data in the world to expand the TEC observation area. Currently, however, dense GNSS receiver networks are available in only limited areas, such as Japan, North America, and Europe. To expand the two-dimensional TEC observation with high resolution, we have conducted the Dense Regional and Worldwide International GNSS TEC observation (DRAWING-TEC) project, which is engaged in three activities: (1) standardizing GNSS-TEC data, (2) developing a new high-resolution TEC mapping technique, and (3) sharing the standardized TEC data or the information of GNSS receiver network. We have developed a new standardized TEC format, GNSS-TEC EXchange (GTEX), which is included in the Formatted Tables of ITU-R SG 3 Data-banks related to Recommendation ITU-R P.311. Sharing the GTEX TEC data would be easier than sharing the GPS/GNSS data among those in the international ionospheric researcher community. The DRAWING-TEC project would promote studies of medium-scale ionospheric variations and their effect on GNSS.

    DOI: 10.20965/jdr.2018.p0535

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    CiNii Research

  34. Wire Probe Antenna (WPT) and Electric Field Detector (EFD) of Plasma Wave Experiment (PWE) aboard the Arase satellite: specifications and initial evaluation results 査読有り

    Kasaba Yasumasa, Ishisaka Keigo, Kasahara Yoshiya, Imachi Tomohiko, Yagitani Satoshi, Kojima Hirotsugu, Matsuda Shoya, Shoji Masafumi, Kurita Satoshi, Hori Tomoaki, Shinbori Atsuki, Teramoto Mariko, Miyoshi Yoshizumi, Nakagawa Tomoko, Takahashi Naoko, Nishimura Yukitoshi, Matsuoka Ayako, Kumamoto Atsushi, Tsuchiya Fuminori, Nomura Reiko

    EARTH PLANETS AND SPACE   69 巻 ( 1 )   2017年12月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Earth, Planets and Space  

    This paper summarizes the specifications and initial evaluation results of Wire Probe Antenna (WPT) and Electric Field Detector (EFD), the key components for the electric field measurement of the Plasma Wave Experiment (PWE) aboard the Arase (ERG) satellite. WPT consists of two pairs of dipole antennas with ~ 31-m tip-to-tip length. Each antenna element has a spherical probe (60 mm diameter) at each end of the wire (15 m length). They are extended orthogonally in the spin plane of the spacecraft, which is roughly perpendicular to the Sun and enables to measure the electric field in the frequency range of DC to 10 MHz. This system is almost identical to the WPT of Plasma Wave Investigation aboard the BepiColombo Mercury Magnetospheric Orbiter, except for the material of the spherical probe (ERG: Al alloy, MMO: Ti alloy). EFD is a part of the EWO (EFD/WFC/OFA) receiver and measures the 2-ch electric field at a sampling rate of 512 Hz (dynamic range: ± 200 mV/m) and the 4-ch spacecraft potential at a sampling rate of 128 Hz (dynamic range: ± 100 V and ± 3 V/m), with the bias control capability of WPT. The electric field waveform provides (1) fundamental information about the plasma dynamics and accelerations and (2) the characteristics of MHD and ion waves in various magnetospheric statuses with the magnetic field measured by MGF and PWE–MSC. The spacecraft potential provides information on thermal electron plasma variations and structure combined with the electron density obtained from the upper hybrid resonance frequency provided by PWE–HFA. EFD has two data modes. The continuous (medium-mode) data are provided as (1) 2-ch waveforms at 64 Hz (in apoapsis mode, L > 4) or 256 Hz (in periapsis mode, L < 4), (2) 1-ch spectrum within 1–232 Hz with 1-s resolution, and (3) 4-ch spacecraft potential at 8 Hz. The burst (high-mode) data are intermittently obtained as (4) 2-ch waveforms at 512 Hz and (5) 4-ch spacecraft potential at 128 Hz and downloaded with the WFC-E/B datasets after the selection. This paper also shows the initial evaluation results in the initial observation phase.[Figure not available: see fulltext.].

    DOI: 10.1186/s40623-017-0760-x

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  35. Ground-based instruments of the PWING project to investigate dynamics of the inner magnetosphere at subauroral latitudes as a part of the ERG-ground coordinated observation network 査読有り

    Shiokawa Kazuo, Katoh Yasuo, Hamaguchi Yoshiyuki, Yamamoto Yuka, Adachi Takumi, Ozaki Mitsunori, Oyama Shin-Ichiro, Nose Masahito, Nagatsuma Tsutomu, Tanaka Yoshimasa, Otsuka Yuichi, Miyoshi Yoshizumi, Kataoka Ryuho, Takagi Yuki, Takeshita Yuhei, Shinbori Atsuki, Kurita Satoshi, Hori Tomoaki, Nishitani Nozomu, Shinohara Iku, Tsuchiya Fuminori, Obana Yuki, Suzuki Shin, Takahashi Naoko, Seki Kanako, Kadokura Akira, Hosokawa Keisuke, Ogawa Yasunobu, Connors Martin, Ruohoniemi J. Michael, Engebretson Mark, Turunen Esa, Ulich Thomas, Manninen Jyrki, Raita Tero, Kero Antti, Oksanen Arto, Back Marko, Kauristie Kirsti, Mattanen Jyrki, Baishev Dmitry, Kurkin Vladimir, Oinats Alexey, Pashinin Alexander, Vasilyev Roman, Rakhmatulin Ravil, Bristow William, Karjala Marty

    EARTH PLANETS AND SPACE   69 巻 ( 1 )   2017年11月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Earth, Planets and Space  

    The plasmas (electrons and ions) in the inner magnetosphere have wide energy ranges from electron volts to mega-electron volts (MeV). These plasmas rotate around the Earth longitudinally due to the gradient and curvature of the geomagnetic field and by the co-rotation motion with timescales from several tens of hours to less than 10 min. They interact with plasma waves at frequencies of mHz to kHz mainly in the equatorial plane of the magnetosphere, obtain energies up to MeV, and are lost into the ionosphere. In order to provide the global distribution and quantitative evaluation of the dynamical variation of these plasmas and waves in the inner magnetosphere, the PWING project (study of dynamical variation of particles and waves in the inner magnetosphere using ground-based network observations, http://www.isee.Nagoya-u.ac.jp/dimr/PWING/) has been carried out since April 2016. This paper describes the stations and instrumentation of the PWING project. We operate all-sky airglow/aurora imagers, 64-Hz sampling induction magnetometers, 40-kHz sampling loop antennas, and 64-Hz sampling riometers at eight stations at subauroral latitudes (~ 60° geomagnetic latitude) in the northern hemisphere, as well as 100-Hz sampling EMCCD cameras at three stations. These stations are distributed longitudinally in Canada, Iceland, Finland, Russia, and Alaska to obtain the longitudinal distribution of plasmas and waves in the inner magnetosphere. This PWING longitudinal network has been developed as a part of the ERG (Arase)-ground coordinated observation network. The ERG (Arase) satellite was launched on December 20, 2016, and has been in full operation since March 2017. We will combine these ground network observations with the ERG (Arase) satellite and global modeling studies. These comprehensive datasets will contribute to the investigation of dynamical variation of particles and waves in the inner magnetosphere, which is one of the most important research topics in recent space physics, and the outcome of our research will improve safe and secure use of geospace around the Earth.[Figure not available: see fulltext.]

    DOI: 10.1186/s40623-017-0745-9

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  36. Characteristics of Seasonal Variation and Solar Activity Dependence of the Geomagnetic Solar Quiet Daily Variation 査読有り

    Shinbori Atsuki, Koyama Yukinobu, Nose Masahito, Hori Tomoaki, Otsuka Yuichi

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   122 巻 ( 10 ) 頁: 10796 - 10810   2017年10月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    Characteristics of seasonal variation and solar activity dependence of the X and Y components of the geomagnetic solar quiet (Sq) daily variation at Memambetsu in midlatitudes and Guam near the equator have been investigated using long-term geomagnetic field data with 1 h time resolution from 1957 to 2016. The monthly mean Sq variation in the X and Y components (Sq-X and Sq-Y) shows a clear seasonal variation and solar activity dependence. The amplitude of seasonal variation increases significantly during high solar activities and is proportional to the solar F10.7 index. The pattern of the seasonal variation is quite different between Sq-X and Sq-Y. The result of the correlation analysis between the solar F10.7 index and the Sq-X and Sq-Y shows an almost linear relationship, but the slope of the linear fitted line varies as a function of local time and month. This implies that the sensitivity of Sq-X and Sq-Y to the solar activity is different for different local times and seasons. The pattern of the local time and seasonal variations of Sq-Y at Guam shows good agreement with that of a magnetic field produced by interhemispheric field-aligned currents (FACs), which flow from the summer to winter hemispheres in the dawn and dusk sectors and from the winter to summer hemispheres in the prenoon to afternoon sectors. The direction of the interhemispheric FAC in the dusk sector is opposite to the concept of Fukushima's model.

    DOI: 10.1002/2017JA024342

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  37. Propagation and evolution of electric fields associated with solar wind pressure pulses based on spacecraft and ground-based observations 査読有り

    Takahashi N., Kasaba Y., Nishimura Y., Shinbori A., Kikuchi T., Hori T., Ebihara Y., Nishitani N.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   122 巻 ( 8 ) 頁: 8446 - 8461   2017年8月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    We investigate spatial and temporal evolution of large-scale electric fields in the magnetosphere and ionosphere associated with sudden commencements (SCs) using multipoint equatorial magnetospheric (THEMIS, RBSP, and GOES) and ionospheric (C/NOFS) satellites with radars (SuperDARN). A distinct SC event on 17 March 2013 shows that the magnetospheric electric field in the equatorial plane propagates from dayside toward nightside as a fast-mode wave. The ionospheric electric field responds ~41 s after the onset of dayside magnetospheric electric field, which can be explained by the propagation of the Alfvén wave along magnetic field lines. The wavelet analysis shows that the Alfvén wave is dominant in the plasmasphere. Poynting fluxes toward the ionosphere support these propagations. From a statistical analysis of response time, tailward propagation speed is estimated at about 1000–1100 km/s. We also statistically derive a spatial distribution and time evolution of the magnetospheric electric field in the dawn-dusk direction (Ey). Our result shows that negative Ey (dawnward) propagates from noon toward the magnetotail, followed by positive Ey (duskward). The propagation characteristics of electric fields in the equatorial plane depend on magnetic local time. At noon, negative Ey lasts for about 1 min, and positive Ey becomes dominant about 2 min after the SC onset. Negative Ey soon attenuates in the nightside region, while the positive Ey propagates fairly well to the premidnight or postmidnight regions while maintaining a certain amplitude. The enhancement of positive Ey is due to the enhancement of magnetospheric convection associated with the main impulse of SCs.

    DOI: 10.1002/2017JA023990

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  38. Evaluation of momentum flux with radar 査読有り

    Dennis M. Riggin, Toshitaka Tsuda, Atsuki Shinbori

    JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS   142 巻   頁: 98 - 107   2016年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The statistics of gravity wave momentum flux estimation are investigated using data from the MU radar at Shigariki, Japan (136 degrees E, 35 degrees N). The radar has been operating during campaign periods since 1986. The first part of the paper focuses on a multi-day campaign during October 13-31, 1986. The second part of the paper investigates data after 2006 when the radar was operated in a meteor scatter mode. Momentum fluxes are derived from both the turbulent scatter and the meteor scatter measurements, but the techniques are quite different. Probability Distribution Functions are formed using turbulent scatter data. These show that wave packets sometimes have momentum flux magnitudes in excess of 100 m(2) s(-2). The technique for meteor radars, introduced by Hocking (2005), has been widely adopted by the radar community in recent years. The momentum flux estimated using this technique is found to be anti-correlated with the background tidal winds. A validation investigation is carried out for periods with a high meteor echo data rate. The conclusion was that the method can be used to calculate the sign of momentum flux, but does not accurately specify the magnitude. (C) 2016 The Authors. Published by Elsevier Ltd.

    DOI: 10.1016/j.jastp.2016.01.013

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  39. JavaFX-based iUgonet Data Analysis Software (JudasFX)のプロトタイプ開発 査読有り

    小山幸伸, 佐藤由佳, 中野慎也, 八木学, 田中良昌, 阿部修司, 能勢正仁, 蔵川圭, 池田大輔, 梅村宜生, 新堀 淳樹, 上野悟

    宇宙科学情報解析論文誌   ( 第5号 )   2016年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

  40. Response of the incompressible ionosphere to the compression of the magnetosphere during the geomagnetic sudden commencements 査読有り

    Kikuchi T., Hashimoto K. K., Tomizawa I., Ebihara Y., Nishimura Y., Araki T., Shinbori A., Veenadhari B., Tanaka T., Nagatsuma T.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   121 巻 ( 2 ) 頁: 1536 - 1556   2016年2月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    The ionospheric plasma in midlatitude moves upward/downward during the geomagnetic sudden commencement causing the HF Doppler frequency changes; SCF (+ -) and (- +) on the dayside and nightside, respectively, except for the SCF (+ -) in the evening as found by Kikuchi et al. (1985). Although the preliminary and main frequency deviations (PFD, MFD) of the SCF have been attributed to the dusk-to-dawn and dawn-to-dusk potential electric fields, there still remain questions if the positive PFD can be caused by the compressional magnetohydrodynamic (MHD) wave and what causes the evening anomaly of the SCF. With the HF Doppler sounder, we show that the dayside ionosphere moves upward toward the Sun during the main impulse (MI) of the SC, when the compressional wave is supposed to push the ionosphere downward. The motion of the ionosphere is shown to be correlated with the equatorial electrojet, matching the potential electric field transmitted with the ionospheric currents from the polar ionosphere. We confirmed that the electric field of the compressional wave is severely suppressed by the conducting ionosphere and reproduced the SC electric fields using the global MHD simulation in which the potential solver is employed. The model calculations well reproduced the preliminary impulse and MI electric fields and their evening anomaly. It is suggested that the electric potential is transmitted from the polar ionosphere to the equator by the zeroth-order transverse magnetic (TM0) mode waves in the Earth-ionosphere waveguide. The near-instantaneous transmission of the electric potential leads to instantaneous global response of the incompressible ionosphere.

    DOI: 10.1002/2015JA022166

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    Scopus

  41. Measurement of momentum flux using two meteor radars in Indonesia 査読有り

    Naoki Matsumoto, Atsuki Shinbori, Dennis M. Riggin, Toshitaka Tsuda

    ANNALES GEOPHYSICAE   34 巻 ( 3 ) 頁: 369 - 377   2016年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:COPERNICUS GESELLSCHAFT MBH  

    Two nearly identical meteor radars were operated at Koto Tabang (0.20 degrees S, 100.32 degrees E), West Sumatra, and Biak (1.17 degrees S, 136.10 degrees E), West Papua, in Indonesia, separated by approximately 4000 km in longitude on the Equator. The zonal and meridional momentum flux, u'w' and v'w', where u, v, and w are the eastward, northward, and vertical wind velocity components, respectively, were estimated at 86 to 94 km altitudes using the meteor radar data by applying a method proposed by Hocking (2005). The observed u'w' at the two sites agreed reasonably well at 86, 90, and 94 km during the observation periods when the data acquisition rate was sufficiently large enough. Variations in v'w' were consistent between 86, 90, and 94 km altitudes at both sites. The climatological variation in the monthly averaged u'w' and v'w' was investigated using the long-term radar data at Koto Tabang from November 2002 to November 2013. The seasonal variations in u'w' and v'w' showed a repeatable semiannual and annual cycles, respectively. u'w' showed eastward values in February-April and July-September and v'w' was northward in June to August at 90-94 km, both of which were generally anti-phase with the mean zonal and meridional winds, having the same periodicity. Our results suggest the usefulness of the Hocking method.

    DOI: 10.5194/angeo-34-369-2016

    Web of Science

  42. IMF-By dependence of transient ionospheric flow perturbation associated with sudden impulses: SuperDARN observations 査読有り

    Hori Tomoaki, Shinbori Atsuki, Fujita Shigeru, Nishitani Nozomu

    EARTH PLANETS AND SPACE   67 巻 ( 1 )   2015年11月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Earth, Planets and Space  

    A statistical study using a large dataset of Super Dual Auroral Radar Network (SuperDARN) observations is conducted for transient ionospheric plasma flows associated with sudden impulses (SI) recorded on ground magnetic field. The global structure of twin vortex-like ionospheric flows is found to be consistent with the twin vortices of ionospheric Hall current deduced by the past geomagnetic field observations. An interesting feature, which is focused on in this study, is that the flow structures show a dawn-dusk asymmetry depending on the combination of the polarity of SI and interplanetary magnetic field (IMF)-By. Detailed statistics of the SuperDARN observations reveal that the dawn-dusk asymmetry of flow vortices due to IMF-By appears during negative SIs, while such asymmetric characteristics are not seen during positive SIs. On the basis of the upstream observations, we suggest that this particular dawn-dusk asymmetry is caused by the interaction between the pre-existing round convection cell and a pair of the transient convection vortices associated with SIs.

    DOI: 10.1186/s40623-015-0360-6

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    Scopus

  43. Response of ionospheric electric fields at mid-low latitudes during sudden commencements 査読有り

    Takahashi N., Kasaba Y., Shinbori A., Nishimura Y., Kikuchi T., Ebihara Y., Nagatsuma T.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   120 巻 ( 6 ) 頁: 4849 - 4862   2015年6月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    Using in situ observations from the Republic of China Satellite-1 spacecraft, we investigated the time response and local time dependence of the ionospheric electric field at mid-low latitudes associated with geomagnetic sudden commencements (SCs) that occurred from 1999 to 2004. We found that the ionospheric electric field variation associated with SCs instantaneously responds to the preliminary impulse (PI) signature on the ground regardless of spacecraft local time. Our statistical analysis also supports the global instant transmission of electric field from the polar region. In contrast, the peak time detected in the ionospheric electric field is earlier than that of the equatorial geomagnetic field (~20s before in the PI phase). Based on the ground-ionosphere waveguide model, this time lag can be attributed to the latitudinal difference of ionospheric conductivity. However, the local time distribution of the initial excursion of ionospheric electric field shows that dusk-to-dawn ionospheric electric fields develop during the PI phase. Moreover, the westward electric field in the ionosphere, which produces the preliminary reverse impulse of the geomagnetic field on the dayside feature, appears at 18-22h LT where the ionospheric conductivity beyond the duskside terminator (18h LT) is lower than on the dayside. The result of a magnetohydrodynamic simulation for an ideal SC shows that the electric potential distribution is asymmetric with respect to the noon-midnight meridian. This produces the local time distribution of ionospheric electric fields similar to the observed result, which can be explained by the divergence of the Hall current under nonuniform ionospheric conductivity. Key Points Ionospheric electric fields respond instantaneously and globally Instant transmission of electric field is explained by the waveguide model Nonuniform ionospheric conductivity affects LT dependence of electric field

    DOI: 10.1002/2015JA021309

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  44. The capacity-building and science-enabling activities of the IUGONET for the solar-terrestrial research community 査読有り

    Yatagai Akiyo, Sato Yuka, Shinbori Atsuki, Abe Shuji, UeNo Satoru

    EARTH PLANETS AND SPACE   67 巻 ( 1 )   2015年1月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Earth, Planets and Space  

    Background: This paper presents an overview of the capacity-building activities and science-enabling services of the Inter-university Upper atmosphere Global Observation NETwork (IUGONET) project. This Japanese program, which started in 2009, is building a metadata database (MDDB) of ground-based observations and is developing an analysis software to handle the data linked to the MDDB system for use by the solar-terrestrial physics community. Because the institutional members of the IUGONET are mainly universities in Japan, we explore tools that can contribute to advanced education as well as promote research activities. Findings: In this paper, we describe the utilities of the IUGONET for education, including our capacity-building activities in developing countries. We have regularly facilitated training seminars for Japanese students on the use of our tools (IUGONET MDDB and the software), and we have held capacity-building seminars for young scientists in developing countries. In addition to the MDDB, we have prepared various 'gateway' tools for users who are unfamiliar with 'keywords' to search for data. One of these is a geographical display tool that uses Google Earth (KML file), which is included as supplemental material to this paper. The usefulness of the IUGONET has been proven over its first 5 years of operation by the increasing number of its users, which has led to the production of approximately 500 scientific papers, including 42 thesis papers. Conclusions: The IUGONET community collaborates with the Scientific Committee on Solar-Terrestrial Physics program, not only in its scientific activities, but also in the establishment of E-infrastructure and capacity building.

    DOI: 10.1186/s40623-014-0170-2

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    Scopus

  45. Thermal and low-energy ion outflows in and through the polar cap: The polar wind and the low-energy component of the cleft ion fountain 査読有り

    AGU Geophysical Monograph     2015年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  46. Long-term variation in the upper atmosphere as seen in the geomagnetic solar quiet daily variation 査読有り

    Shinbori Atsuki, Koyama Yukinobu, Nose Masahito, Hori Tomoaki, Otsuka Yuichi, Yatagai Akiyo

    EARTH PLANETS AND SPACE   66 巻 ( 1 ) 頁: 1 - 20   2014年12月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Earth, Planets and Space  

    Characteristics of long-term variation in the amplitude of solar quiet (Sq) geomagnetic field daily variation have been investigated using 1-h geomagnetic field data obtained from 69 geomagnetic observation stations within the period of 1947 to 2013. The Sq amplitude observed at these geomagnetic stations showed a clear dependence on the 10- to 12-year solar activity cycle and tended to be enhanced during each solar maximum phase. The Sq amplitude was the smallest around the minimum of solar cycle 23/24 in 2008 to 2009. The relationship between the solar F10.7 index and Sq amplitude was approximately linear but about 53% of geomagnetic stations showed a weak nonlinear relation to the solar F10.7 index. In order to remove the effect of solar activity seen in the long-term variation of the Sq amplitude, we calculated a linear or second-order fitting curve between the solar F10.7 index and Sq amplitude during 1947 to 2013 and examined the residual Sq amplitude, which is defined as the deviation from the fitting curve. As a result, the majority of trends in the residual Sq amplitude that passed through a trend test showed negative values over a wide region. This tendency was relatively strong in Europe, India, the eastern part of Canada, and New Zealand. The relationship between the magnetic field intensity at 100-km altitude and residual Sq amplitude showed an anti-correlation for about 71% of the geomagnetic stations. Furthermore, the residual Sq amplitude at the equatorial station (Addis Ababa) was anti-correlated with the absolute value of the magnetic field inclination. This implies movement of the equatorial electrojet due to the secular variation of the ambient magnetic field.

    DOI: 10.1186/s40623-014-0155-1

    Web of Science

    Scopus

  47. An Interactive Data Language software package to calculate ionospheric conductivity by using numerical models 査読有り

    Koyamaa Yukinobu, Shinbori Atsuki, Tanaka Yoshimasa, Hori Tomoaki, Nose Masahito, Oimatsu Satoshi

    COMPUTER PHYSICS COMMUNICATIONS   185 巻 ( 12 ) 頁: 3398 - 3405   2014年12月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Computer Physics Communications  

    The Inter-university Upper atmosphere Global Observation NETwork (IUGONET) project focuses on handling ground-based observational data of the upper atmosphere. To this end, the project members have been developing a data analysis software package which is based on Interactive Data Language (IDL). Filling the spatial gaps in observational data requires the use of numerical models. In this paper,wediscuss an IDL software package for global ionospheric conductivity by integration of 3rd party numerical models. The model can be used to create further derived models.

    DOI: 10.1016/j.cpc.2014.08.011

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  48. Long-term variation in the upper atmosphere as seen in the geomagnetic solar quiet daily variation 査読有り

    Shinbori, A, Y. Koyama, M, Nose, T. Hori, Y. Otsuka, A. Yatagai

    Earth, Planets and Space   65 巻 ( 155 )   2014年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  49. The capacity-building and science-enabling activities of the IUGONET to the solar-terrestrial research community 査読有り

    Yatagai, A, Y. Sato, A. Shinbori, S. Abe, S. UeNo, IUGONET Team

    Earth, Planets and Space     2014年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  50. Interuniversity Upper Atmosphere Global Observation NETwork (IUGONET) meta-database and analysis software 査読有り

    Yatagai A., Tanaka Y., Abe S., Shinbori A., Yagi M., UeNo S., Koyama Y., Umemura N., Nosé M., Hori T., Sato Y., Hashiguchi N.O., Kaneda N.

    Data Science Journal   13 巻 ( 0 ) 頁: PDA37 - PDA43   2014年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Data Science Journal  

    An overview of the Interuniversity Upper atmosphere Global Observation NETwork (IUGONET) project is presented. This Japanese program is building a meta-database for ground-based observations of the upper atmosphere, in which metadata connected with various atmospheric radars and photometers, including those located in both polar regions, are archived. By querying the metadata database, researchers are able to access data file/information held by data facilities. Moreover, by utilizing our analysis software, users can download, visualize, and analyze upper-atmospheric data archived in or linked with the system. As a future development, we are looking to make our database interoperable with others.

    DOI: 10.2481/dsj.IFPDA-07

    Scopus

    CiNii Research

  51. Progress of the IUGONET system - metadata database for upper atmosphere ground-based observation data 査読有り

    Abe Shuji, Umemura Norio, Koyama Yukinobu, Tanaka Yoshimasa, Yagi Manabu, Yatagai Akiyo, Shinbori Atsuki, UeNo Satoru, Sato Yuka, Kaneda Naoki

    EARTH PLANETS AND SPACE   66 巻 ( 133 )   2014年10月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Earth, Planets and Space  

    Background: The Interuniversity Upper atmosphere Global Observation NETwork (IUGONET) project is a 6-year research project which started in 2009. The objective of this project is to establish a metadata database of various ground-based observation data covering a wide region from the Sun to the Earth; this will encourage more studies on the mechanisms of long-term variations in the upper atmosphere. Findings: For archiving purposes, the metadata database system for cross-searching various data distributed across many universities and institute was developed based on the existing repository software called DSpace as the core component and the Space Physics Archive Search and Extract (SPASE) data model as the metadata format. The IUGONET metadata database is still in operation since it was released in March 2012. The system is continuously examined, tested, and updated to improve its quality. The OpenSearch interface in the IUGONET metadata database allows the user to use external applications easily for exchanging metadata and/or for analyzing data. Conclusions: We conducted self-examination of our product, which was added for planning future directions of the IUGONET project.

    DOI: 10.1186/1880-5981-66-133

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  52. 超高層物理学分野のメタデータ・データベースへの連想検索の適用(宇宙科学情報解析論文誌 第三号) 査読有り

    小山 幸伸, 阿部 修司, 八木 学, 梅村 宜生, 堀 智昭, 新堀 淳樹, 佐藤 由佳, 家森 俊彦, 田中 良昌, 橋口 典子, 上野 悟, 谷田貝 亜紀代

    宇宙航空研究開発機構研究開発報告   13 巻   頁: 89 - 97   2014年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:宇宙航空研究開発機構  

    超高層大気に於ける地球規模の物理現象の機構を解明する為には,様々なデータを用いた分野横断的な研究推進が重要である.インターネット上の様々なデータを直ちに取得する為の基盤が,分野横断的な研究の1つの鍵となる.IUGONETプロジェクトは,複数の研究機関によって分散管理されている,様々なデータの URL等の所在情報等を提供可能なメタデータ・データベースを構築することによって,この課題に対処した.しかしながら,このメタデータ・データベースは広範な研究領域を対象としている為,専門分野外のユーザーにとって単語検索時における適切な検索語句の選択が容易でないことが指摘された.これを補助するべく,検索語句の関連語の取得とそれらを用いた再検索クエリ文字列の自動生成を行う為に,そのメタデータ・データベースと連想検索エンジン GETAssocを連携させた.そして,この連想検索用の辞書を作成する為に, SAO/NASA Astrophysics Data Systemからメタデータを抽出した.再クエリ文字列を生成する為に用意した辞書を用いることで,期待通りの連想検索結果を得ることが出来た.

    CiNii Research

  53. Analysis software for upper atmospheric data developed by the IUGONET project and its application to polar science 査読有り

    Tanaka, Y.-M, A. Shinbori, T. Hori, Y. Koyama, S. Abe, N. Umemura, Y. Sato, M. Yagi, S. UeNo, A. Yatagai, Y. Ogawa, Y. Miyoshi

    Advances in Polar Science, 24, 231-240, doi:10.3724/SP.J.1085.2013.00231     2013年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  54. Global distributions of storm-time ionospheric currents as seen in geomagnetic field variations 査読有り

    Shinbori, A, T. Hori, Y. Tanaka, Y. Koyama, T. Kikuchi, T. Nagatsuma

    Advances in Polar Science, 24, 296-314, doi:10.3724/SP.J.1085.2013.00296   24 巻   頁: 296 - 314   2013年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  55. Inter-university upper atmosphere global observation network (IUGONET) 査読有り

    Hayashi H., Koyama Y., Hori T., Tanaka Y., Abe S., Shinbori A., Kagitani M., Kouno T., Yoshida D., UeNo S., Kaneda N., Yoneda M., Umemura N., Tadokoro H., Motoba T.

    Data Science Journal   12 巻   2013年4月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Data Science Journal  

    An overview of the Inter-university Upper atmosphere Global Observation NETwork (IUGONET) project is presented with a brief description of the products to be developed. This is a Japanese inter-university research program to build the metadata database for ground-based observations of the upper atmosphere. The project also develops the software to analyze the observational data provided by various universities/institutes. These products will be of great help to researchers in efficiently finding, obtaining, and utilizing various data dispersed across the universities/institutes. This is expected to contribute significantly to the promotion of interdisciplinary research, leading to more a comprehensive understanding of the upper atmosphere.

    DOI: 10.2481/dsj.WDS-030

    Scopus

  56. Inter-university upper atmosphere global observation network (IUGONET) 査読有り

    H. Hayashi, Y. Koyama, T. Hori, Y. Tanaka, S. Abe, A. Shinbori, M. Kagitani, T. Kouno, D. Yoshida, S. UeNo, N. Kaneda, M. Yoneda, N. Umemura, H. Tadokoro, T. Motoba

    Data Science Journal   12 巻   頁: WDS179 - WDS184   2013年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Ubiquity Press Ltd  

    An overview of the Inter-university Upper atmosphere Global Observation NETwork (IUGONET) project is presented with a brief description of the products to be developed. This is a Japanese inter-university research program to build the metadata database for ground-based observations of the upper atmosphere. The project also develops the software to analyze the observational data provided by various universities/institutes. These products will be of great help to researchers in efficiently finding, obtaining, and utilizing various data dispersed across the universities/institutes. This is expected to contribute significantly to the promotion of interdisciplinary research, leading to more a comprehensive understanding of the upper atmosphere.

    DOI: 10.2481/dsj.WDS-030

    Scopus

  57. IUGONETメタデータ登録・管理システムの処理性能評価 査読有り

    堀智昭, 梅村宜生, 阿部修司, 小山幸伸, 田中良昌, 林寛生, 林寛生, 上野悟, 新堀淳樹, 佐藤由佳, 八木学

    宇宙航空研究開発機構研究開発報告 JAXA-RR-   ( 12-006 ) 頁: 71 - 78   2013年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    J-GLOBAL

  58. IUGONETメタデータ登録・管理システムの処理性能評価(宇宙科学情報解析論文誌 第二号) 査読有り

    堀 智昭, 梅村 宜生, 阿部 修司, 小山 幸伸, 田中 良昌, 林 寛生, 上野 悟, 新堀 淳樹, 佐藤 由佳, 八木 学

    宇宙航空研究開発機構研究開発報告   12 巻   頁: 71 - 78   2013年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:宇宙航空研究開発機構  

    本論文では,大学間連携プロジェクト「超高層大気長期変動の全球地上ネットワーク観測・研究」IUGONET)において、作成されたメタデータの受付やメタデータ・データベースへの登録を行っている「メタデータ登録・管理システム」のメタデータ登録処理に関する性能試験の結果について報告する.メタデータ登録・管理システムは,フリーのバージョン管理ソフトウェアであるGit を利用したメタデータ受付部と,そこからメタデータ・データベースへメタデータを登録するメタデータインポート部の,2つの処理部で構成される.この2つの処理部の性能を評価するために,実際に作成・登録されたメタデータを用いて,物理マシンおよび仮想マシン上に構築した Linux環境のそれぞれについて,メタデータの処理速度を計測した.その結果,Gitによるメタデータ受付部は物理マシンか仮想マシンかに依らず,メタデータ総数が500万件レベルまで増えても数分以内で処理が完了するのに対して,メタデータインポート部は処理時間が数時間から数十時間とかなり長くなり,特に検索エンジンであるLuceneのインデックス更新については,物理マシンにおける実行速度が仮想マシンのそれより約 4倍高速であることがわかった.メタデータインポート部を物理マシン上に実装した場合,メタデータ総数 500万件では,新規登録メタデータ数10万件につき5時間弱プラスLuceneインデックス更新で21時間ほど処理時間がかかると見積もられる.

    CiNii Research

  59. IUGONET解析ソフトウェアの現状と今後の発展 査読有り

    田中 良昌, 新堀 淳樹, 梅村 宜生, 堀 智昭, 阿部 修司, 小山 幸伸, 林 寛生, 上野 悟, 佐藤 由佳, 谷田貝 亜紀代, 小川 泰信, 三好 由純, 関 華奈子, 宮下 幸長, 瀬川 朋紀

    宇宙航空研究開発機構研究開発報告   12 巻   頁: 63 - 70   2013年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:宇宙航空研究開発機構  

    大学間連携プロジェクト「超高層大気長期変動の全球地上ネットワーク観測・研究」(IUGONET)では,IUGONET参加機関である東北大学,名古屋大学,京都大学,九州大学および国立極地研究所の5 機関が所有する多種多様な超高層大気データを可視化・解析できるデータ解析ソフトウェアUDAS(iUgonet Data Analysis Software)を開発している.UDAS は,IDL 言語で書かれたTHEMIS ミッションのデータ解析ソフトウェアTDAS(THEMIS Data Analysis Software suite)のプラグインソフトであり,TDAS が持つ様々な時系列データの可視化・解析ツールやGUI 機能を利用することができる.我々は,2011 年5 月よりIUGONET ウェブベージにおいてUDAS のβ バージョンの公開を開始し,2012 年2月に本公開を開始した.2012 年10 月以降には,UDAS をTDAS に組み込み,THEMIS ソフトウェアウェブサイトから公開することを計画している.UDAS を提供するにあたり,プログラムの動作確認作業を軽減するためのテストツールの開発も行った.さらに,IDL ライセンスを持たない研究者のために,IDL Virtual Machine 環境で走るTDAS の実行ファイルを開発し,テスト公開を開始した.これらの新しい展開により,UDAS 及びIUGONET 所属機関が所有する地上観測データの利用が促進されることが期待される.

  60. IUGONET解析ソフトウェアの現状と今後の発展 査読有り

    田中 良昌, 新堀 淳樹, 梅村 宜生, 堀 智昭, 阿部 修司, 小山 幸伸, 林 寛生, 上野 悟, 佐藤 由佳, 谷田貝 亜紀代, 小川 泰信, 三好 由純, 関 華奈子, 宮下 幸長, 瀬川 朋紀

    宇宙航空研究開発機構研究開発報告   12 巻 ( 12-006 ) 頁: 63 - 70   2013年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:宇宙航空研究開発機構  

    大学間連携プロジェクト「超高層大気長期変動の全球地上ネットワーク観測・研究」(IUGONET)では,IUGONET参加機関である東北大学,名古屋大学,京都大学,九州大学および国立極地研究所の5 機関が所有する多種多様な超高層大気データを可視化・解析できるデータ解析ソフトウェアUDAS(iUgonet Data Analysis Software)を開発している.UDAS は,IDL 言語で書かれたTHEMIS ミッションのデータ解析ソフトウェアTDAS(THEMIS Data Analysis Software suite)のプラグインソフトであり,TDAS が持つ様々な時系列データの可視化・解析ツールやGUI 機能を利用することができる.我々は,2011 年5 月よりIUGONET ウェブベージにおいてUDAS のβ バージョンの公開を開始し,2012 年2月に本公開を開始した.2012 年10 月以降には,UDAS をTDAS に組み込み,THEMIS ソフトウェアウェブサイトから公開することを計画している.UDAS を提供するにあたり,プログラムの動作確認作業を軽減するためのテストツールの開発も行った.さらに,IDL ライセンスを持たない研究者のために,IDL Virtual Machine 環境で走るTDAS の実行ファイルを開発し,テスト公開を開始した.これらの新しい展開により,UDAS 及びIUGONET 所属機関が所有する地上観測データの利用が促進されることが期待される.

    CiNii Books

    J-GLOBAL

  61. Inter-University upper Atmosphere Global Observation Network (IUGONET) 査読有り

    Hayashi H., UeNo S., Kaneda N., Yoneda M., Umemura N., Tadokoro H., Motoba T., team IUGONET project, Koyama Y., Hori T., Tanaka Y., Abe S., Shinbori A., Kagitani M., Kouno T., Yoshida D.

    Data Science Journal   12 巻 ( 0 ) 頁: WDS179 - WDS184   2013年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:CODATA  

    An overview of the Inter-university Upper atmosphere Global Observation NETwork (IUGONET) project is presented with a brief description of the products to be developed. This is a Japanese inter-university research program to build the metadata database for ground-based observations of the upper atmosphere. The project also develops the software to analyze the observational data provided by various universities/institutes. These products will be of great help to researchers in efficiently finding, obtaining, and utilizing various data dispersed across the universities/institutes. This is expected to contribute significantly to the promotion of interdisciplinary research, leading to more a comprehensive understanding of the upper atmosphere.

    DOI: 10.2481/dsj.WDS-030

  62. Evolution of negative SI-induced ionospheric flows observed by SuperDARN King Salmon HF radar 査読有り

    Hori T., Shinbori A., Nishitani N., Kikuchi T., Fujita S., Nagatsuma T., Troshichev O., Yumoto K., Moiseyev A., Seki K.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   117 巻 ( 12 )   2012年12月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    The spatial evolution of vortex-like flow structures induced by a negative sudden impulse (SI-) is studied on the basis of SuperDARN King Salmon HF radar (KSR) with other ground and satellite data. A large dip in the solar wind density induced a fairly large SI-with a SYM-H amplitude of ∼40 nT. The SI-induced ionospheric flow signatures in the evening sector (MLT ∼ 19 h) were observed by KSR as a westward flow associated with the preliminary impulse (PI) followed by a more intense eastward flow with the main impulse (MI) in the sub-auroral region of the magnetic latitude ∼60-70 deg, consistent with the local ground magnetic field observations. Following the first PI-MI flow sequence, KSR saw a second and possibly third sequence of flow variation which were much smaller in flow amplitude than the first pair but showed qualitatively very similar flow variations and latitudinal/longitudinal propagation characteristics. These observations can be interpreted as aftershocks of the first PI-MI; the same sequence of vortices and field-aligned currents were generated and then drifted anti-sunward with the same mechanism, namely the pumping motion of the dayside magnetosphere. These results are qualitatively consistent with predictions suggested by recent numerical simulations. © 2012. American Geophysical Union. All Rights Reserved.

    DOI: 10.1029/2012JA018093

    Web of Science

    Scopus

  63. Storm-time electron density enhancement in the cleft ion fountain 査読有り

    Kitamura N., Nishimura Y., Chandler M. O., Moore T. E., Terada N., Ono T., Shinbori A., Kumamoto A.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   117 巻 ( 11 )   2012年11月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    To determine the characteristics and origin of observed storm-time electron density enhancements in the polar cap, and to investigate the spatial extent (noon-midnight direction) of associated O<sup>+</sup> ion outflows, we analyzed nearly simultaneous observations of such electron density enhancements from the Akebono satellite and ion upflows from the Polar satellite during a geomagnetic storm occurring on 6 April 2000. The Akebono satellite observed substantial electron density enhancements by a factor of ∼10-90 with a long duration of ∼15 h at ∼2 R<inf>E</inf> in the southern polar region. The Polar satellite outflow measurements in the northern polar cap at ∼7-4 R<inf>E</inf> exhibited velocity filtering of the ∼100 eV to ∼0 eV (from the spacecraft potential) ion outflow from the cleft ion fountain, with resultant temperatures declining from ∼3 eV to 0.03 eV with increasing distance from the cusp. Similar velocity filtering was detected in the southern polar cap at ∼1.8-3.5 R<inf>E</inf>. The region of O<sup>+</sup> ion outflows with fluxes exceeding 5×10<sup>8</sup>/cm<sup>2</sup>/s (mapped to 1000 km altitude) extended ∼10 MLAT (∼1000 km) at the ionosphere from the cusp/cleft into the dayside polar cap at ∼2.5 R<inf>E</inf>. These coordinated Akebono-Polar observations are consistent with the development of storm-time electron density enhancements in the polar cap as a result of the bulk outflow of low-energy plasma as part of the cleft ion fountain. The large spatial scale, large ion fluxes, and the long duration indicate significant supply of very-low-energy O<sup>+</sup> ions to the magnetosphere through this region. © 2012. American Geophysical Union. All Rights Reserved.

    DOI: 10.1029/2012JA017900

    Web of Science

    Scopus

  64. Effect of R2-FAC development on the ionospheric electric field pattern deduced by a global ionospheric potential solver 査読有り

    Nakamizo Aoi, Hiraki Yasutaka, Ebihara Yusuke, Kikuchi Takashi, Seki Kanako, Hori Tomoaki, Ieda Akimasa, Miyoshi Yoshizumi, Tsuji Yuji, Nishimura Yukitoshi, Shinbori Atsuki

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   117 巻 ( 9 )   2012年9月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    Toward the understanding of the effect of the magnetosphere originated disturbances on the global ionospheric electric field and current system, we developed a two-dimensional ionospheric potential solver based on the so-called "thin shell model." The important extension from the previous studies is that our model covers the pole-to-pole ionosphere without placing any boundary at the equator. By using this solver, we investigate how the ionospheric electric field changes from undershielding condition to overshielding condition as the field aligned current (FAC) distribution changes. Calculations are performed by changing IR2/IR1 (the ratio of current intensities of region 2 (R2) and region 1 (R1) FACs) and by moving R2-FAC relative to the fixed R1-FAC. The results are summarized as follows: (1) The turning point, at which the ionosphere turns from undershielding to overshielding is IR2/IR1 = 0.7 ∼ 0.8. (2) With increasing the local time deference between the R1 and R2-FAC peaks, the efficiency of the shielding by R2-FAC increases but the associated potential skews to the nightside. (3) At the same time the shielding effect is weakened around noon, where the R1-potential intrudes to the low latitude region instead, but the R2-potential remains dominant at other local times. The result suggests that the overshielding or undershielding should be identified by observations not only in a limited local time sector but also in the overall ionosphere as much as possible. In order to accurately describe the ionospheric condition, we suggest new classification terms, "complete-overshielding" and "incomplete-overshielding. " © 2012. American Geophysical Union. All Rights Reserved.

    DOI: 10.1029/2012JA017669

    Web of Science

    Scopus

  65. Magnetic local time and latitude dependence of amplitude of the main impulse (MI) of geomagnetic sudden commencements and its seasonal variation 査読有り

    Shinbori Atsuki, Tsuji Yuji, Kikuchi Takashi, Araki Tohru, Ikeda Akihiro, Uozumi Teiji, Baishev Dmitry, Shevtsov Boris M., Nagatsuma Tsutomu, Yumoto Kiyohumi

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   117 巻 ( 8 )   2012年8月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    The magnetic local time and latitude dependence of amplitude of the main impulse (MI) of geomagnetic sudden commencements (SCs) and its seasonal variation have been investigated using high time resolution (1-3 sec) geomagnetic data in the latitudinal range 27-70 degrees for the period 1996-2010. The daytime distribution of the SC-MI amplitude in the sub-auroral and middle latitudes (35-60 degrees) is similar to the DP-2 type geomagnetic variation which shows negative and positive changes in the morning and afternoon, respectively. The magnetic field variation is reversed around the magnetic latitude of 63-65 degrees. This suggests that a pair of field-aligned currents (FACs), resembling the region-1 (R-1) FACs, is located near the magnetic latitude of 63-65 degrees. The nighttime SC amplitude is enhanced significantly in the low and middle latitudes (27-60 degrees). The enhancement is due to the magnetic effect produced by the SC-MI FACs. In the nighttime auroral latitude (63-65 degrees), the SC amplitude decreases steeply due to the enhanced westward auroral electrojet associated with the compression of the magnetosphere. The size of the diurnal variation tends to increase significantly during the summer, compared with that during the winter. This seasonal variation suggests that the DP-2 type ionospheric currents (ICs) and FACs generated during the SC-MI phase are intensified by increased ionospheric conductivities during the summer. It can be concluded that the large-scale MI current system in the ionosphere and magnetosphere is voltage generator. © 2012. American Geophysical Union. All Rights Reserved.

    DOI: 10.1029/2012JA018006

    Web of Science

    Scopus

  66. Magnetic latitude and local time distributions of ionospheric currents during a geomagnetic storm 査読有り

    Tsuji Yuji, Shinbori Atsuki, Kikuchi Takashi, Nagatsuma Tsutomu

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   117 巻 ( 7 )   2012年7月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    In order to clarify the global distribution of ionospheric currents during a geomagnetic storm, we analyzed ground magnetic disturbances from high latitudes to the magnetic equator for the storm on September 7-8, 2002, with the minimum SYM-H value of -168 nT. In this analysis, we investigated magnetic field deviations in the northward component from the SYM-H, as functions of the dipole magnetic latitude (DMLAT) and the magnetic local time (MLT). During the main phase of the storm, the deviations at the low latitudes (10 35 in DMLAT) were positive/negative in the dawn/dusk (0-9/11-24 h MLT) sector. On the other hand, the deviations at the dayside middle latitudes (35-55 in DMLAT) were negative/positive in the morning/afternoon (6-12/13-15 h MLT) sector. The local time distribution at the low latitudes may represent the dawn-dusk asymmetry of the storm time ring current, while that at the dayside middle latitudes coincides with the DP2 currents due to the convection electric field associated with the Region 1 field-aligned currents (R1 FACs). All over the nightside middle latitude, the deviations were positive. This implies the direct effect of the R1 FACs through the Biot-Savart's law. At the geomagnetic equator, the eastward and westward electrojets were intensified on the day and nightside, respectively, being caused by the penetrated dawn-to-dusk convection electric field. We found that the MLT distribution of the magnetic deviations during the recovery phase was in opposite sense to that during the main phase at the dayside middle latitudes. The reversed magnetic disturbances must be due to the overshielding electric field associated with the Region 2 field-aligned currents (R2 FACs). Similarly, the deviations at the dayside and nightside equator were reversed, indicating penetration of the dusk-to-dawn overshielding electric field into the equatorial ionosphere. Based on the above results, we propose a current system including the ionospheric currents at middle latitudes caused by the R1/R2 FACs, equatorial EEJ/CEJ, and asymmetric ring current, during the main/recovery phase of the geomagnetic storm. © 2012. American Geophysical Union.

    DOI: 10.1029/2012JA017566

    Web of Science

    Scopus

  67. IUGONET解析ソフトウェアの開発 査読有り

    田中良昌, 新堀淳樹, 鍵谷将人, 堀智昭, 阿部修司, 小山幸伸, 林寛生, 吉田大紀, 河野貴久, 上野悟, 金田直樹, 米田瑞生, 田所裕康, 元場哲郎, 三好由純, 関華奈子, 宮下幸長, 瀬川朋紀, 小川泰信

    宇宙航空研究開発機構研究開発報告 JAXA-RR-   ( 11-007 ) 頁: 91 - 98   2012年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    J-GLOBAL

  68. IUGONET共通メタデータフォーマットの策定とメタデータ登録管理システムの開発 査読有り

    堀智昭, 鍵谷将人, 田中良昌, 林寛生, 上野悟, 吉田大紀, 阿部修司, 小山幸伸, 河野貴久, 金田直樹, 新堀淳樹, 田所裕康, 米田瑞生

    宇宙航空研究開発機構研究開発報告 JAXA-RR-   ( 11-007 ) 頁: 105 - 111   2012年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    J-GLOBAL

  69. 超高層物理学分野の為のメタデータ・データベースの開発 査読有り

    小山幸伸, 河野貴久, 堀智昭, 阿部修, 吉田大紀, 林寛生, 田中良昌, 新堀淳樹, 上野悟, 金田直樹, 米田瑞生, 元場哲郎, 鍵谷将人, 田所裕康

    宇宙航空研究開発機構研究開発報告 JAXA-RR-   ( 11-007 ) 頁: 99 - 104   2012年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    J-GLOBAL

  70. 大学間連携プロジェクト「超高層大気長期変動の全球地上ネットワーク観測・研究」 査読有り

    林寛生, 小山幸伸, 堀智昭, 田中良昌, 新堀淳樹, 鍵谷将人, 阿部修司, 河野貴久, 吉田大紀, 上野悟, 金田直樹, 米田瑞生, 田所裕康, 元場哲郎

    宇宙航空研究開発機構研究開発報告 JAXA-RR-   ( 11-007 ) 頁: 113 - 120   2012年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    J-GLOBAL

  71. 超高層物理学分野の為のメタデータ・データベースの開発 査読有り

    小山 幸伸, 河野 貴久, 堀 智昭, 阿部 修司, 吉田 大紀, 林 寛生, 田中 良昌, 新堀 淳樹, 上野 悟, 金田 直樹, 米田 瑞生, 元場 哲郎, 鍵谷 将人, 田所 裕康

    宇宙航空研究開発機構研究開発報告   11 巻   頁: 99 - 104   2012年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:宇宙航空研究開発機構  

    著者一同は,平成21 年度から6 年計画で行っている「超高層大気長期変動の全球地上ネットワーク観測・研究(略称IUGONET)」プロジェクトの開発者として,超高層大気長期変動に関する地上観測データのメタデータ・データベースを開発中である.観測データの所在情報に代表される様々なメタデータをデータベース化することにより,複数の機関によって分散管理されている多様な観測データに対するアクセシビリティの向上をもたらす事がIUGONET プロジェクトの目的のひとつである.我々は,SPASE コンソーシアムによって策定されたSPASE データ・モデル/メタデータ・フォーマットをベースに,さらに拡張を施したIUGONET 共通メタデータ・フォーマットを策定した.そして,フリーのリポジトリ・ソフトウェアであり,デフォルトではDublin Core メタデータ・フォーマットのみを取り扱うDSpace に対し,IUGONET 共通メタデータ・フォーマットを取り扱えるようにカスタマイズを施した.本論文では,サイエンスの為のメタデータ・データベースの適用事例のひとつとして,IUGONET メタデータ・データベースについて述べる.

  72. IUGONET共通メタデータフォーマットの策定とメタデータ登録管理システムの開発(宇宙科学情報解析論文誌 第一号) 査読有り

    堀 智昭, 鍵谷 将人, 田中 良昌, 林 寛生, 上野 悟, 吉田 大紀, 阿部 修司, 小山 幸伸, 河野 貴久, 金田 直樹, 新堀 淳樹, 田所 裕康, 米田 瑞生

    宇宙航空研究開発機構研究開発報告   11 巻   頁: 105 - 111   2012年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:宇宙航空研究開発機構  

    本論文では,大学間連携プロジェクト「超高層大気長期変動の全球地上ネットワーク観測・研究」(IUGONET) で策定・公開されたメタデータフォーマットと,そのフォーマットに沿って策定されたメタデータの登録・管理を行うシステムの概要について報告する.IUGONETでは,米国やヨーロッパの研究者で構成されるコンソーシアムが策定したSpace Physics Archive Search and Extract (SPASE) データモデル/メタデータフォーマットをベースにして,超高層大気分野の様々な地上観測データに対応できるように拡張を施すことにより,IUGONET共通メタデータフォーマットを策定した.またIUGONET研究機関で作成されるメタデータを登録・管理するために,フリーのバージョン管理ソフトウェアであるGIT を用いた,メタデータXMLファイルの登録・履歴管理のシステムを構築した.これらを用いることにより,IUGONETでは,参加機関が生産し続ける観測データについてのメタデータの,作成・収集・アーカイブを行っている.

    CiNii Research

  73. 大学間連携プロジェクト「超高層大気長期変動の全球地上ネットワーク観測・研究」(宇宙科学情報解析論文誌 第一号) 査読有り

    林 寛生, 小山 幸伸, 堀 智昭, 田中 良昌, 新堀 淳樹, 鍵谷 将人, 阿部 修司, 河野 貴久, 吉田 大紀, 上野 悟, 金田 直樹, 米田 瑞生, 田所 裕康, 元場 哲郎

    宇宙航空研究開発機構研究開発報告   11 巻   頁: 113 - 120   2012年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:宇宙航空研究開発機構  

    本論文では,大学間連携プロジェクト「超高層大気長期変動の全球地上ネットワーク観測・研究」(略称:IUGONET)の概要と主要な開発プロダクトについて述べる.IUGONETプロジェクトでは,国立極地研究所,東北大学,名古屋大学,京都大学,および九州大学が連携し,これまでに蓄積された多様な地上観測データに関するメタデータのデータベースを構築する. メタデータ・データベースによって,各機関・組織に分散して存在する観測データの横断的な検索・取得を可能にし,観測データの効率的な流通,さらには分野横断型の総合解析による新しい超高層大気研究を促進する.プロジェクトによる開発では,メタデータのフォーマットとしてSPASE (Space Physics Archive Search and Extract)を採用し,超高層大気の地上観測に即した変更を加えることでIUGONET共通メタデータフォーマットを策定する. メタデータ・データベースについては,DSpaceをベースにIUGONETのメタデータに対応したカスタマイズを施すことでシステムを構築する.一方,データ解析ソフトウェアに関しては,IDL (Interactive Data Language)で書かれたTDAS (THEMIS Data Analysis Software suite)をベースに開発を行う.

    CiNii Research

  74. IUGONET解析ソフトウェアの開発(宇宙科学情報解析論文誌 第一号) 査読有り

    田中 良昌, 新堀 淳樹, 鍵谷 将人, 堀 智昭, 阿部 修司, 小山 幸伸, 林 寛生, 吉田 大紀, 河野 貴久, 上野 悟, 金田 直樹, 米田 瑞生, 田所 裕康, 元場 哲郎, 三好 由純, 関 華奈子, 宮下 幸長, 瀬川 朋紀, 小川 泰信

    宇宙航空研究開発機構研究開発報告   11 巻   頁: 91 - 98   2012年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:宇宙航空研究開発機構  

    本論文では,大学間連携プロジェクト「超高層大気長期変動の全球地上ネットワーク観測・研究」(IUGONET)で開発された解析ソフトウェア(UDAS)の概要について報告する.UDASは,IUGONET参加機関である東北大学,名古屋大学,京都大学,九州大学および国立極地研究所の5機関が所有する超高層大気データの可視化・解析ソフトウェアである.UDASは,IDL (Interactive Data Language) で書かれたTHEMISミッションの統合データ解析ツールTDAS (THEMIS Data Analysis Software suite)のプラグインソフトであり,TDASの機能を利用することで,IUGONET所属機関が所有する種類の異なる複数の時系列データの可視化・解析を容易にする.また,初心者でも利用し易いように,GUI (Graphical User Interface) も提供する.UDASは,2011年5月よりIUGONETウェブベージでβバージョンがリリースされている.さらに,UDAS開発の今後の展望について述べる.

    CiNii Research

  75. Solar zenith angle dependence of plasma density and temperature in the polar cap ionosphere and low-altitude magnetosphere during geomagnetically quiet periods at solar maximum 査読有り

    Kitamura N., Ogawa Y., Nishimura Y., Terada N., Ono T., Shinbori A., Kumamoto A., Truhlik V., Smilauer J.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   116 巻 ( 8 )   2011年8月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    We constructed an empirical model of the electron density profile with solar zenith angle (SZA) dependence in the polar cap during geomagnetically quiet periods using 63 months of Akebono satellite observations at solar maximum. The electron density profile exhibits a transition at ∼2000 km altitude only under dark conditions. The electron density and scale height at low altitudes change drastically, by factors of 25 (at 2300 km altitude) and 2.0, respectively, as the SZA increases from 90 to 120. The SZA dependence of the ion and electron temperatures is also investigated statistically on the basis of data obtained by the Intercosmos satellites and European Incoherent Scatter (EISCAT) Svalbard radar (ESR). A drastic change in the electron temperature occurs near the terminator, similarly to that in the electron density profile obtained by the Akebono satellite. The sum of the ion and electron temperatures obtained by the ESR (∼6500 K at ∼1050 km altitude under sunlit conditions and ∼3000 K at ∼750 km altitude under dark conditions) agrees well with the scale height at low altitudes obtained from the Akebono observations, assuming that the temperature is constant and that O + ions are dominant. Comparisons between the present statistical results (SZA dependence of the electron density and ion and electron temperatures) and modeling studies of the polar wind indicate that the plasma density profile (especially of the O+ ion density) in the polar cap is strongly controlled by solar radiation onto the ionosphere by changing ion and electron temperatures in the ionosphere during geomagnetically quiet periods. Copyright © 2011 by the American Geophysical Union.

    DOI: 10.1029/2011JA016631

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  76. Penetration of Magnetospheric Electric Fields to the Low Latitude Ionosphere During Storm/Substorms 査読有り

    Kikuchi, T, K. K. Hashimoto, A. Shinbori, Y. Tsuji, S. Watari

    Aeronomy of the Earth's Atmosphere and Ionosphere IAGA Special Sopron Book Series 2, DOI: 10.1007/978-94-007-0326-1_34, Edit. M.A. Abdu, D.Pancheva, A. Bhattacharyya, Springer Science+Business Media B.V.   2 巻   頁: 443 - 453   2011年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  77. Penetration of Magnetospheric Electric Fields to the Low Latitude Ionosphere During Storm/Substorms 査読有り

    Kikuchi Takashi, Hashimoto Kumiko K., Shinbori Atsuki, Tsuji Yuji, Watari Shin-Ichi

    AERONOMY OF THE EARTH'S ATMOSPHERE AND IONOSPHERE   2 巻   頁: 443 - 453   2011年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1007/978-94-007-0326-1_34

    Web of Science

  78. Direct measurements of the Poynting flux associated with convection electric fields in the magnetosphere 査読有り

    Nishimura Y., Kikuchi T., Shinbori A., Wygant J., Tsuji Y., Hori T., Ono T., Fujita S., Tanaka T.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   115 巻 ( 12 )   2010年12月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    Observations of Poynting fluxes associated with onset of convection electric fields are essential for understanding of electromagnetic energy transport from the solar wind toward the magnetosphere leading to changes in the convection electric field, which is one of the most fundamental parameters in the magnetosphere-ionosphere coupled system. We present Cluster multispacecraft observations of Poynting fluxes associated with abrupt changes in large-scale electric fields during sudden commencements and southward turning of the interplanetary magnetic field (IMF). The Cluster spacecraft detected Poynting fluxes dominated by the field-aligned upward component during the preliminary impulse of sudden commencements and in the initial period after southward turning of the IMF. The upward Poynting flux indicates existence of Alfvn waves transporting electromagnetic energy from the ionosphere toward the magnetosphere leading to magnetospheric convection changes. The waveguide model and global magnetohydrodynamic (MHD) simulation calculating evolution of the Poynting flux following solar wind pressure enhancements also show upward Poynting fluxes propagating from the ionosphere toward the magnetosphere faster than the propagation of compressional waves. We conclude that the ionosphere acts as a channel to transmit electromagnetic energy supplied as field-aligned currents toward a wide region in the magnetosphere-ionosphere system instantaneously, leading to changes in magnetospheric convection electric fields. Copyright 2010 by the American Geophysical Union.

    DOI: 10.1029/2010JA015491

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  79. Observations of very-low-energy (< 10 eV) ion outflows dominated by O+ ions in the region of enhanced electron density in the polar cap magnetosphere during geomagnetic storms 査読有り

    Kitamura N., Nishimura Y., Ono T., Ebihara Y., Terada N., Shinbori A., Kumamoto A., Abe T., Yamada M., Watanabe S., Matsuoka A., Yau A. W.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   115 巻 ( 11 )   2010年11月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    Velocity distributions of upflowing ions in the polar ionosphere are crucial to understand their destinations. Natural plasma wave observations by the plasma wave and sounder experiments and thermal ion observations by the suprathermal ion mass spectrometer onboard the Akebono satellite at ∼9000 km altitude in the polar magnetosphere during the geomagnetic storms showed that ions in the region of enhanced electron density in the polar cap were dominated by very-low-energy O+ ions (∼85%) with upward velocities of 4-10 km s-1, corresponding to streaming energies of 1.3-8.4 eV. The fluxes of very-low-energy upflowing O+ ions exceeded 1 × 10 9 cm-2 s-1 (mapped to 1000 km altitude) across wide regions. These signatures are consistent with high-density plasma supplied by the cleft ion fountain mechanism. Trajectory calculations of O+ ions based on the Akebono observations as the initial condition showed the transport paths and accelerations of the O+ ions and indicated that the velocities of the very-low-energy upflowing O+ ions through the dayside polar cap are enough to reach the magnetosphere under strong convection. The calculations suggest the importance of the very-low-energy upflowing O + ions with large fluxes in the total O+ ion supply toward the magnetosphere, especially the near-Earth tail region and inner magnetosphere. The initially very-low-energy O+ ions can contribute significantly to the ring current formation during geomagnetic storms since some of the O+ ions were transported into the ring current region with typical energies of ring current ions (several tens of keV) in the trajectory calculations. Copyright 2010 by the American Geophysical Union.

    DOI: 10.1029/2010JA015601

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  80. Anomalous occurrence features of the preliminary impulse of geomagnetic sudden commencement in the South Atlantic Anomaly region 査読有り

    Shinbori Atsuki, Nishimura Yukitoshi, Tsuji Yuji, Kikuchi Takashi, Araki Tohru, Ikeda Akihiro, Uozumi Teiji, Otadoy Roland E. S., Utada Hisashi, Ishitsuka Jose, Trivedi Nalin Baual, Dutra Severino L. G., Schuch Nelson Jorge, Watari Shinichi, Nagatsuma Tsutomu, Yumoto Kiyohumi

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   115 巻 ( 8 )   2010年8月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    Occurrence features of the preliminary impulse (PI) of geomagnetic sudden commencement (SC) both in the Pacific Ocean and South Atlantic Anomaly (SAA) regions were investigated using the long-term magnetic field data obtained from the Circum-pan Pacific Magnetometer Network (CPMN) and NICT Space Weather Monitoring (NSWM) magnetometer networks. The low-latitude preliminary reverse impulse (PRI) at Okinawa (OKI: dip latitude = 37.97°) in the Pacific Ocean region appeared in all the magnetic local time (MLT) sectors with the peak occurrence rate of 40% around noon. On the other hand, the PRI occurrence rate at Santa Maria (SMA: dip latitude = -34.35°) near the center of the SAA region showed a significant enhancement in the daytime sector (0800-1600 h, MLT) with the peak value of 80%, which resembles the occurrence feature of the equatorial PRI. Moreover, the PRI amplitude around noon at SMA was about 3.0 times larger than that at OKI. From the calculation of the ionospheric conductivity derived from the IRI-2007 and NRLMSISE-00 models, it is shown that the height-integrated conductivity was more enhanced in the SAA region (SMA), where the ambient magnetic field intensity is weak, compared with that in the Pacific Ocean region (OKI). Therefore, the anomalous increase of the PRI occurrence and amplitude is caused by the significant enhancement of the ionospheric conductivity due to the weakness of the ambient magnetic field intensity in the SAA region. Copyright © 2010 by the American Geophysical Union.

    DOI: 10.1029/2009JA015035

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  81. Anomalous Enhancement of Occurrence of the Preliminary Impulse of Geomagnetic Sudden Commencement (SC) at Low Latitude in the South Atlantic Anomaly (SAA) region 査読有り

    Shinbori A, Y. Nishimura, Y. Tsuji, T. Kikuchi, T. Araki, A. Ikeda, T. Uozumi, R. Otadoy, H. Utada, J. Ishitsuka, N. Trivedi, S. Dutra, N. Schuch, S. Watari, T. Nagatsuma, K. Yumoto

    Journal of Geophysical Research: Space Physics, Volume 115, Issue A8, CiteID: A08309, doi: 10.1029/2009JA015035   115 巻 ( A8 )   2010年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  82. Temporal variations and spatial extent of the electron density enhancements in the polar magnetosphere during geomagnetic storms 査読有り

    Kitamura N., Nishimura Y., Ono T., Kumamoto A., Shinbori A., Iizima M., Matsuoka A., Hairston M. R.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   115 巻   2010年7月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1029/2009JA014499

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  83. Penetration of magnetospheric electric fields to the equator and their effects on the low-latitude ionosphere during intense geomagnetic storms 査読有り

    Veenadhari B., Alex S., Kikuchi T., Shinbori A., Singh Rajesh, Chandrasekhar E.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   115 巻 ( A3 )   2010年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1029/2009JA014562

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  84. Response of convection electric fields in the magnetosphere to IMF orientation change 査読有り

    Nishimura Y., Kikuchi T., Wygant J., Shinbori A., Ono T., Matsuoka A., Nagatsuma T., Brautigam D.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   114 巻 ( 9 )   2009年9月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    The transient response of convection electric fields in the inner magnetosphere to southward turning of the interplanetary magnetic field (IMF) is investigated using in-situ electric field observations by the CRRES and Akebono spacecraft. Electric fields earthward of the inner edge of the electron plasma sheet show quick responses simultaneously with change in ionospheric electric fields, which indicates the arrival of the first signal related to southward turning. A coordinated observation of the electric field by the CRRES and Akebono spacecraft separated by 5 RE reveals a simultaneous increase in the dawn-dusk electric field in a wide region of the inner magnetosphere. A quick response associated with the southward turning of the IMF is also identified in in-situ magnetic fields. It indicates that the southward turning of the IMF initiates simultaneous (less than 1 min) enhancements of ionospheric electric fields, convection electric fields in the inner magnetosphere, and the ring or tail current and region 2 FACs. In contrast, a quick response of convection electric fields is not identified in the electron plasma sheet. A statistical study using 161 events of IMF orientation change in 1991 confirms a prompt response within 5 min for 80% of events earthward of the electron plasma sheet, while a large time lag of more than 30 min is identified in electric fields in the electron plasma sheet. The remarkable difference in the response of electric fields indicates that electric fields in the electron plasma sheet are weakened by high conductance in the magnetically conjugated auroral ionosphere. Copyright 2009 by the American Geophysical Union.

    DOI: 10.1029/2009JA014277

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  85. Magnetic latitude and local time dependence of the amplitude of geomagnetic sudden commencements 査読有り

    Shinbori Atsuki, Tsuji Yuji, Kikuchi Takashi, Araki Tohru, Watari Shinichi

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   114 巻   2009年4月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1029/2008JA013871

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  86. Magnetic latitude and local time dependence of the amplitude of geomagnetic sudden commencements 査読有り

    Shinbori A., Tsuji Y., Kikuchi T., Araki T., Watari S.

    Journal of Geophysical Research: Space Physics   114 巻 ( 4 )   2009年4月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    Statistical analysis of the main impulse (MI) amplitude of geomagnetic sudden commencements (SCs) in a region from the middle latitudes to equator has been made using the long-term geomagnetic field data obtained from the Yap (geomagnetic latitude, θ = 0.38°), Guam (θ = 5.22°), Okinawa (θ = 16.54°), Kakioka (θ = 27.18°), Memanbetsu (θ = 35.16°), and St. Paratunka (θ = 45.58°) stations. The magnetic local time (MLT) dependence of SC amplitude in the middle latitudes showed magnetic field variations produced by two-cell ionospheric currents (DP 2-type currents) which are driven by the dawn-to-dusk electric field accompanying a pair of field-aligned currents (FACs). The effect of the DP 2-type currents at least expands to the low latitude (θ = 16.54°). In this region, the DL part of SC produced by the enhanced Chapman-Ferraro currents can be dominant, but the DP part of SC contaminated 7% of the DL one. On the other hand, at the daytime equator between 8:00 and 16:00 (MLT), the SC amplitude is considerably enhanced with its peak amplitude of 3.24 (normalized SYM-H value) around 11:00 (MLT) due to the Cowling effect. Another interesting point is that the SC amplitude in the nighttime sector was enhanced at all the stations again, and its peak value increases with increasing magnetic latitude. This result suggests that the effect of the FACs associated with the MI phase of SC expands to the equator. Copyright 2009 by the American Geophysical Union.

    DOI: 10.1029/2008JA013871

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  87. Seasonal variations of the electron density distribution in the polar region during geomagnetically quiet periods near solar maximum 査読有り

    Kitamura N., Shinbori A., Nishimura Y., Ono T., Iizima M., Kumamoto A.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   114 巻 ( 1 )   2009年1月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    Meridional electron density distributions above 45 invariant latitude (ILAT) during geomagnetically quiet periods are statistically studied. Electron density data were obtained from plasma waves observed by the Akebono satellite from March 1989 to February 1991 (near solar maximum) in an altitude range of 274-10,500 km. Field-aligned electron density profiles were fitted by the sum of exponential and power law functions. The transition height, where the power law term equals the exponential term, is highest in the summer (at low solar zenith angle (SZA)) at ∼4000 km and lowest in the winter (at high SZA) at ∼1800 km in a region of ILAT ≥ 70; this is caused by the larger scale height in the summer (∼550 km) than that in the winter (∼250 km). The largest seasonal variation and SZA dependence of the electron density are found at an altitude of ∼2000 km with a factor of ∼50 (∼104 /cc in the summer, ∼103 /cc in the winter) in the trough, auroral, and polar cap regions. The seasonal variation and SZA dependence are smaller, about a factor of 5-10, above ∼5000 km. Day-night asymmetries in each season (within a factor of 5) are smaller than the seasonal variation. The scale height is larger in the dayside than in the nightside in each season. These results indicate that photoionization processes in the ionosphere strongly control electron density distributions up to at least ∼5000 km in the trough, auroral, and polar cap regions. Copyright 2009 by the American Geophysical Union.

    DOI: 10.1029/2008JA013288

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  88. Magnetic latitude and local time dependence of the amplitude of geomagnetic sudden commencements 査読有り

    A. Shinbori, Y. Tsuji, T. Kikuchi, T. Araki, S. Watari

    Journal of Geophysical Research A: Space Physics   114 巻 ( 4 )   2009年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1029/2008JA013871

  89. SC-associated ionospheric electric fields at low latitude: FM-CW radar observation 査読有り

    Ikeda, A, K. Yumoto, M. Shinohara, K. Nozaki, A. Yoshikawa, A. Shinbori

    Mem. Fac. Sci., Kyushu Univ., Ser. D, Earth and Planet. Sci.,XXXII, 1-6   32 巻 ( 1 ) 頁: 1 - 6   2008年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  90. Generation mechanism of Z-mode waves in the equatorial plasmasphere 査読有り

    Nishimura Y., Ono T., Iizima M., SHINBORI A., KUMAMOTO A.

    Earth, planets and space   59 巻 ( 9 ) 頁: 1027 - 1034   2007年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Terra Scientific Pub. Co.  

  91. Evolution of ring current and radiation belt particles under the influence of storm-time electric fields 査読有り

    Nishimura Y., Shinbori A., Ono T., Iizima M., Kumamoto A.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   112 巻 ( A6 )   2007年6月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Geophysical Research: Space Physics  

    Electric field and potential distributions in the inner magnetosphere during geomagnetic storms have been investigated using the Akebono/EFD data. Using this electric field, we study injection of ring current particles and acceleration of radiation belt electrons by single-particle calculations. During the main phase, the dawn-dusk electric field is intensified especially in a range of 2 < L < 5 with a maximum amplitude of 6 mV/m on the duskside, and a two-cell convection pattern with a potential difference of 180 kV is identified. The convection pattern on the equatorial plane is significantly distorted with a large potential drop of 70 kV on the dawn and dusk sectors, indicating an intrinsic source of large-scale electric field in the inner magnetosphere. The plasma sheet ions are gathered into the dusk to premidnight sector in the inner magnetosphere in the region of enhanced electric field due to the strong E × B drift. The ions are transported into around 4 R E with an acceleration of more than 1 order of magnitude within 40 min, conserving the first adiabatic invariants. Relativistic electrons with initial energy of some hundreds of kiloelectron volts at 5 RE are energized to more than 100 keV for 3 hours. The energy spectrum during the recovery phase of 9 October 1990 geomagnetic storm observed by the CRRES satellite is reproduced without the radial diffusion or nonadiabatic acceleration by plasma waves. It is possible that this acceleration process is the inhomogeneity of the large-scale electric field, which corresponds to the ∇ × E term along orbits of electrons around the Earth. Copyright 2007 by the American Geophysical Union.

    DOI: 10.1029/2006JA012177

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  92. Electrostatic electron cyclotron harmonic waves observed by the Akebono satellite near the equatorial region of the plasmasphere 査読有り

    Shinbori A., Ono T., Iizima M., KUMAMOTO A., SHIRAI S., HANAOKA A., OKAMOTO K., OHASHI M., OYA H.

    Earth, planets and space   59 巻 ( 6 ) 頁: 613 - 629   2007年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Terra Scientific Pub. Co.  

  93. Electrostatic electron cyclotron harmonic waves observed by the Akebono satellite near the equatorial region of the plasmasphere 査読有り

    新堀 淳樹

    Earth, Planets and Space (印刷中)     2007年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    CiNii Research

  94. Electrostatic electron cyclotron harmonic waves observed by the Akebono satellite near the equatorial region of the plasmasphere 査読有り

    Shinbori A., Ono T., Iizima M., Kumarnot A., Shirai S., Hanaoka A., Okamoto K., Ohashi M., Oya H.

    EARTH PLANETS AND SPACE   59 巻 ( 6 ) 頁: 613 - 629   2007年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    Web of Science

  95. Electrostatic electron cyclotron harmonic waves observed by the Akebono satellite near the equatorial region of the plasmasphere 査読有り

    Shinbori A., Ono T., Iizima M., Kumamoto A., Shirai S., Hanaoka A., Okamoto K., Ohashi M., Oya H.

    Earth, Planets and Space   59 巻 ( 6 ) 頁: 613 - 629   2007年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Earth, Planets and Space  

    Analysis of the plasma wave observation data provided by the plasma waves and sounder experiment (PWS) on board the Akebono satellite frequently reveals the presence of electrostatic electron cyclotron harmonic (ESCH) waves in the low-latitude region (MLAT < 45°) of the plasmasphere within an altitude range from about 3000 km to the apogee of the satellite (initial apogee was 10,500 km). Even at moderate or low geomagnetic activity, intense ESCH waves often appear near the equatorial region of the plasmasphere above the upper hybrid resonance (UHR) frequency at the lowest harmonic number branch of the fQn ESCH waves. We identified these plasma waves as the equatorial plasmasphere fQn waves (EP-fQn). The spectra of the EP-fQn waves are characterized by a narrow band structure and by a strong nature, with a wave intensity that ranges from 3.46 × 10-8 to 3.31 × 10-4 V/m. The maximum intensity is nearly coincident with the upper limit of the PWS receiver in the low-gain mode. Statistical analysis results reveal that the EP-fQn waves are observable in all the local time sectors; however, the occurrence probability shows a clear enhancement in the early morning sector of 01-03 MLT in the plasmasphere. The EP-fQn wave activities are suppressed within a period of strong magnetic disturbances as well as solar minimum phase. The linear dispersion relation analysis using a two-component plasma model reveals that supra-thermal plasma with the energy of about 750 eV and with a large temperature anisotropy (A = T-perp/T-parallel - 1 > 40) must be present in order to realize an appearance of a positive growth rate at the observed frequency and propagation angle of the ESCH waves. Since the hot plasma with such a high anisotropy has not been detected, the validity of the present two-component plasma model remains an open question. The occurrence feature of the ESCH waves showed that there is a constant activation or a constant flow-in of free energy to generate the strong plasma instability of ESCH waves near the post-midnight sector of the plasmasphere. The existence of ESCH waves revealed that the nature of the plasmaspheric plasma is more turbulent and active than has been believed. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences; TERRAPUB.

    DOI: 10.1186/BF03352723

    Web of Science

    Scopus

  96. Generation mechanism of Z-mode waves in the equatorial plasmasphere 査読有り

    Nishimura Y., Ono T., Iizima M., Shinbori A., Kumamoto A.

    EARTH PLANETS AND SPACE   59 巻 ( 9 ) 頁: 1027 - 1034   2007年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    Web of Science

  97. Generation mechanism of Z-mode waves in the equatorial plasmasphere 査読有り

    Nishimura Y., Ono T., Iizima M., Shinbori A., Kumamoto A.

    Earth, Planets and Space   59 巻 ( 9 ) 頁: 1027 - 1034   2007年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Earth, Planets and Space  

    In order to clarify the generation mechanism of Z-mode waves observed in the equatorial plasmasphere, the growth rate of Z-mode electromagnetic waves has been calculated under the higher-order cyclotron interaction process. Z-mode waves can interact with some tens of keV electrons with large pitch angles even in the dense cold background, and the amplitude is consistent with the Akebono plasma wave measurements. UHR and whistler mode waves are also excited by the same electron distribution, and this is also consistent with observations. The origin of these energetic electrons are identified as the ring current electrons injected into the plasmasphere by the intense large-scale electric field during geomagnetic storms, accelerated perpendicular to the ambient magnetic field and confined around the geomagnetic equator conserving the first and second adiabatic invariants. Since the intensity of Z-mode and UHR waves is associated with the development and decay of the ring current, ring current particles are most possible candidate for the free energy source of these waves. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences; TERRAPUB.

    DOI: 10.1186/BF03352043

    Scopus

  98. Storm-time electric field distribution in the inner magnetosphere 査読有り

    Nishimura Y., Shinbori A., Ono T., Iizima M., Kumamoto A.

    Geophysical Research Letters   33 巻 ( 22 )   2006年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Geophysical Research Letters  

    The distribution of the storm-time electric field in the inner magnetosphere has been investigated by using the Akebono/EFD data within a period from 1989 to 1995. During the main phase of geomagnetic storms, the strong electric field appears between L = 2 and L = 6 in both dawn and dusk sectors with the magnitude from 2 to 4 mV/m, and the maximum value appears at L = 3 in the dusk sector. During the recovery and weakly disturbed period, the region with intense electric field moves outward with decreasing the amplitude. This structure of the localized electric field is quite different from the Volland-Stern electric field model, suggesting the existence of another electric field source other than the large-scale convection electric field. During quiet periods, although the electric field fairly follows the corotation electric field, the distribution at L = 3.5 indicates a small deviation from pure corotation. Copyright 2006 by the American Geophysical Union.

    DOI: 10.1029/2006GL027510

    Web of Science

    Scopus

  99. Enhancements of magnetospheric convection electric field in the inner magnetosphere associated with sudden commencements 査読有り

    Shinbori, A, T. Ono, M. Iizima, A. Kumamoto

    Advances in Space Research, Volume 38, Issue 8, 1595-1607, doi: 10.1016/j.asr.2005.05.082     2006年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.asr.2005.05.082

  100. Enhancements of magnetospheric convection electric field associated with sudden commencements in the inner magnetosphere and plasmasphere regions 査読有り

    新堀 淳樹

    Advances in space Research 38     頁: 1595 - 1607   2006年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    CiNii Research

  101. Enhancements of magnetospheric convection electric field associated with sudden commencements in the inner magnetosphere and plasmasphere regions 査読有り

    A. Shinbori, T. Ono, M. Iizima, A. Kumamoto, Y. Nishimura

    ADVANCES IN SPACE RESEARCH   38 巻 ( 8 ) 頁: 1595 - 1607   2006年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCI LTD  

    Electric field variations in the inner magnetosphere and plasmasphere regions associated with sudden commencements (SCs) are investigated by using the observation data of the Akebono satellite which has been carried out more than 15 years since 1989. 117 of 153 SC events in the low-latitude (MLAT &lt; 45 degrees) region, which occurred within a period from March 1989 to January 1996, showed a shift of the magnetospheric convection electric field with the magnitude of 0.1-3.2 mV/m about 1 min after the electric field signature with a bi-polar waveform due to the passage of fast-mode hydromagnetic (HM) waves. The increase of the convection electric field takes place in the entire magnetic local time sector in the inner magnetosphere. The amplitude does not depend on L-value and magnetic local time but is proportional to the SC amplitude measured at Kakioka. The majority of the electric field enhancements persist for about 4-14 min. The origin of the convection electric field in the inner magnetosphere is a plasma motion caused by the compression of the magnetosphere due to the solar wind shock and discontinuity. (C) 2005 COSPAR. Published by Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.asr.2005.05.082

    Web of Science

  102. Statistical studies of fast and slow Z-mode plasma waves in and beyond the equatorial plasmasphere based on long-term Akebono observations 査読有り

    Yukitoshi Nishimura, T. Ono, M. Iizima, A. Shinbori, A. Kumamoto, H. Oya

    Earth, Planets and Space   58 巻 ( 3 ) 頁: 343 - 346   2006年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Springer Berlin  

    In order to investigate spatial and temporal variations of fast and slow Z-mode waves frequently observed in the equatorial plasmasphere, statistical studies have been performed by using plasma wave observation data obtained by the Akebono satellite within a period from 1989 to 1995. It has been clarified that fast and slow Z-mode waves are intensified within ±5° of geomagnetic latitudes in an altitude range from 6000 km to the apogee (10500 km) of the satellite without obvious local time dependence. Long-term averaged intensity of fast Z-mode waves has almost the same orders of magnitude as that of slow Z-mode waves. These results indicate that significant part of fast Z-mode waves are not produced by the linear mode conversion process from slow Z-mode waves, but excited by more direct process. Furthermore, the region of intensified fast and slow Z-mode waves has been spread in a wider geomagnetic latitude range of ±10° during geomagnetic storms. These evidences suggest that one of the possible free energy sources is ring current particles injected into the equatorial region of the plasmasphere during geomagnetic storms. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS)
    The Seismological Society of Japan
    The Volcanological Society of Japan
    The Geodetic Society of Japan
    The Japanese Society for Planetary Sciences
    TERRAPUB.

    DOI: 10.1186/BF03351930

    Scopus

  103. Electrodynamics in the duskside inner magnetosphere and plasmasphere during a super magnetic storm on March 13-15, 1989 査読有り

    A Shinbori, Y Nishimura, T Ono, M Iizima, A Kumamoto, H Oya

    EARTH PLANETS AND SPACE   57 巻 ( 7 ) 頁: 643 - 659   2005年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:TERRA SCIENTIFIC PUBL CO  

    Variations of cold plasma density distribution and large-scale electric field in the inner magnetosphere and plasmasphere during a geomagnetic storm were investigated by using the observation data of the Akebono satellite which has been carried out for more than 15 yeas since March, 1989. We focus on the super geomagnetic storm on March 13-15, 1989, for which the maximum negative excursion of the Dst index was -589 nT. During the main phase of the magnetic storm, the strong convection electric field with a spatially inhomogeneous structure appears in the inner magnetosphere between L = 2.0 and 7.0. The averaged intensity of the electric field was in a range of about 2.5-9.2 mV/m. The spatial distribution in the magnetic equatorial region indicates that the magnitude within an L-value range of 2.2-7.0 is much larger than that observed at L = 7.0-10.0. Associated with the appearance of the strong convection electric field, the cold plasma density near the trough region around L = 3.0-6.0 was enhanced with one or two order magnitude, compared with that in the magnetically quiet condition. This implies that a mount of the ionospheric plasma may be supplied from the topside ionosphere into the trough and plasmasphere regions by the frictional heating due to the fast plasma convection in the ionosphere as pointed out by previous studies on the enhancements of plasma density in these regions, based on incoherent scatter radar and total electron content (TEC) observations (e.g., Yeh and Foster, 1990; Foster et al., 2004). During the recovery phase of the magnetic storm, the convection electric field observed in the inner magnetosphere and plasmasphere regions recovers within 3-4 days almost up to the level of the magnetically quiet condition.

    DOI: 10.1186/BF03351843

    Web of Science

  104. SC related electric and magnetic field phenomena observed by the Akebono satellite inside the plasmasphere 査読有り

    A Shinbori, T Ono, M Iizima, A Kumamoto

    EARTH PLANETS AND SPACE   56 巻 ( 2 ) 頁: 269 - 282   2004年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:TERRA SCIENTIFIC PUBL CO  

    Electric and magnetic field variations inside the plasmasphere associated with SCs identified on the ground are analyzed based on the Akebono satellite observations which have been carried out more than 13 years since March 1989. 126 electric field observation data corresponding to SCs show abrupt change of intensity as well as direction within a few minutes inside the plasmasphere. Temporal variations of the electric field showed a bipolar waveform with the amplitude range of 0.2-38 mV/m. The electric field signature is followed by a dumping oscillation with the period of Pc3-4 ranges. The magnetic field variations of 33 SCs also show an abrupt increase of 0.2-65 nT within a few minutes, which indicate the compression of the magnetosphere due to the discontinuity of solar wind. The initial excursion of the electric field during SCs tends to be directed westward. The amplitude does not show a dependence on magnetic local time that has been observed outside the plasmasphere. The magnitude of the electric field variations tends to be proportional with the power of 0.6 to the magnetic field variation in the plasmasphere. The Poynting vector of the initial SC impulse is directed toward the earth, which suggests that energy of magnetic disturbances associated with SCs propagates toward the earth inside the plasmasphere with the refraction due to the plasma density gradient. One of the most interesting results from the present study is that a DC offset of the Ey component of the electric field appears after the initial electric field impulse associated with SCs. This signature is interpreted to be a magnetospheric convection electric field penetration into the inner plasmasphere (L=2.5). The intensity of the offset of the Ey field gradually increases by 0.5-2.0 mV/m about 1-2 minutes after the onset of the initial electric field impulse and persists about 10-30 minutes.

    DOI: 10.1186/BF03353409

    Web of Science

  105. Sudden commencements related plasma waves observed by the Akebono satellite in the polar region and inside the plasmasphere region 査読有り

    A Shinbori, T Ono, M Iizima, A Kumamoto, H Oya

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   108 巻 ( A12 )   2003年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER GEOPHYSICAL UNION  

    Plasma wave phenomena associated with sudden commencements (SC) are analyzed using the database of the Akebono satellite observations that have been carried out for more than 13 years since March 1989. All the 719 data sets simultaneously observed in the periods of SC events show that plasma waves are enhanced with one-to-one correspondence to SCs in entire regions of the polar cap, auroral zone, and plasmasphere within a response time of +/-90 s. In the middle latitude and equatorial regions of the plasmasphere, intensification and frequency shift of electromagnetic whistler mode, LHR waves, and ion cyclotron harmonic waves are found. The electric field variations in this region also show clear response to the onset of SCs with the amplitude of 0.2-30 mV/m. The variations are observed in the nightside as well as dayside sectors, and no clear dependence of magnetic latitude, local time, and L shell is found. On the other hand, electrostatic whistler mode waves and electromagnetic ion cyclotron waves which show broadband spectra are generated in the high-latitude region. Spectra of low-energy particles observed simultaneously with the enhancement of these plasma waves show that electron fluxes are enhanced in all of pitch angle bins of the low-energy particle detector onboard the Akebono satellite. Near the cusp region, the ion fluxes are more enhanced in the upward direction than in the downward direction along the magnetic field lines. In about half of the cases of the high-latitude events, sudden appearance and intensification of AKR are also found after the onsets of SC. The delay time between the onsets of SC and AKR enhancement shows several minutes with the average time of 5.7 min. Time differences between the onsets of SC measured at Kakioka Magnetic Observatory and plasma wave enhancements observed by the Akebono satellite show positive correlation with possible delay time according to the propagation route of SC disturbances. Propagation character of SC disturbances shows two group signatures: one group takes a route which crosses the geomagnetic equator region with an average speed of 389.5 km/s. The speed is almost consistent with plasmaspheric fast-mode MHD wave velocity. The other group takes a route which starts from the dayside cusp region. In the second case, the SC disturbances propagate through the polar ionosphere region from the dayside to the nightside sectors with an average speed of 47 km/ s in the X-GSM coordinate corresponding to the ionospheric fast-mode MHD wave velocity.

    DOI: 10.1029/2003JA009964

    Web of Science

  106. SC-related kilometric and hectometric radiations observed by the Akebono satellite in the polar regions 査読有り

    Shinbori, A, T. Ono, M. Izima, K. Kumamoto, H. Oya

    Advances in polar upper atmosphere research   17 巻   頁: 60 - 76   2003年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  107. SC-triggered plasma waves observed by the Akebono satellite in the polar regions and the plasmasphere 査読有り

    Shinbori, A, T. Ono, H. Oya

    Advances in polar upper atmosphere research   16 巻   頁: 126 - 135   2002年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

▼全件表示

MISC 206

  1. Thermal and low-energy ion outflows in and through the polar cap: The polar wind and the low-energy component of the cleft ion fountain 査読有り

    新堀 淳樹  

    AGU Geophysical Monograph   頁: .   2016年10月

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    記述言語:英語  

  2. Relationship between solar wind dynamic pressure and amplitude of geomagnetic sudden commencement (SC) 査読有り

    Araki Tohru, Shinbori Atsuki  

    EARTH PLANETS AND SPACE68 巻   2016年5月

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    記述言語:英語  

    DOI: 10.1186/s40623-016-0444-y

    Web of Science

  3. Measurement of momentum flux using two meteor radars in Indonesia 査読有り

    Matsumoto Naoki, Shinbori Atsuki, Riggin Dennis M., Tsuda Toshitaka  

    ANNALES GEOPHYSICAE34 巻 ( 3 ) 頁: 369-377   2016年5月

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    記述言語:英語  

    DOI: 10.5194/angeo-34-369-2016

    Web of Science

  4. Simultaneous ground- and satellite-based observation of MF/HF auroral radio emissions 査読有り

    Sato Yuka, Kumamoto Atsushi, Katoh Yuto, Shinbori Atsuki, Kadokura Akira, Ogawa Yasunobu  

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS121 巻 ( 5 ) 頁: 4530-4541   2016年5月

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    記述言語:英語  

    DOI: 10.1002/2015JA022101

    Web of Science

  5. JavaFX-based iUgonet Data Analysis Software (JudasFX)のプロトタイプ開発 査読有り

    小山幸伸, 佐藤由佳, 中野慎也, 八木学, 田中良昌, 阿部修司, 能勢正仁, 蔵川圭, 池田大輔, 梅村宜生, 新堀 淳樹, 上野悟  

    宇宙科学情報解析論文誌 ( 第5号 ) 頁: .   2016年3月

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    記述言語:日本語  

  6. Long-term variation of ionospheric electric field estimated from the amplitude of geomagnetic solar quiet daily variation

    Shinbori, A, Y. Koyama, M. Nose, T. Hori, Y. Otsuka  

    2015 ISEE workshop: International GEMSIS and ASINACTR-G2602 Workshop: Future Perspectives of Researches in Space Physics   2016年3月

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    記述言語:英語   掲載種別:講演資料等(セミナー,チュートリアル,講習,講義他)  

  7. 地磁気日変化振幅から推定される電離圏電場の長期変動について

    新堀淳樹, 小山幸伸, 能勢正仁, 堀 智昭, 大塚雄一  

        2016年3月

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    記述言語:日本語   掲載種別:講演資料等(セミナー,チュートリアル,講習,講義他)  

  8. 多様な観測データベースを用いた地球大気環境の長期変動に関する研究

    新堀 淳樹  

    第307回生存圏シンポジウム「生存圏ミッションシンポジウム」   2016年3月

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    記述言語:日本語   掲載種別:講演資料等(セミナー,チュートリアル,講習,講義他)  

  9. Evaluation of momentum flux with radar 査読有り

    Riggin Dennis M., Tsuda Toshitaka, Shinbori Atsuki  

    JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS142 巻   頁: 98-107   2016年2月

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    記述言語:英語  

    DOI: 10.1016/j.jastp.2016.01.013

    Web of Science

  10. Response of the incompressible ionosphere to the compression of the magnetosphere during the geomagnetic sudden commencements 査読有り

    T. Kikuchi, K. K. Hashimoto, I. Tomizawa, Y. Ebihara, Y. Nishimura, T. Araki, A. Shinbori, B. Veenadhari, T. Tanaka, T. Nagatsuma  

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS121 巻 ( 2 ) 頁: 1536-1556   2016年2月

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    記述言語:英語  

    The ionospheric plasma in midlatitude moves upward/downward during the geomagnetic sudden commencement causing the HF Doppler frequency changes; SCF (+-) and (-+) on the dayside and nightside, respectively, except for the SCF (+-) in the evening as found by Kikuchi et al. (1985). Although the preliminary and main frequency deviations (PFD, MFD) of the SCF have been attributed to the dusk-to-dawn and dawn-to-dusk potential electric fields, there still remain questions if the positive PFD can be caused by the compressional magnetohydrodynamic (MHD) wave and what causes the evening anomaly of the SCF. With the HF Doppler sounder, we show that the dayside ionosphere moves upward toward the Sun during the main impulse (MI) of the SC, when the compressional wave is supposed to push the ionosphere downward. The motion of the ionosphere is shown to be correlated with the equatorial electrojet, matching the potential electric field transmitted with the ionospheric currents from the polar ionosphere. We confirmed that the electric field of the compressional wave is severely suppressed by the conducting ionosphere and reproduced the SC electric fields using the global MHD simulation in which the potential solver is employed. The model calculations well reproduced the preliminary impulse and MI electric fields and their evening anomaly. It is suggested that the electric potential is transmitted from the polar ionosphere to the equator by the zeroth-order transverse magnetic (TM0) mode waves in the Earth-ionosphere waveguide. The near-instantaneous transmission of the electric potential leads to instantaneous global response of the incompressible ionosphere.

    DOI: 10.1002/2015JA022166

    Web of Science

  11. IUGONETプロジェクトの活動報告

    新堀淳樹, 八木学, 田中良昌, 梅村宣生, 上野悟, 能勢正仁, 小山幸伸, 阿部修司, IUGONET, プロジェクトチーム  

    太陽研連シンポジウム「ひので10年目の成果とSolar-Cを柱とする太陽研究の新展開」   2016年2月

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    記述言語:日本語   掲載種別:講演資料等(セミナー,チュートリアル,講習,講義他)  

  12. Long-term variation in the ionosphere and lower thermosphere as seen in the geomagnetic solar quiet daily variation 査読有り

    AGU Fall Meeting 2015   2015年12月

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    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)  

  13. 地上‐衛星観測に基づく、磁気嵐時の電離圏・プラズマ圏電場変動について

    新堀 淳樹  

    ワークショップ「プラズマ圏の観測と予測モデルの構築」   2015年12月

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    記述言語:日本語   掲載種別:講演資料等(セミナー,チュートリアル,講習,講義他)  

  14. IMF-By dependence of transient ionospheric flow perturbation associated with sudden impulses: SuperDARN observations 査読有り

    Hori Tomoaki, Shinbori Atsuki, Fujita Shigeru, Nishitani Nozomu  

    EARTH PLANETS AND SPACE67 巻   2015年11月

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    記述言語:英語  

    DOI: 10.1186/s40623-015-0360-6

    Web of Science

  15. 地磁気日変化に見られる電離圏、下部熱圏における長期変動特性

    新堀淳樹, 小山幸伸, 能勢正仁, 堀智昭, 大塚雄一  

    第138回 SGEPSS総会および講演会   2015年11月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  16. 地磁気静穏日変化から推定される電離圏電場の長期変動

    新堀淳樹, 小山幸伸, 田中良昌, 佐藤由佳, 門倉昭  

    第6回極域科学シンポジウム   2015年11月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  17. IUGONETデータ解析ソフトを利用した太陽地球系結合研究

    新堀淳樹, 八木学, 田中良昌, 梅村宣生, 上野悟, 小山幸伸, 阿部修司, IUGONET, プロジェクトチーム  

    オープンサイエンスデータ推進ワークショップ   2015年9月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  18. 太陽地球結合系研究のための IUGONET データ解析システム

    新堀淳樹, 八木学, 田中良昌, 梅村宣生, 上野悟, 小山幸伸, 阿部修司, IUGONET, プロジェクトチーム  

    宇宙地球惑星科学若手会「夏の学校2015」   2015年9月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  19. GUI-データ解析

    新堀 淳樹  

    第2回「太陽地球環境データ解析に基づく超高層大気の空間・時間変動の解明」 第290回生存圏シンポジウム/平成27年度名大STE研研究集会/平成27年度極地研研究集会   2015年8月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  20. Long-Term Variation in the Upper Atmosphere as Seen in the Geomagnetic Solar Quiet Daily Variation 招待有り 査読有り

    Asia Oceania Geoscience Society 2015   2015年8月

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    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)  

  21. 地磁気日変化振幅に見られる超高層大気変動について

    新堀淳樹, 小山幸伸, 能勢正仁, 堀智昭, 大塚雄一, IUGONETプロジェクトチーム  

    第2回「太陽地球環境データ解析に基づく超高層大気の空間・時間変動の解明」 第290回生存圏シンポジウム/平成27年度名大STE研研究集会/平成27年度極地研研究集会   2015年8月

     詳細を見る

    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  22. 地磁気日変動振幅から見積もられる下部熱圏における風速の長期変動について

    新堀淳樹, 小山幸伸, 能勢正仁, 堀智昭, 大塚雄一  

    中間圏・熱圏・電離圏 (MTI) 研究集会   2015年8月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  23. Response of ionospheric electric fields at mid-low latitudes during sudden commencements 査読有り

    N. Takahashi, Y. Kasaba, A. Shinbori, Y. Nishimura, T. Kikuchi, Y. Ebihara, T. Nagatsuma  

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS120 巻 ( 6 ) 頁: 4849-4862   2015年6月

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    記述言語:英語  

    Using in situ observations from the Republic of China Satellite-1 spacecraft, we investigated the time response and local time dependence of the ionospheric electric field at mid-low latitudes associated with geomagnetic sudden commencements (SCs) that occurred from 1999 to 2004. We found that the ionospheric electric field variation associated with SCs instantaneously responds to the preliminary impulse (PI) signature on the ground regardless of spacecraft local time. Our statistical analysis also supports the global instant transmission of electric field from the polar region. In contrast, the peak time detected in the ionospheric electric field is earlier than that of the equatorial geomagnetic field (similar to 20s before in the PI phase). Based on the ground-ionosphere waveguide model, this time lag can be attributed to the latitudinal difference of ionospheric conductivity. However, the local time distribution of the initial excursion of ionospheric electric field shows that dusk-to-dawn ionospheric electric fields develop during the PI phase. Moreover, the westward electric field in the ionosphere, which produces the preliminary reverse impulse of the geomagnetic field on the dayside feature, appears at 18-22h LT where the ionospheric conductivity beyond the duskside terminator (18h LT) is lower than on the dayside. The result of a magnetohydrodynamic simulation for an ideal SC shows that the electric potential distribution is asymmetric with respect to the noon-midnight meridian. This produces the local time distribution of ionospheric electric fields similar to the observed result, which can be explained by the divergence of the Hall current under nonuniform ionospheric conductivity.

    DOI: 10.1002/2015JA021309

    Web of Science

  24. Long-term variation in the upper atmosphere as seen in the geomagnetic solar quiet daily variation 招待有り 査読有り

    26th IUGG General Assembly   2015年6月

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    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)  

  25. Characteristics of long-term variation of the geomagnetic solar quiet daily variation

    Japan Geoscience Union 2015   2015年5月

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    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)  

  26. Long-term variation of upper atmosphere using the IUGONET metadata database and data analysis software (UDAS)

    Japan Geoscience Union 2015   2015年5月

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    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)  

  27. The capacity-building and science-enabling activities of the IUGONET to the solar-terrestrial research community 査読有り

    Yatagai, A, Y. Sato, A. Shinbori, S. Abe, S. UeNo, IUGONET Team  

    Earth, Planets and Space   頁: .   2015年1月

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    記述言語:英語  

  28. Long-term variation in the upper atmosphere as seen in the geomagnetic solar quiet daily variation 査読有り

    Shinbori, A, Y. Koyama, M, Nose, T. Hori, Y. Otsuka, A. Yatagai  

    Earth, Planets and Space65 巻 ( 155 ) 頁: .   2014年12月

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    記述言語:英語  

  29. Characteristics of long-term variation in the amplitude of the geomagnetic solar quiet (Sq) daily variation using the Inter-university Upper atmosphere Global Observation NETwork (IUGONET) data analysis system 査読有り

    AGU Fall Meeting 201412 巻   頁: WDS179-WDS184   2014年12月

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    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)  

    DOI: 10.2481/dsj.WDS-030

  30. 極域-中緯度における地磁気静穏日変化の長期変動特性

    新堀淳樹, 小山幸伸, 田中良昌, 佐藤由佳, 門倉昭  

    第5回極域科学シンポジウム   2014年12月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  31. An overview of the IUGONET project and meta database system

    A meet on ‘Inter-university Upper atmosphere Global Observation NETwork (IUGONET)’   2014年11月

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    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)  

  32. Long-term variation of the upper atmosphere and ionosphere as seen in the geomagnetic solar quiet (Sq) daily variation

    A meet on ‘Inter-university Upper atmosphere Global Observation NETwork (IUGONET)’   2014年11月

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    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)  

  33. 全球地磁気データを用いた磁気嵐時のグローバルな電離圏電流分布

    新堀淳樹, 堀智昭, 田中良昌, 小山幸伸, 菊池崇, 長妻努  

    地球電磁気・地球惑星圏学会第136回総会及び講演会   2014年11月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  34. Temporal and spatial variations of storm-time ionospheric currents as seen in the geomagnetic field

    The 12th International Conference on Substorms (ICS-12)   2014年11月

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    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)  

  35. Mini-training of how to use the IUGONET data analysis software (UDAS)

    A meet on ‘Inter-university Upper atmosphere Global Observation NETwork (IUGONET)’   2014年11月

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    記述言語:英語   掲載種別:講演資料等(セミナー,チュートリアル,講習,講義他)  

  36. 地磁気静穏日変化振幅の長期変動特性

    新堀淳樹, 小山幸伸, 能勢正仁, 堀智昭, 大塚雄一, 谷田貝亜紀代, IUGONETプロジェクトチーム  

    地球電磁気・地球惑星圏学会第136回総会及び講演会   2014年11月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  37. Interuniversity upper atmosphere global observation network (IUGONET) meta-database and analysis software 査読有り

    Yatagai, A, Y. Tanaka, S. Abe, A. Shinbori, M. Yagi, S. UeNo, Y. Koyama, N. Umemura, M. Nosé, T Hori, Y Sato, N. O. Hashiguchi, N Kaneda, IUGONET project team  

    Data Science Journal13 巻   頁: PDA37-PDA43   2014年10月

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    記述言語:英語  

    DOI: 10.2481/dsj.IFPDA-07

  38. Progress of the IUGONET system - metadata database for upper atmosphere ground-based observation data 査読有り

    Abe Shuji, Umemura Norio, Koyama Yukinobu, Tanaka Yoshimasa, Yagi Manabu, Yatagai Akiyo, Shinbori Atsuki, UeNo Satoru, Sato Yuka, Kaneda Naoki  

    EARTH PLANETS AND SPACE66 巻   2014年10月

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    記述言語:英語  

    DOI: 10.1186/1880-5981-66-133

    Web of Science

  39. IUGONET データ解析システムを用いた地磁気静穏日変化振幅の長期変動に関する研究

    新堀淳樹, 小山幸伸, 能勢正仁, 堀智昭, 大塚雄一, 谷田貝亜紀代, IUGONETプロジェクトチーム  

    平成26年度「MTI 研究集会」+「ISS-IMAP 研究集会」合同ワークショップ   2014年9月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  40. IUGONETデータ解析システムを用いた太陽地球結合系の長期変動研究

    新堀淳樹, 八木学, 田中良昌, 谷田貝亜紀代, 梅村宣生, 上野悟, 小山幸伸, 阿部修司, IUGONET, プロジェクトチーム  

    第8回MUレーダー・赤道大気レーダーシンポジウム   2014年9月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  41. An Interactive Data Language software package to calculate ionospheric conductivity by using numerical models 査読有り

    Koyamaa Yukinobu, Shinbori Atsuki, Tanaka Yoshimasa, Hori Tomoaki, Nose Masahito, Oimatsu Satoshi  

    COMPUTER PHYSICS COMMUNICATIONS185 巻 ( 12 ) 頁: 3398-3405   2014年8月

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    記述言語:英語  

    DOI: 10.1016/j.cpc.2014.08.011

    Web of Science

  42. Global Distributions of Storm-time Ionospheric Currents and Electric Fields as Seen in Geomagnetic Field Variations 査読有り

    Asia Oceania Geoscience Society 2014   2014年8月

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    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)  

  43. IUGONETツールがもたらす太陽地球科学研究への貢献

    新堀淳樹, 八木学, 田中良昌, 谷田貝亜紀代, 梅村宣生, 上野悟, 小山幸伸, 阿部修司, IUGONET, プロジェクトチーム  

    平成26年度IUGONET中間報告会   2014年8月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  44. Long-term variation in the upper atmosphere as seen in the geomagnetic solar quiet (Sq) daily variation 査読有り

    Asia Oceania Geoscience Society 2014   2014年8月

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    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)  

  45. TDAS/UDAS GUIによる操作2 (データ解析、軸やラベルの変更方法等)

    新堀 淳樹  

    平成26年度国立極地研究所研究集会 「太陽-地球大気の地上多点観測データ総合解析ワークショップ」   2014年8月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  46. Contribution of the IUGONET data analysis system to a study on coupling processes in the solar-terrestrial system

        2014年4月

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    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)  

  47. Contribution of the IUGONET data analysis system to upper atmospheric researches

        2014年4月

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    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)  

  48. 地磁気日変化に見られる超高層大気の長期変動

    新堀 淳樹, 小山幸伸, 能勢正仁, 堀智昭, 大塚雄一, 谷田貝亜紀代  

    日本地球惑星科学連合大会2014   2014年4月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  49. 磁気嵐時の地磁気変動に見られるグローバルな電離圏電流分布について

    新堀淳樹, 堀智昭, 田中良昌, 小山幸伸, 菊池崇, 長妻努  

    日本地球惑星科学連合大会2014   2014年4月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  50. 磁気嵐時における地磁気変動に見られるグローバルな電離圏電流分布について

    新堀淳樹, 堀智昭, 田中良昌, 小山幸伸, 菊池崇, 長妻努  

    平成25年度名古屋大学太陽地球環境研究所研究集会「太陽地球環境メタデータ・データベースによる時空間変動の学際研究」   2014年3月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  51. 磁気嵐時の地磁気変動に見られる電離圏電流分布について

    新堀淳樹, 堀智昭, 田中良昌, 小山幸伸, 菊池崇, 長妻努  

    電磁圏シンポジウム   2014年3月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  52. Global distributions of storm-time ionospheric currents as seen in geomagnetic field variations 査読有り

    Shinbori, A, T. Hori, Y. Tanaka, Y. Koyama, T. Kikuchi, T. Nagatsuma  

    Advances in Polar Science, 24, 296-314, doi:10.3724/SP.J.1085.2013.0029624 巻   頁: 296-314   2013年12月

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    記述言語:英語  

  53. Analysis software for upper atmospheric data developed by the IUGONET project and its application to polar science 査読有り

    Tanaka, Y.-M, A. Shinbori, T. Hori, Y. Koyama, S. Abe, N. Umemura, Y. Sato, M. Yagi, S. UeNo, A. Yatagai, Y. Ogawa, Y. Miyoshi  

    Advances in Polar Science, 24, 231-240, doi:10.3724/SP.J.1085.2013.00231   頁: .   2013年12月

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    記述言語:英語  

  54. 全球地磁気データから推察される磁気嵐時の電離圏電流分布の時間・空間変動

    新堀淳樹, 堀智昭, 田中良昌, 小山幸伸, 菊池崇, 長妻努  

    第4回極域科学シンポジウム   2013年11月

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    記述言語:日本語  

  55. 地磁気変動に見られる磁気嵐時のグローバルな電離圏電流分布

    新堀淳樹, 堀智昭, 田中良昌, 小山幸伸, 菊池崇, 長妻努  

    地球電磁気・地球惑星圏学会 第134回総会及び講演会   2013年11月

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    記述言語:日本語  

  56. Characteristics of long-term variation in the upper atmosphere as seen in the geomagnetic solar quiet (Sq) daily variation

    Shinbori, A, Y. Koyama, M. Nose, T. Hori, Y. Otsuka, A. Yatagai  

    International CAWSES-II Symposium   2013年11月

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    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)  

  57. IUGONET プロジェクトチーム, "地磁気日変動の振幅から推察される超高層大気の長期変動について

    新堀淳樹, 小山幸伸, 能勢正仁, 堀智昭, 大塚雄一, 谷田貝亜紀代  

    平成25年度国立極地研究所研究集会   2013年8月

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    記述言語:日本語  

  58. IUGONETデータ解析システム(MDDB/UDAS)が切り開くサイエンス

    新堀淳樹, 八木学, 田中良昌, 佐藤由佳, 堀智昭, 上野悟, 小山幸伸, 谷田貝亜紀代, 阿部修司, IUGONET, プロジェクトチーム  

    平成25年度国立極地研究所研究集会   2013年8月

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    記述言語:日本語  

  59. Contribution of the IUGONET Data Exchange System and Data Analysis Software to Space Weather and Climatology Researches 査読有り

    Shinbori, A, N. V. Rao, T. Tsuda  

    Asia Oceania Geoscience Society 2013   2013年6月

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    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)  

  60. 磁気赤道-低緯度域における磁気急始(SC)の磁場振幅の季節変化について

    新堀淳樹, 小山幸伸, 菊池崇, 荒木徹, 池田昭大, 魚住禎司, Rola, Emerito S. Otadoy, 歌田久司, 長妻努, 湯元清文  

    日本地球惑星科学連合2013年大会   2013年5月

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    記述言語:日本語  

  61. 地磁気静穏日変化に見られる超高層大気の長期変動について

    新堀淳樹, 小山幸伸, 能勢正仁, 谷田貝亜紀代, 堀智昭, 大塚雄一  

    日本地球惑星科学連合2013年大会   2013年5月

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    記述言語:日本語  

  62. IUGONETメタデータ登録・管理システムの処理性能評価 査読有り

    堀智昭, 梅村宜生, 阿部修司, 小山幸伸, 田中良昌, 林寛生, 林寛生, 上野悟, 新堀淳樹, 佐藤由佳, 八木学  

    宇宙航空研究開発機構研究開発報告 JAXA-RR- ( 12-006 ) 頁: 71-78   2013年3月

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    記述言語:日本語  

    J-GLOBAL

  63. IUGONET解析ソフトウェアの現状と今後の発展 査読有り

    田中 良昌, 新堀 淳樹, 梅村 宜生, 堀 智昭, 阿部 修司, 小山 幸伸, 林 寛生, 上野 悟, 佐藤 由佳, 谷田貝 亜紀代, 小川 泰信, 三好 由純, 関 華奈子, 宮下 幸長, 瀬川 朋紀  

    宇宙航空研究開発機構研究開発報告12 巻 ( 12-006 ) 頁: 63-70   2013年3月

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    記述言語:日本語  

    大学間連携プロジェクト「超高層大気長期変動の全球地上ネットワーク観測・研究」(IUGONET)では,IUGONET参加機関である東北大学,名古屋大学,京都大学,九州大学および国立極地研究所の5 機関が所有する多種多様な超高層大気データを可視化・解析できるデータ解析ソフトウェアUDAS(iUgonet Data Analysis Software)を開発している.UDAS は,IDL 言語で書かれたTHEMIS ミッションのデータ解析ソフトウェアTDAS(THEMIS Data Analysis Software suite)のプラグインソフトであり,TDAS が持つ様々な時系列データの可視化・解析ツールやGUI 機能を利用することができる.我々は,2011 年5 月よりIUGONET ウェブベージにおいてUDAS のβ バージョンの公開を開始し,2012 年2月に本公開を開始した.2012 年10 月以降には,UDAS をTDAS に組み込み,THEMIS ソフトウェアウェブサイトから公開することを計画している.UDAS を提供するにあたり,プログラムの動作確認作業を軽減するためのテストツールの開発も行った.さらに,IDL ライセンスを持たない研究者のために,IDL Virtual Machine 環境で走るTDAS の実行ファイルを開発し,テスト公開を開始した.これらの新しい展開により,UDAS 及びIUGONET 所属機関が所有する地上観測データの利用が促進されることが期待される.

    J-GLOBAL

  64. IUGONETメタデータデータベース、および統計解析システムを用いた太陽地球環境変動の研究

    新堀淳樹, 田中良昌, 浜口良太, 堀智昭, 小山幸伸, 阿部修司, 佐藤由佳  

    H24太陽地球環境研究所研究集会「緯度間結合の大気科学」   2013年3月

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    記述言語:日本語  

  65. 地磁気日変化に見られる超高層大気の長期変動について

    新堀淳樹, 浜口良太, 小山幸伸, 能勢正仁, 堀智昭, 大塚雄一, 谷田貝亜紀代  

    電磁圏物理学シンポジウム   2013年3月

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    記述言語:日本語  

  66. 地磁気静穏日変化の長期変動について

    新堀淳樹, 浜口良太, 小山幸伸, 能勢正仁, 谷田貝亜紀代, 堀智昭, 大塚雄一, 浅井歩, 上野悟, 磯部洋明, 横山正樹  

    太陽研究シンポジウム「活動極大期の太陽研究、そして新たな太陽研究への布石」   2013年2月

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    記述言語:日本語  

  67. 太陽活動と高層大気の長期変化(地球側)

    新堀淳樹, 林寛生, 上野悟, 磯部洋明, 浅井歩, 横山正樹  

    第160回生存圏シンポジウム 第3回宇宙環境・利用シンポジウム「太陽活動と地球・惑星大気」   2012年12月

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    記述言語:日本語  

  68. Evolution of negative SI-induced ionospheric flows observed by SuperDARN King Salmon HF radar 査読有り

    T. Hori, A. Shinbori, N. Nishitani, T. Kikuchi, S. Fujita, T. Nagatsuma, O. Troshichev, K. Yumoto, A. Moiseyev, K. Seki  

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS117 巻 ( 12 )   2012年12月

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    記述言語:英語  

    The spatial evolution of vortex-like flow structures induced by a negative sudden impulse (SI-) is studied on the basis of SuperDARN King Salmon HF radar (KSR) with other ground and satellite data. A large dip in the solar wind density induced a fairly large SI- with a SYM-H amplitude of similar to 40 nT. The SI- induced ionospheric flow signatures in the evening sector (MLT similar to 19 h) were observed by KSR as a westward flow associated with the preliminary impulse (PI) followed by a more intense eastward flow with the main impulse (MI) in the sub-auroral region of the magnetic latitude similar to 60-70 deg, consistent with the local ground magnetic field observations. Following the first PI-MI flow sequence, KSR saw a second and possibly third sequence of flow variation which were much smaller in flow amplitude than the first pair but showed qualitatively very similar flow variations and latitudinal/longitudinal propagation characteristics. These observations can be interpreted as aftershocks of the first PI-MI; the same sequence of vortices and field-aligned currents were generated and then drifted anti-sunward with the same mechanism, namely the pumping motion of the dayside magnetosphere. These results are qualitatively consistent with predictions suggested by recent numerical simulations. Citation: Hori, T., A. Shinbori, N. Nishitani, T. Kikuchi, S. Fujita, T. Nagatsuma, O. Troshichev, K. Yumoto, A. Moiseyev, and K. Seki (2012), Evolution of negative SI- induced ionospheric flows observed by SuperDARN King Salmon HF radar, J. Geophys. Res., 117, A12223, doi:10.1029/2012JA018093.

    DOI: 10.1029/2012JA018093

    Web of Science

  69. 磁気嵐時の地磁気変動に見られるグローバルな電離圏電場と電流分布について

    新堀淳樹, 田中良昌, 辻裕司, 菊池崇, 小山幸伸, 長妻努, 冨川喜弘, 堤雅基  

    第3回極域科学シンポジウム/第36回極域宙空圏シンポジウム   2012年11月

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    記述言語:日本語  

  70. Storm-time electron density enhancement in the cleft ion fountain 査読有り

    N. Kitamura, Y. Nishimura, M. O. Chandler, T. E. Moore, N. Terada, T. Ono, A. Shinbori, A. Kumamoto  

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS117 巻 ( 11 )   2012年11月

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    記述言語:英語  

    To determine the characteristics and origin of observed storm-time electron density enhancements in the polar cap, and to investigate the spatial extent (noon-midnight direction) of associated O+ ion outflows, we analyzed nearly simultaneous observations of such electron density enhancements from the Akebono satellite and ion upflows from the Polar satellite during a geomagnetic storm occurring on 6 April 2000. The Akebono satellite observed substantial electron density enhancements by a factor of similar to 10-90 with a long duration of similar to 15 h at similar to 2 R-E in the southern polar region. The Polar satellite outflow measurements in the northern polar cap at similar to 7-4 R-E exhibited velocity filtering of the similar to 100 eV to similar to 0 eV (from the spacecraft potential) ion outflow from the cleft ion fountain, with resultant temperatures declining from similar to 3 eV to 0.03 eV with increasing distance from the cusp. Similar velocity filtering was detected in the southern polar cap at similar to 1.8-3.5 RE. The region of O+ ion outflows with fluxes exceeding 5 x 10(8) /cm(2)/s (mapped to 1000 km altitude) extended similar to 10 degrees MLAT (similar to 1000 km) at the ionosphere from the cusp/cleft into the dayside polar cap at similar to 2.5 RE. These coordinated Akebono-Polar observations are consistent with the development of storm-time electron density enhancements in the polar cap as a result of the bulk outflow of low-energy plasma as part of the cleft ion fountain. The large spatial scale, large ion fluxes, and the long duration indicate significant supply of very-low-energy O+ ions to the magnetosphere through this region.

    DOI: 10.1029/2012JA017900

    Web of Science

  71. Effect of R2-FAC development on the ionospheric electric field pattern deduced by a global ionospheric potential solver

    Nakamizo Aoi, Hiraki Yasutaka, Ebihara Yusuke, Kikuchi Takashi, Seki Kanako, Hori Tomoaki, Ieda Akimasa, Miyoshi Yoshizumi, Tsuji Yuji, Nishimura Yukitoshi, Shinbori Atsuki  

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS117 巻   2012年9月

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    記述言語:英語  

    DOI: 10.1029/2012JA017669

    Web of Science

  72. IUGONETプロダクトを用いた太陽風-磁気圏-電離圏-大気圏結合の研究

    新堀淳樹, 八木学, 田中良昌, 佐藤由佳, 堀智昭, 上野悟, 小山幸伸, 能勢正仁, 谷田貝亜紀代, 橋口典子, 阿部修司, IUGONET, プロジェク トチーム  

    第8回磁気圏-電離圏複合系における対流に関する研究会プログラム   2012年9月

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    記述言語:日本語  

  73. Upper atmospheric research using the metadata database and integrated data analysis software (UDAS) developed by the IUGONET project 査読有り

    Shinbori, A, Y. Koyama, T. Hori, Y. Tanaka, S. Abe, S. UeNo, N. O. Hashiguchi, N. Umemura, Y. Sato, M. Yagi, A. Yatagai, IUGONET project team  

    HSS2012   2012年8月

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    記述言語:英語  

  74. IUGONET プロジェクトチーム, "IUGONETプロダクトを用いた電離圏・熱圏・中間圏研究

    新堀淳樹, 八木学, 田中良昌, 佐藤由佳, 堀智昭, 上野悟, 小山幸伸, 谷田貝亜紀代, 橋口典子, 阿部修司  

    電離圏・熱圏・中間圏研究会   2012年8月

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    記述言語:日本語  

  75. Magnetic local time and latitude dependence of amplitude of the main impulse (MI) of geomagnetic sudden commencements and its seasonal variation 査読有り

    Atsuki Shinbori, Yuji Tsuji, Takashi Kikuchi, Tohru Araki, Akihiro Ikeda, Teiji Uozumi, Dmitry Baishev, Boris M. Shevtsov, Tsutomu Nagatsuma, Kiyohumi Yumoto  

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS117 巻 ( 8 )   2012年8月

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    記述言語:英語  

    The magnetic local time and latitude dependence of amplitude of the main impulse (MI) of geomagnetic sudden commencements (SCs) and its seasonal variation have been investigated using high time resolution (1-3 sec) geomagnetic data in the latitudinal range 27-70 degrees for the period 1996-2010. The daytime distribution of the SC-MI amplitude in the sub-auroral and middle latitudes (35-60 degrees) is similar to the DP-2 type geomagnetic variation which shows negative and positive changes in the morning and afternoon, respectively. The magnetic field variation is reversed around the magnetic latitude of 63-65 degrees. This suggests that a pair of field-aligned currents (FACs), resembling the region-1 (R-1) FACs, is located near the magnetic latitude of 63-65 degrees. The nighttime SC amplitude is enhanced significantly in the low and middle latitudes (27-60 degrees). The enhancement is due to the magnetic effect produced by the SC-MI FACs. In the nighttime auroral latitude (63-65 degrees), the SC amplitude decreases steeply due to the enhanced westward auroral electrojet associated with the compression of the magnetosphere. The size of the diurnal variation tends to increase significantly during the summer, compared with that during the winter. This seasonal variation suggests that the DP-2 type ionospheric currents (ICs) and FACs generated during the SC-MI phase are intensified by increased ionospheric conductivities during the summer. It can be concluded that the large-scale MI current system in the ionosphere and magnetosphere is voltage generator.

    DOI: 10.1029/2012JA018006

    Web of Science

  76. IUGONETサイエンスタスクチームの活動報告

    新堀淳樹, 八木学, 田中良昌, 佐藤由佳, 堀智昭, 上野悟, 小山 幸伸, 谷田貝亜紀代, 阿部修司, IUGONETプロジェクトチーム  

    平成24年度IUGONET中間報告会   2012年8月

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    記述言語:日本語  

  77. Magnetic latitude and local time distributions of ionospheric currents during a geomagnetic storm 査読有り

    Yuji Tsuji, Atsuki Shinbori, Takashi Kikuchi, Tsutomu Nagatsuma  

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS117 巻 ( 7 )   2012年7月

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    記述言語:英語  

    In order to clarify the global distribution of ionospheric currents during a geomagnetic storm, we analyzed ground magnetic disturbances from high latitudes to the magnetic equator for the storm on September 7-8, 2002, with the minimum SYM-H value of -168 nT. In this analysis, we investigated magnetic field deviations in the northward component from the SYM-H, as functions of the dipole magnetic latitude (DMLAT) and the magnetic local time (MLT). During the main phase of the storm, the deviations at the low latitudes (10 degrees-35 degrees in DMLAT) were positive/negative in the dawn/dusk (0-9/11-24 h MLT) sector. On the other hand, the deviations at the dayside middle latitudes (35 degrees-55 degrees in DMLAT) were negative/positive in the morning/afternoon (6-12/13-15 h MLT) sector. The local time distribution at the low latitudes may represent the dawn-dusk asymmetry of the storm time ring current, while that at the dayside middle latitudes coincides with the DP2 currents due to the convection electric field associated with the Region 1 field-aligned currents (R1 FACs). All over the nightside middle latitude, the deviations were positive. This implies the direct effect of the R1 FACs through the Biot-Savart's law. At the geomagnetic equator, the eastward and westward electrojets were intensified on the day and nightside, respectively, being caused by the penetrated dawn-to-dusk convection electric field. We found that the MLT distribution of the magnetic deviations during the recovery phase was in opposite sense to that during the main phase at the dayside middle latitudes. The reversed magnetic disturbances must be due to the overshielding electric field associated with the Region 2 field-aligned currents (R2 FACs). Similarly, the deviations at the dayside and nightside equator were reversed, indicating penetration of the dusk-to-dawn overshielding electric field into the equatorial ionosphere. Based on the above results, we propose a current system including the ionospheric currents at middle latitudes caused by the R1/R2 FACs, equatorial EEJ/CEJ, and asymmetric ring current, during the main/recovery phase of the geomagnetic storm.

    DOI: 10.1029/2012JA017566

    Web of Science

  78. Temporal and spatial evolution of ionospheric currents and electric fields during a geomagnetic storm

    Shinbori, A, Y. Nishimura, Y. Tsuji, T. Kikuchi, T. Nagatsuma, IUGONET project team  

    GEM Workshop 2012   2012年6月

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    記述言語:英語  

  79. IUGONET プロジェクトチーム, "地磁気静穏日変化(Sq)の長期トレンドから推察される超高層大気変動について

    新堀淳樹, 小山幸伸, 能勢正仁, 林寛生, 堀智昭, 大塚雄一, 浅井歩, 磯部洋明, 横山正樹, 上野悟, 塩田大幸, 羽田裕子, 北井礼三郎, 津田敏隆  

    日本地球惑星科学連合2012年大会   2012年5月

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    記述言語:日本語  

  80. 大学間連携プロジェクト「超高層大気長期変動の全球地上ネットワーク観測・研究」 査読有り

    林寛生, 小山幸伸, 堀智昭, 田中良昌, 新堀淳樹, 鍵谷将人, 阿部修司, 河野貴久, 吉田大紀, 上野悟, 金田直樹, 米田瑞生, 田所裕康, 元場哲郎  

    宇宙航空研究開発機構研究開発報告 JAXA-RR- ( 11-007 ) 頁: 113-120   2012年3月

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    記述言語:日本語  

    J-GLOBAL

  81. IUGONET共通メタデータフォーマットの策定とメタデータ登録管理システムの開発 査読有り

    堀智昭, 鍵谷将人, 田中良昌, 林寛生, 上野悟, 吉田大紀, 阿部修司, 小山幸伸, 河野貴久, 金田直樹, 新堀淳樹, 田所裕康, 米田瑞生  

    宇宙航空研究開発機構研究開発報告 JAXA-RR- ( 11-007 ) 頁: 105-111   2012年3月

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    記述言語:日本語  

    J-GLOBAL

  82. 超高層物理学分野の為のメタデータ・データベースの開発 査読有り

    小山幸伸, 河野貴久, 堀智昭, 阿部修, 吉田大紀, 林寛生, 田中良昌, 新堀淳樹, 上野悟, 金田直樹, 米田瑞生, 元場哲郎, 鍵谷将人, 田所裕康  

    宇宙航空研究開発機構研究開発報告 JAXA-RR- ( 11-007 ) 頁: 99-104   2012年3月

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    記述言語:日本語  

    J-GLOBAL

  83. IUGONET解析ソフトウェアの開発 査読有り

    田中良昌, 新堀淳樹, 鍵谷将人, 堀智昭, 阿部修司, 小山幸伸, 林寛生, 吉田大紀, 河野貴久, 上野悟, 金田直樹, 米田瑞生, 田所裕康, 元場哲郎, 三好由純, 関華奈子, 宮下幸長, 瀬川朋紀, 小川泰信  

    宇宙航空研究開発機構研究開発報告 JAXA-RR- ( 11-007 ) 頁: 91-98   2012年3月

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    記述言語:日本語  

    J-GLOBAL

  84. 平成24年度のIUGONETサイエンスタスクチームの活動報告と地磁気日変化の振幅に見られる超高層大気の長期変動

    新堀淳樹, 小山幸伸, 林寛生, 能勢正仁, 大塚雄一, 堀智昭, IUGONET, プロジェクトチーム  

    名古屋大学太陽地球環境研究所研究集会「地球科学メタ情報データベースの現状とその活用」   2012年2月

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    記述言語:日本語  

  85. Long-term Variation in the Upper Atmosphere as Seen in the Amplitude of the Geomagnetic Solar Quiet Daily Variation

    Shinbori, A, Y. Koyama, H. Hayashi, M. Nose, T. Hori, Y. Otsuka, T. Tsuda, H. Hiroo, IUGONET Project Team  

    The 2nd Nagoya Workshop on the Relationship between Solar Activity and Climate Changes   2012年1月

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    記述言語:英語  

  86. 太陽活動と地磁気静穏日変化との長期的な関係について

    新堀淳樹, 小山幸伸, 能勢正仁, 林寛生, 堀智昭, 大塚雄一, 浅井歩, 上野悟, 磯部洋明, 横山正樹  

    太陽研究会「太陽の多角的観測と宇宙天気研究の新展開2012   2012年1月

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    記述言語:日本語  

  87. 地磁気日変化の振幅に見られる超高層大気の長期変動について

    新堀淳樹, 小山幸伸, 林寛生, 能勢正仁, 堀智昭, 大塚雄一  

    第7回磁気圏電離圏複合系における対流に関する研究会集録   2012年1月

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    記述言語:日本語  

  88. 磁気嵐時におけるグローバルな地磁気変動と電離圏擾乱ダイナモについて

    新堀淳樹, 田中良昌, 辻裕司, 菊池崇, 小山幸伸, 林寛生, 冨川喜弘, 長妻努, 堤雅基, Dennis M. Riggin, Dave C. Fritts, Peter Hoffmann, IUGONETプロジェクトチーム  

    第2回極域科学シンポジウム・第35回極域宙空圏シンポジウム   2011年11月

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    記述言語:日本語  

  89. 高緯度から磁気赤道域までの磁気急始 (SC) の磁場振幅の季節変化の緯度依存性

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 池田昭大, 魚住禎司, Baishev Dmitry, Shevtsov Boris M, Otadoy Rola, E. S, 歌田久司, 長妻努, 湯元清文, IUGONETプロジェクトチーム  

    地球電磁気・地球惑星圏学会 第130回講演会   2011年11月

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    記述言語:日本語  

  90. 磁気嵐時におけるグローバル地磁気変動と熱圏風変動について

    新堀淳樹, 田中良昌, 辻裕司, 菊池崇, 林寛生, 冨川喜弘, 長妻努, 堤雅基, IUGONETプロジェクトチーム  

    磁気圏-電離圏複合系における対流に関する研究会   2011年9月

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    記述言語:日本語  

  91. Solar zenith angle dependence of plasma density and temperature in the polar cap ionosphere and low-altitude magnetosphere during geomagnetically quiet periods at solar maximum 査読有り

    N. Kitamura, Y. Ogawa, Y. Nishimura, N. Terada, T. Ono, A. Shinbori, A. Kumamoto, V. Truhlik, J. Smilauer  

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS116 巻 ( 8 )   2011年8月

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    記述言語:英語  

    We constructed an empirical model of the electron density profile with solar zenith angle (SZA) dependence in the polar cap during geomagnetically quiet periods using 63 months of Akebono satellite observations at solar maximum. The electron density profile exhibits a transition at similar to 2000 km altitude only under dark conditions. The electron density and scale height at low altitudes change drastically, by factors of 25 (at 2300 km altitude) and 2.0, respectively, as the SZA increases from 90 degrees to 120 degrees. The SZA dependence of the ion and electron temperatures is also investigated statistically on the basis of data obtained by the Intercosmos satellites and European Incoherent Scatter (EISCAT) Svalbard radar (ESR). A drastic change in the electron temperature occurs near the terminator, similarly to that in the electron density profile obtained by the Akebono satellite. The sum of the ion and electron temperatures obtained by the ESR (similar to 6500 K at similar to 1050 km altitude under sunlit conditions and similar to 3000 K at similar to 750 km altitude under dark conditions) agrees well with the scale height at low altitudes obtained from the Akebono observations, assuming that the temperature is constant and that O(+) ions are dominant. Comparisons between the present statistical results (SZA dependence of the electron density and ion and electron temperatures) and modeling studies of the polar wind indicate that the plasma density profile (especially of the O(+) ion density) in the polar cap is strongly controlled by solar radiation onto the ionosphere by changing ion and electron temperatures in the ionosphere during geomagnetically quiet periods.

    DOI: 10.1029/2011JA016631

    Web of Science

  92. Seasonal dependence of geomagnetic field variations on the ground associated with geomagnetic sudden commencements 査読有り

    Shinbori, A, Y. Tsuji, T. Kikuchi, T. Araki, A. Ikeda, T. Uozumi, S. I. Solovyev, B. M. Shevtsov, R. E, S. Otadoy, H. Utada, T. Nagatsuma, H. Hayashi, K. Yumoto, IUGONET project team  

    XXV IUGG General Assembly   2011年7月

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    記述言語:英語  

  93. IUGONET 観測データに基づく地磁気静穏日変化と熱圏風の長期変動について

    新堀淳樹, 小山幸伸, 林寛生, 能勢正仁, 津田敏隆, IUGONET, プロジェクトチーム  

    日本地球惑星科学連合2011年大会   2011年5月

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    記述言語:日本語  

  94. Development of integrated analysis software of observation data in the upper atmosphere

    Shinbori, A, Y. Tanaka, M. Kagitani, H. Hayashi  

    ecent Advances in Observational Studies of the Tropical Atmosphere and Ionosphere   2011年3月

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    記述言語:英語  

  95. Long-term analysis of geomagnetic solar quiet daily (Sq) variation and neutral winds in the mesosphere and lower thermosphere (MLT) region using the IUGONET observation data

    Shinbori, A, H. Hayashi, Y. Koyama, S. Nose, S. Ueno, H. Isobe, A. Asai, M. Yokoyama  

    Recent Advances in Observational Studies of the Tropical Atmosphere and Ionosphere   2011年3月

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    記述言語:英語  

  96. 高緯度から磁気赤道域における磁気急始(SC)の磁場振幅の季節依存性について

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 池田昭大, 魚住禎司, S. I. Solovyev, Boris M. Shevtsov, Rol, Emerito S. Otadoy, 歌田久司, 長妻努, 湯元清文, IUGONETプロジェクトチーム  

    名古屋大学太陽地球環境研究所・研究集会「電磁圏物理学シンポジウム」   2011年3月

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    記述言語:日本語  

  97. IUGONET観測データに基づく地磁気日変化と熱圏風の長期トレンドについて

    新堀淳樹, 林寛生, 小山幸伸, 能勢正仁, 上野悟, 磯部洋明, 浅井歩, 横山正樹  

    名古屋大学太陽地球環境研究所研究集会『地球科学メタ情報データベースの現状とその活用』   2011年2月

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    記述言語:日本語  

  98. Penetration of Magnetospheric Electric Fields to the Low Latitude Ionosphere During Storm/Substorms 査読有り

    Kikuchi, T, K. K. Hashimoto, A. Shinbori, Y. Tsuji, S. Watari  

    Aeronomy of the Earth's Atmosphere and Ionosphere IAGA Special Sopron Book Series 2, DOI: 10.1007/978-94-007-0326-1_34, Edit. M.A. Abdu, D.Pancheva, A. Bhattacharyya, Springer Science+Business Media B.V.2 巻   頁: 443-453   2011年2月

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    記述言語:英語  

  99. IUGONETデータベースを利用した生存圏科学萌芽研究"

    新堀淳樹, 林寛生, 上野悟, 磯部洋明, 浅井歩, 横山正樹  

    太陽研究会「太陽の多角的観測と宇宙天気研究の新展開2011」   2011年1月

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    記述言語:日本語  

  100. DSpaceを用いた超高層物理学のためのメタデータ・データベースの構築

    河野貴久, 小山幸伸, 堀智昭, 阿部修司, 吉田大紀, 林寛生, 新堀淳樹, 田中良昌, 鍵谷将人, 金田直樹, 田所裕康  

    第3回データ工学と情報マネジメントに関するフォーラム論文集, C8-5   2011年

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    記述言語:日本語  

  101. Direct measurements of the Poynting flux associated with convection electric fields in the magnetosphere 査読有り

    Y. Nishimura, T. Kikuchi, A. Shinbori, J. Wygant, Y. Tsuji, T. Hori, T. Ono, S. Fujita, T. Tanaka  

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS115 巻 ( 12 )   2010年12月

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    記述言語:英語  

    Observations of Poynting fluxes associated with onset of convection electric fields are essential for understanding of electromagnetic energy transport from the solar wind toward the magnetosphere leading to changes in the convection electric field, which is one of the most fundamental parameters in the magnetosphere-ionosphere coupled system. We present Cluster multispacecraft observations of Poynting fluxes associated with abrupt changes in large-scale electric fields during sudden commencements and southward turning of the interplanetary magnetic field (IMF). The Cluster spacecraft detected Poynting fluxes dominated by the field-aligned upward component during the preliminary impulse of sudden commencements and in the initial period after southward turning of the IMF. The upward Poynting flux indicates existence of Alfven waves transporting electromagnetic energy from the ionosphere toward the magnetosphere leading to magnetospheric convection changes. The waveguide model and global magnetohydrodynamic (MHD) simulation calculating evolution of the Poynting flux following solar wind pressure enhancements also show upward Poynting fluxes propagating from the ionosphere toward the magnetosphere faster than the propagation of compressional waves. We conclude that the ionosphere acts as a channel to transmit electromagnetic energy supplied as field-aligned currents toward a wide region in the magnetosphere-ionosphere system instantaneously, leading to changes in magnetospheric convection electric fields.

    DOI: 10.1029/2010JA015491

    Web of Science

  102. 磁気嵐時におけるグローバルな地磁気変動

    新堀淳樹, 西村幸敏, 辻裕司, 菊池崇, 長妻努, 亘慎一, IUGONETメンバー  

    第34回極域宙空圏シンポジウム   2010年12月

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    記述言語:日本語  

  103. Observations of very-low-energy (&lt; 10 eV) ion outflows dominated by O+ ions in the region of enhanced electron density in the polar cap magnetosphere during geomagnetic storms 査読有り

    N. Kitamura, Y. Nishimura, T. Ono, Y. Ebihara, N. Terada, A. Shinbori, A. Kumamoto, T. Abe, M. Yamada, S. Watanabe, A. Matsuoka, A. W. Yau  

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS115 巻 ( 11 )   2010年11月

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    記述言語:英語  

    Velocity distributions of upflowing ions in the polar ionosphere are crucial to understand their destinations. Natural plasma wave observations by the plasma wave and sounder experiments and thermal ion observations by the suprathermal ion mass spectrometer onboard the Akebono satellite at similar to 9000 km altitude in the polar magnetosphere during the geomagnetic storms showed that ions in the region of enhanced electron density in the polar cap were dominated by very-low-energy O+ ions (similar to 85%) with upward velocities of 4-10 km s(-1), corresponding to streaming energies of 1.3-8.4 eV. The fluxes of very-low-energy upflowing O+ ions exceeded 1 x 10(9) cm(-2) s(-1) (mapped to 1000 km altitude) across wide regions. These signatures are consistent with high-density plasma supplied by the cleft ion fountain mechanism. Trajectory calculations of O+ ions based on the Akebono observations as the initial condition showed the transport paths and accelerations of the O+ ions and indicated that the velocities of the very-low-energy upflowing O+ ions through the dayside polar cap are enough to reach the magnetosphere under strong convection. The calculations suggest the importance of the very-low-energy upflowing O+ ions with large fluxes in the total O+ ion supply toward the magnetosphere, especially the near-Earth tail region and inner magnetosphere. The initially very-low-energy O+ ions can contribute significantly to the ring current formation during geomagnetic storms since some of the O+ ions were transported into the ring current region with typical energies of ring current ions (several tens of keV) in the trajectory calculations.

    DOI: 10.1029/2010JA015601

    Web of Science

  104. IUGONET観測データに基づく赤道域における磁気急始(SC)の磁場振幅の季節依存性

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 林寛生, 津田敏隆, 池田昭大, 魚住禎司, R. E, S. Otadoy, 歌田久司, B. M. Shevtsov, S. I. Solovyev, 長妻努, 湯元清文, IUGONETプロジェクトチーム  

    平成22年度・第1回STE(太陽地球環境)現象報告会   2010年10月

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  105. Anomalous Enhancement of Occurrence of the Preliminary Impulse of Geomagnetic Sudden Commencement (SC) at Low Latitude in the South Atlantic Anomaly (SAA) region 査読有り

    Shinbori A, Y. Nishimura, Y. Tsuji, T. Kikuchi, T. Araki, A. Ikeda, T. Uozumi, R. Otadoy, H. Utada, J. Ishitsuka, N. Trivedi, S. Dutra, N. Schuch, S. Watari, T. Nagatsuma, K. Yumoto  

    Journal of Geophysical Research: Space Physics, Volume 115, Issue A8, CiteID: A08309, doi: 10.1029/2009JA015035115 巻 ( A8 ) 頁: .   2010年8月

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    記述言語:英語  

  106. Characteristics of enhanced convection electric field in the inner magnetosphere associated with sudden commencements observed by the Akebono Satellite 査読有り

    Shinbori, A, Y. Nishimura, T. Kikuchi, T. Araki, A. Matsuoka, Y. Tsuji  

    38th COSPAR Scientific Assembly   2010年7月

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    記述言語:英語  

  107. ブラジル磁気異常帯における磁気急始(SC)時の初期インパルスの異常な出現特性について

    2010年大会   2010年5月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  108. 磁気嵐時におけるグローバル地磁気変動

    新堀 淳樹, 西村幸敏, 辻裕司, 菊池崇, 長妻努, 亘慎一  

    日本地球惑星科学連合2010大会   2010年5月

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    記述言語:日本語  

  109. Penetration of magnetospheric electric fields to the equator and their effects on the low-latitude ionosphere during intense geomagnetic storms 査読有り

    B. Veenadhari, S. Alex, T. Kikuchi, A. Shinbori, Rajesh Singh, E. Chandrasekhar  

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS115 巻 ( A3 )   2010年3月

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    記述言語:英語  

    The penetration of magnetospheric electric fields to the magnetic equator has been investigated for two intense magnetic storms that occurred on 31 March 2001 and 6 November 2001. The digital ground magnetic data from equatorial station Tirunelveli (TIR, 0.17 degrees S geomagnetic latitude (GML)) and low-latitude station Alibag (ABG, 10.17 degrees N GML) have been used to identify the storm time electrojet index, EEJ(Dis), which is the difference of the magnetic field variations between TIR and ABG after removing the quiet day variations. The appearance of enhanced DP 2 currents and counterelectrojets (CEJ) during the main and recovery phases of the magnetic storms is possibly due to prompt penetration of electric fields from the high latitudes. These signatures can be interpreted as a clear indicator of the eastward and westward electric fields at the equator. The observed results suggest that the magnitude of the equatorial ionospheric currents driven by the penetrating electric fields is very sensitive to ionospheric conductivity (which depends on local time). Moreover, the intensity of the DP 2 currents started decreasing during the end of the main phase of the storm despite the large negative southward IMF Bz, indicating the dominance of a well-developed shielding electric field for 1 h. As an effect of penetrating electric fields at the equator, the equatorial ionization anomaly is enhanced during the main phase (because of strong eastward electric field) and is inhibited or reduced due to the strong CEJ (because of westward electric field) during the recovery phase.

    DOI: 10.1029/2009JA014562

    Web of Science

  110. 磁気嵐時におけるグローバル地磁気変動について

    新堀淳樹, 西村幸敏, 辻裕司, 菊池崇, 荒木徹, 長妻努, 亘慎一  

    平成21年度・第2回STE(太陽地球環境)現象報告会   2010年3月

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  111. 南米磁気異常帯の低緯度における磁気急始 (SC) 時の初期インパルスの出現増大について

    新堀淳樹, 辻裕司, 西村幸敏, 菊池崇, 荒木徹, 池田昭大, 魚住禎司, Roland E. S. Otadoy, 歌田久司, Jose Ishitsuka・Nalin Baulal Trivedi, Severino L. G. Dutra, Nelson Jorge Schuch, 亘慎一, 長妻努, 湯元清文  

    電磁圏物理学シンポジウム   2010年3月

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    記述言語:日本語  

  112. 現実に即した高さ方向の電気伝導度の導出法の開発

    新堀淳樹, 西村幸敏, 海老原祐輔, 菊池崇, 平木康隆, 堀智昭  

    GEMSIS-M,I ワークショップ「実証型ジオスペースモデリングに向けて」   2010年2月

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    記述言語:日本語  

  113. 磁気嵐時のグローバル電流系と地磁気変動

    新堀淳樹, 西村幸敏, 辻裕司, 菊池崇, 海老原祐輔, 長妻努, 亘慎一  

    GEMSIS-M,I ワークショップ「実証型ジオスペースモデリングに向けて」   2010年2月

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    記述言語:日本語  

  114. 太陽風IMFの方位に対するSC振幅の日変化の依存性

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 池田昭大, 魚住禎司, 亘慎一, 長妻努, 湯元清文  

    平成21年度名古屋大学太陽地球環境研究所研究集会「第5回磁気圏-電離圏複合系における対流に関する研究会」   2009年11月

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  115. 多圏間相互作用に対する太陽風動圧の役割

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 池田昭大, 魚住禎司, 湯元清文  

    STE研究連絡会現象解析ワークショップ~システムとしての磁気嵐・サブストーム~   2009年10月

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    記述言語:日本語  

  116. Response of convection electric fields in the magnetosphere to IMF orientation change 査読有り

    Y. Nishimura, T. Kikuchi, J. Wygant, A. Shinbori, T. Ono, A. Matsuoka, T. Nagatsuma, D. Brautigam  

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS114 巻 ( 9 )   2009年9月

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    記述言語:英語  

    The transient response of convection electric fields in the inner magnetosphere to southward turning of the interplanetary magnetic field (IMF) is investigated using in-situ electric field observations by the CRRES and Akebono spacecraft. Electric fields earthward of the inner edge of the electron plasma sheet show quick responses simultaneously with change in ionospheric electric fields, which indicates the arrival of the first signal related to southward turning. A coordinated observation of the electric field by the CRRES and Akebono spacecraft separated by 5 RE reveals a simultaneous increase in the dawn-dusk electric field in a wide region of the inner magnetosphere. A quick response associated with the southward turning of the IMF is also identified in in-situ magnetic fields. It indicates that the southward turning of the IMF initiates simultaneous (less than 1 min) enhancements of ionospheric electric fields, convection electric fields in the inner magnetosphere, and the ring or tail current and region 2 FACs. In contrast, a quick response of convection electric fields is not identified in the electron plasma sheet. A statistical study using 161 events of IMF orientation change in 1991 confirms a prompt response within 5 min for 80% of events earthward of the electron plasma sheet, while a large time lag of more than 30 min is identified in electric fields in the electron plasma sheet. The remarkable difference in the response of electric fields indicates that electric fields in the electron plasma sheet are weakened by high conductance in the magnetically conjugated auroral ionosphere.

    DOI: 10.1029/2009JA014277

    Web of Science

  117. 中緯度から低緯度における磁気急始 (SC) の振幅の日変化の季節依存性

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 亘慎一  

    日本地球惑星科学連合2009年大会   2009年5月

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  118. サブオーロラ帯から磁気赤道における磁気急始(SC)に伴う地上磁場変動の特徴とその解釈について

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 亘慎一  

    日本地球惑星科学連合2009年大会, 招待講演   2009年5月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  119. Magnetic latitude and local time dependence of the amplitude of geomagnetic sudden commencements 査読有り

    Atsuki Shinbori, Yuji Tsuji, Takashi Kikuchi, Tohru Araki, Shinichi Watari  

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS114 巻 ( 4 )   2009年4月

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    記述言語:英語   出版者・発行元:AMER GEOPHYSICAL UNION  

    Statistical analysis of the main impulse (MI) amplitude of geomagnetic sudden commencements (SCs) in a region from the middle latitudes to equator has been made using the long-term geomagnetic field data obtained from the Yap (geomagnetic latitude, theta = 0.38 degrees), Guam (theta = 5.22 degrees), Okinawa (theta = 16.54 degrees), Kakioka (theta = 27.18 degrees), Memanbetsu (theta = 35.16 degrees), and St. Paratunka (theta = 45.58 degrees) stations. The magnetic local time (MLT) dependence of SC amplitude in the middle latitudes showed magnetic field variations produced by two-cell ionospheric currents (DP 2-type currents) which are driven by the dawn-to-dusk electric field accompanying a pair of field-aligned currents (FACs). The effect of the DP 2-type currents at least expands to the low latitude (theta = 16.54 degrees). In this region, the DL part of SC produced by the enhanced Chapman-Ferraro currents can be dominant, but the DP part of SC contaminated 7% of the DL one. On the other hand, at the daytime equator between 8: 00 and 16: 00 (MLT), the SC amplitude is considerably enhanced with its peak amplitude of 3.24 ( normalized SYM-H value) around 11: 00 (MLT) due to the Cowling effect. Another interesting point is that the SC amplitude in the nighttime sector was enhanced at all the stations again, and its peak value increases with increasing magnetic latitude. This result suggests that the effect of the FACs associated with the MI phase of SC expands to the equator.

    DOI: 10.1029/2008JA013871

    Web of Science

  120. 低緯度ブラジル磁気異常帯における磁気急始(SC)の磁場振幅の異常増加について 査読有り

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 亘慎一, M. A. Abdu  

    平成20年度・第2回STE(太陽地球環境)現象報告会   2009年3月

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  121. サブオーロラ帯から磁気赤道にいたる磁気急始(SC)における磁場振幅の季節依存性について

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 亘慎一  

    平成20年度名古屋大学太陽地球環境研究所研究集会「電磁圏物理学シンポジウム」   2009年3月

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  122. Seasonal variations of the electron density distribution in the polar region during geomagnetically quiet periods near solar maximum 査読有り

    N. Kitamura, A. Shinbori, Y. Nishimura, T. Ono, M. Iizima, A. Kumamoto  

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS114 巻 ( 1 )   2009年1月

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    記述言語:英語  

    Meridional electron density distributions above 45 degrees invariant latitude (ILAT) during geomagnetically quiet periods are statistically studied. Electron density data were obtained from plasma waves observed by the Akebono satellite from March 1989 to February 1991 (near solar maximum) in an altitude range of 274-10,500 km. Field-aligned electron density profiles were fitted by the sum of exponential and power law functions. The transition height, where the power law term equals the exponential term, is highest in the summer (at low solar zenith angle (SZA)) at similar to 4000 km and lowest in the winter (at high SZA) at similar to 1800 km in a region of ILAT &gt;= 70 degrees; this is caused by the larger scale height in the summer (similar to 550 km) than that in the winter (similar to 250 km). The largest seasonal variation and SZA dependence of the electron density are found at an altitude of similar to 2000 km with a factor of similar to 50 (similar to 10(4) /cc in the summer, similar to 10(3) /cc in the winter) in the trough, auroral, and polar cap regions. The seasonal variation and SZA dependence are smaller, about a factor of 5-10, above similar to 5000 km. Day-night asymmetries in each season (within a factor of 5) are smaller than the seasonal variation. The scale height is larger in the dayside than in the nightside in each season. These results indicate that photoionization processes in the ionosphere strongly control electron density distributions up to at least similar to 5000 km in the trough, auroral, and polar cap regions.

    DOI: 10.1029/2008JA013288

    Web of Science

  123. IMF/太陽風動圧変動時の内部磁気圏-電離圏電磁結合

    菊池崇, 橋本久美子, 海老原祐輔, 新堀淳樹, 亘慎一  

    第5回磁気圏-電離圏複合系における対流に関する研究会抄録, 1-6   2009年

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  124. ブラジル磁気異常帯における磁気急始(SC)時の磁場変動の特異性と電離圏電気伝導度との関係

    新堀淳樹, 辻裕司, 西村幸敏, 菊池崇, 荒木徹, 池田昭大, 魚住禎司, Rola, d, E. S. Otadoy, 歌田久司, Jose Ishitsuka, Nalin Baulal Trivedi, Severino L, G. Dutra, Nelson Jorge・Schuch, 亘慎一, 長妻務, 湯元清文  

    第5回磁気圏―電離圏複合系における対流に関する研究会収録, 30-55   2009年

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    記述言語:日本語  

  125. 地磁気DP2型変動の考察

    荒木徹, 菊池崇, 新堀淳樹, 湯元清文  

    第5回磁気圏-電離圏複合系における対流に関する研究会抄録, 117-124   2009年

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    記述言語:日本語  

  126. 磁気嵐急始(SC)に伴う磁場変動から理解できること

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 亘慎一  

    平成20年度名古屋大学太陽地球環境研究所研究集会「第4回磁気圏-電離圏複合系における対流に関する研究会」   2008年11月

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    記述言語:日本語  

  127. 磁気嵐時における内部磁気圏電場構造について

    新堀淳樹, 菊池崇, 西村幸敏, 辻裕司, 松岡彩子  

    太陽から地球までシンポジウム   2008年10月

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    記述言語:日本語  

  128. あけぼの衛星観測に基づく磁気急始(SC)に伴う磁気圏対流電場の増大について

    新堀淳樹, 菊池崇, 西村幸敏, 松岡彩子, 辻裕司  

    第124回 地球電磁気・地球惑星圏学会 総会・講演会   2008年10月

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    記述言語:日本語  

  129. SC研究の最前線

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 亘慎一  

    平成20年度・第1回STE(太陽地球環境)現象報告会   2008年9月

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    記述言語:日本語  

  130. あけぼの衛星によって内部磁気圏で観測されるSCに関連した電磁場変動現象

    新堀淳樹, 菊池崇, 小野高幸, 飯島雅英, 熊本篤志, 西村幸敏, 松岡彩子  

    第32回極域宙空圏シンポジウム   2008年8月

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    記述言語:日本語  

  131. Penetration of storm-time electric fields to the middle-latitude ionosphere and inner magnetosphere observed by the magnetometers and Akebono satellite 査読有り

    Shinbori, A, Y. Tsuji, T. Kikuchi, A. Matsuoka  

    COSPAR   2008年7月

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    記述言語:英語  

  132. SC related electric and magnetic field phenomena in the inner magnetosphere observed by the Akebono satellite 査読有り

    Shinbori, A, T. Kikuchi, T. Ono, M. Iizima, A. Kumamoto, Y. Nishimura, A. Matsuoka  

    Asia Oceania Geosciences Society   2008年6月

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    記述言語:英語  

  133. 衛星観測に基づく磁気圏内における SC の磁場振幅の日変化

    新堀淳樹, 菊池崇, 辻裕司, 荒木徹, 西村幸敏, 越石英樹, 松本晴久, 五家建夫  

    日本地球惑星科学連合2008年大会   2008年5月

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    記述言語:日本語  

  134. 磁気急始 (SC) の振幅の日変化への太陽風 IMF 効果とその季節依存性

    新堀淳樹, 菊池崇, 辻裕司, 荒木徹  

    日本地球惑星科学連合2008年大会, 招待講演   2008年5月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  135. 太陽風-磁気圏-電離圏結合過程の基礎理解としての磁気急始(SC)現象の姿

    新堀淳樹, 菊池崇, 辻裕司, 荒木徹  

    平成19年度名古屋大学太陽地球環境研究所研究集会 「第3回ジオスペース環境科学研究会」, 招待講演   2008年3月

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    記述言語:日本語  

  136. 太陽風-磁気圏-電離圏結合過程の基礎理解としての磁気急始(SC)現象の姿

    第3回ジオスペース環境科学研究会   2008年3月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  137. SC-associated ionospheric electric fields at low latitude: FM-CW radar observation 査読有り

    Ikeda, A, K. Yumoto, M. Shinohara, K. Nozaki, A. Yoshikawa, A. Shinbori  

    Mem. Fac. Sci., Kyushu Univ., Ser. D, Earth and Planet. Sci.,XXXII, 1-632 巻 ( 1 ) 頁: 1-6   2008年2月

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    記述言語:英語  

  138. IMF南点に伴う磁気圏電場の応答とその空間依存性

    西村幸敏, 菊池崇, J. Wygant, 新堀淳樹, 辻裕司, 小野高幸, 飯島雅英, 熊本篤志  

    第4回磁気圏-電離圏複合系における対流に関する研究会抄録,50-68   2008年

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    記述言語:日本語  

  139. Transient flow shear in the duskside ionosphere observed by King Salmon HF radar

    堀智昭, 菊池崇, 辻裕司, 新堀淳樹, 大高一弘, 國武学, 亘慎一  

    第4回磁気圏-電離圏複合系における対流に関する研究会抄録、72-86   2008年

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    記述言語:英語  

  140. サブオーロラ帯から磁気赤道域における磁気急始(SC)に伴う磁場変動の日変化の特徴

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 亘慎一  

    第4回磁気圏―電離圏複合系における対流に関する研究会収録, 133-160   2008年

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    記述言語:日本語  

  141. 磁気嵐急始初期インパルスの数秒以内同時性と地面電離層導波管TM0モード伝播による理解

    菊池崇, 新堀淳樹, 辻裕司, 橋本久美子, 亘慎一, 荒木徹, M. A. Abdu  

    第4回磁気圏-電離圏複合系における対流に関する研究会抄録、161-168   2008年

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    記述言語:日本語  

  142. 磁気嵐時の極域磁気圏におけるプラズマ密度増加、イオン上昇流の観測

    北村成寿, 新堀淳樹, 西村幸敏, 小野高幸, 飯島雅英, 熊本篤志, 山田学, 渡部重十, 阿部琢美, A. W. Yau  

    第9回惑星圏研究会集録, 17–20   2008年

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    記述言語:日本語  

  143. 磁気嵐時の中緯度領域における地上磁場変動と電離圏電場との定量的関係

    辻裕司, 新堀淳樹, 西村幸敏, 菊池崇, 松岡彩子, 長妻努  

    第4回磁気圏-電離圏複合系における対流に関する研究会抄録、87-105   2008年

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    記述言語:日本語  

  144. Seasonal dependence of SC amplitude on magnetic local time 査読有り

    Shinbori, A, T. Kikuchi, T. Araki  

    American Geophysical Union Fall Meeting 2007   2007年12月

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    記述言語:英語  

  145. 地上-衛星観測から見た複合系としての磁気急始(SC)現象の姿-太陽風IMFの極性が与えるSCの振幅の日変化の変動の意味-

    新堀淳樹, 菊池崇, 荒木徹, 辻裕司, 工藤健一, 西村幸敏, 越石英樹, 松本晴久, 五家建夫  

    平成19年度名古屋大学太陽地球環境研究所研究集会「第3回磁気圏-電離圏複合系における対流に関する研究会」   2007年11月

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    記述言語:日本語  

  146. 磁気圏・プラズマ圏・地上における磁気急始(SC)の振幅分布と太陽風衝撃波によるオーロラの応答について

    新堀淳樹, 菊池崇, 辻裕司, 工藤健一, 荒木徹, 西村幸敏, 越石英樹, 松本晴久, 五家建夫  

    第3回地磁気の会   2007年11月

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    記述言語:日本語  

  147. 磁気急始(SC)の振幅の日変化を用いた電離圏-磁気圏結合の理解-SCの作るFACの季節変動からわかること

    新堀淳樹, 菊池崇, 荒木徹  

    平成19年度名古屋大学太陽地球環境研究所研究集会「第3回磁気圏-電離圏複合系における対流に関する研究会」   2007年11月

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    記述言語:日本語  

  148. Statistical view of large-scale electric field in the inner magnetosphere during geomagnetic storms

    Shinbori, A, Y. Nishimura, T. Ono, A. Kumamoto, T. Kikuchi, A. Matsuoka  

    International CAWSES Symposium   2007年10月

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    記述言語:英語  

  149. あけぼの衛星によってプラズマ圏磁気赤道付近で観測される静電的電子サイクロトロン高調波について

    新堀淳樹, 小野高幸, 大家寛  

    地球電磁気・地球惑星圏学会 第122回総会及び講演会   2007年9月

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    記述言語:日本語  

  150. SCの振幅の日変化に対する太陽風IMFと季節依存性

    新堀淳樹, 菊池崇, 荒木徹  

    地球電磁気・地球惑星圏学会 第122回総会及び講演会   2007年9月

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    記述言語:日本語  

  151. Generation mechanism of Z-mode waves in the equatorial plasmasphere 査読有り

    Y. Nishimura, T. Ono, M. Iizima, A. Shinbori, A. Kumamoto  

    Earth, Planets and Space59 巻 ( 9 ) 頁: 1027-1034   2007年9月

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    記述言語:英語  

    DOI: 10.1186/BF03352043

  152. 磁気急始(SC)の振幅の磁気地方時とその季節・太陽活動依存性

    新堀淳樹, 菊池崇, 荒木徹  

    平成19年度・第1回STE(太陽地球環境)現象報告会   2007年9月

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    記述言語:日本語  

  153. 磁気嵐における電離圏-磁気圏結合研究の時代背景と新展開

    新堀淳樹  

    地球電磁気・地球惑星圏関連夏の学校2007   2007年8月

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    記述言語:日本語  

  154. 磁気嵐時の内部磁気圏・極域電離圏電場の統計的描像

    新堀淳樹, 西村幸敏, 小野高幸, 熊本篤志, 菊池 崇  

    第31回極域宙空圏シンポジウム   2007年7月

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    記述言語:日本語  

  155. Electrostatic electron cyclotron harmonic waves observed by the Akebono satellite near the equatorial region of the plasmasphere 査読有り

    A. Shinbori, T. Ono, M. Iizima, A. Kumarnot, S. Shirai, A. Hanaoka, K. Okamoto, M. Ohashi, H. Oya  

    EARTH PLANETS AND SPACE59 巻 ( 6 ) 頁: 613-629   2007年6月

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    記述言語:英語  

    Analysis of the plasma wave observation data provided by the plasma waves and sounder experiment (PWS) on board the Akebono satellite frequently reveals the presence of electrostatic electron cyclotron harmonic (ESCH) waves in the low-latitude region (MLAT &lt; 45 degrees) of the plasmasphere within an altitude range from about 3000 km to the apogee of the satellite (initial apogee was 10,500 km). Even at moderate or low geomagnetic activity, intense ESCH waves often appear near the equatorial region of the plasmasphere above the upper hybrid resonance (UHR) frequency at the lowest harmonic number branch of the f(Qn) ESCH waves. We identified these plasma waves as the equatorial plasmasphere f(Qn) waves (EP-f(Qn)). The spectra of the EP-f(Qn) waves are characterized by a narrow band structure and by a strong nature, with a wave intensity that ranges from 3.46 x 10(-8) to 3.31 X 10(-4) V/m. The maximum intensity is nearly coincident with the upper limit of the PWS receiver in the low-gain mode. Statistical analysis results reveal that the EP-f(Qn) waves are observable in all the local time sectors; however, the occurrence probability shows a clear enhancement in the early morning sector of 01-03 MLT in the plasmasphere. The EP-f(Qn) wave activities are suppressed within a period of strong magnetic disturbances as well as solar minimum phase. The linear dispersion relation analysis using a two-component plasma model reveals that supra-thermal plasma with the energy of about 750 eV and with a large temperature anisotropy (A = T-perp/T-parallel - 1 &gt; 40) must be present in order to realize an appearance of a positive growth rate at the observed frequency and propagation angle of the ESCH waves. Since the hot plasma with such a high anisotropy has not been detected, the validity of the present two-component plasma model remains an open question. The occurrence feature of the ESCH waves showed that there is a constant activation or a constant flow-in of free energy to generate the strong plasma instability of ESCH waves near the post-midnight sector of the plasmasphere. The existence of ESCH waves revealed that the nature of the plasmaspheric plasma is more turbulent and active than has been believed.

    DOI: 10.1186/BF03352723

    Web of Science

  156. Evolution of ring current and radiation belt particles under the influence of storm-time electric fields 査読有り

    Y. Nishimura, A. Shinbori, T. Ono, M. Iizima, A. Kumamoto  

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS112 巻 ( A6 )   2007年6月

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    記述言語:英語  

    Electric field and potential distributions in the inner magnetosphere during geomagnetic storms have been investigated using the Akebono/EFD data. Using this electric field, we study injection of ring current particles and acceleration of radiation belt electrons by single-particle calculations. During the main phase, the dawn-dusk electric field is intensified especially in a range of 2 &lt; L &lt; 5 with a maximum amplitude of 6 mV/m on the duskside, and a two-cell convection pattern with a potential difference of 180 kV is identified. The convection pattern on the equatorial plane is significantly distorted with a large potential drop of 70 kV on the dawn and dusk sectors, indicating an intrinsic source of large-scale electric field in the inner magnetosphere. The plasma sheet ions are gathered into the dusk to premidnight sector in the inner magnetosphere in the region of enhanced electric field due to the strong E x B drift. The ions are transported into around 4 R-E with an acceleration of more than 1 order of magnitude within 40 min, conserving the first adiabatic invariants. Relativistic electrons with initial energy of some hundreds of kiloelectron volts at 5 R-E are energized to more than 100 keV for 3 hours. The energy spectrum during the recovery phase of 9 October 1990 geomagnetic storm observed by the CRRES satellite is reproduced without the radial diffusion or nonadiabatic acceleration by plasma waves. It is possible that this acceleration process is the inhomogeneity of the large-scale electric field, which corresponds to the del x E term along orbits of electrons around the Earth.

    DOI: 10.1029/2006JA012177

    Web of Science

  157. 磁気急始(SC) の振幅の磁気地方時と太陽風IMF の依存性-3

    新堀淳樹, 菊池崇, 荒木徹  

    日本惑星科学連合2007年大会   2007年5月

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    記述言語:日本語  

  158. 磁気嵐時における内部磁気圏電場について

    新堀淳樹, 西村幸敏, 小野高幸, 熊本篤志, 菊池崇  

    日本地球惑星科学連合2007年大会, 招待講演   2007年5月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  159. 地上-衛星で見た2006年12月14日の磁気嵐における磁場変動

    新堀淳樹, 辻裕司  

    平成18年度・第2回STE(太陽地球環境)現象報告会   2007年3月

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    記述言語:日本語  

  160. 磁気嵐と内部磁気圏電場

    新堀淳樹  

    第10回学術創成分担者会議・年度末報告会   2007年3月

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    記述言語:日本語  

  161. あけぼの衛星観測による磁気嵐時の極域・中低緯度電離圏電場について

    新堀淳樹, 西村幸敏, 小野高幸, 熊本篤志, 菊池崇  

    平成18年度名古屋大学太陽地球環境研究所研究集会 「中緯度短波レーダー研究会」   2007年2月

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    記述言語:日本語  

  162. 磁気嵐の発達・衰退過程におけるサブオーロラ帯・極域電離圏内の電場分布の変化について

    新堀淳樹, 西村幸敏, 菊池崇, 小野高幸, 熊本篤志  

    宇宙プラズマ/太陽系環境研究の将来構想座談会5 (SSF5) ~地球磁気圏地上-衛星観測共同研究の深化に向けて~   2007年1月

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    記述言語:日本語  

  163. 複合系物理の基礎課程の理解としての地上-衛生観測から見た磁気急始(SC)現象の姿

    新堀淳樹, 菊池崇, 辻裕司, 工藤健一, 荒木徹, 西村幸敏, 越石英樹, 松本晴久, 五家建夫  

    第3回磁気圏―電離圏複合系における対流に関する研究会収録, 85-141   2007年

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    記述言語:日本語  

  164. 磁気嵐における電離圏電場の時間・空間発展

    辻裕司, 新堀淳樹, 菊池崇  

    第3回磁気圏―電離圏複合系における対流に関する研究会収録、150-177   2007年

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    記述言語:日本語  

  165. Variations of the electric field distribution in the sub-auroral latitude and polar ionosphere during geomagnetic storms 査読有り

    Shinbori, A, Y. Nishimura, T. Ono, A. Kumamoto, T. Kikuchi  

    American Geophysical Union Fall Meeting 2006   2006年12月

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    記述言語:英語  

  166. 新堀淳樹, 西村幸敏, 菊池崇, 小野高幸, 荒木徹

    新堀淳樹, 西村幸敏, 菊池崇, 小野高幸, 荒木徹  

    平成18年度名古屋大学太陽地球環境研究所研究集会 「第2回 磁気圏-電離圏複合系における対流に関する研究会」   2006年11月

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    記述言語:日本語  

  167. 磁気急始(SC)の振幅の磁気地方時と太陽風IMFの依存性-2

    新堀淳樹, 西村幸敏, 菊池崇, 小野高幸, 荒木徹  

    地球電磁気・地球惑星圏学会 第120回総会・講演会   2006年11月

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    記述言語:日本語  

  168. Storm-time electric field distribution in the inner magnetosphere 査読有り

    Y. Nishimura, A. Shinbori, T. Ono, M. Iizima, A. Kumamoto  

    GEOPHYSICAL RESEARCH LETTERS33 巻 ( 22 )   2006年11月

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    記述言語:英語  

    The distribution of the storm-time electric field in the inner magnetosphere has been investigated by using the Akebono/EFD data within a period from 1989 to 1995. During the main phase of geomagnetic storms, the strong electric field appears between L = 2 and L = 6 in both dawn and dusk sectors with the magnitude from 2 to 4 mV/m, and the maximum value appears at L = 3 in the dusk sector. During the recovery and weakly disturbed period, the region with intense electric field moves outward with decreasing the amplitude. This structure of the localized electric field is quite different from the Volland-Stern electric field model, suggesting the existence of another electric field source other than the large-scale convection electric field. During quiet periods, although the electric field fairly follows the corotation electric field, the distribution at L = 3.5 indicates a small deviation from pure corotation.

    DOI: 10.1029/2006GL027510

    Web of Science

  169. 磁気嵐時の内部磁気圏電場について

    新堀淳樹, 菊池崇, 西村幸敏, 小野高幸  

    第2回ジオスペース環境科学研究会   2006年9月

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    記述言語:日本語  

  170. 磁気嵐時におけるプラズマ圏並びに極域電離圏内の電場分布とその変化

    新堀淳樹, 西村幸敏, 小野高幸, 飯島雅英, 熊本篤志, 菊池 崇  

    第30回極域宙空圏シンポジウム   2006年8月

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    記述言語:日本語  

  171. Electric Field and Plasma Dynamics in the Inner Magnetosphere and Plasmasphere during a Geomagnetic Storm 査読有り

    Shinbori, A, Y. Nishimura, T. Ono, M. Iizima, A. Kumamoto  

    COSPAR   2006年7月

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    記述言語:英語  

  172. 内部磁気圏電場の統計的描像-2

    新堀淳樹, 西村幸敏, 小野高幸, 飯島雅英, 熊本篤志  

    日本地球惑星科学連合2006年大会, 招待講演   2006年5月

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    記述言語:日本語   掲載種別:研究発表ペーパー・要旨(全国大会,その他学術会議)  

  173. 磁気急始(SC)の磁場変動の振幅に関する未解決問題点

    新堀淳樹, 西村幸敏, 小野高幸, 飯島雅英, 熊本篤志  

    第1回地磁気の会   2006年3月

     詳細を見る

    記述言語:日本語  

  174. Statistical studies of fast and slow Z-mode plasma waves in and beyond the equatorial plasmasphere based on long-term Akebono observations 査読有り

    Y. Nishimura, T. Ono, M. Iizima, A. Shinbori, A. Kumamoto, H. Oya  

    Earth, Planets and Space58 巻 ( 3 ) 頁: 343-346   2006年3月

     詳細を見る

    記述言語:英語  

    DOI: 10.1186/BF03351930

  175. Enhancements of magnetospheric convection electric field in the inner magnetosphere associated with sudden commencements 査読有り

    Shinbori, A, T. Ono, M. Iizima, A. Kumamoto  

    Advances in Space Research, Volume 38, Issue 8, 1595-1607, doi: 10.1016/j.asr.2005.05.082   2006年1月

     詳細を見る

    記述言語:英語  

    DOI: 10.1016/j.asr.2005.05.082

  176. 磁気急始(SC)の振幅の磁気地方時と太陽風IMF依存性

    新堀淳樹, 西村幸敏, 小野高幸, 菊池崇, 荒木徹  

    第2回磁気圏―電離圏複合系における対流に関する研究会収録, 35-74   2006年

     詳細を見る

    記述言語:日本語  

  177. 磁気嵐時の内部磁気圏電場と沿磁力線電流

    西村幸敏, 新堀淳樹, 小野高幸, 飯島雅英, 熊本篤志  

    第2回磁気圏―電離圏複合系における対流に関する研究会収録、75-84   2006年

     詳細を見る

    記述言語:日本語  

  178. あけぼの衛星で見る磁気急始(SC)並びに磁気嵐に伴う内部磁気圏電場構造の時空間変動

    新堀淳樹, 西村幸敏, 小野高幸, 飯島雅英, 熊本篤志, 大家寛  

    平成18年度名古屋大学太陽地球環境研究所研究集会「第1回磁気圏-電離圏複合系における対流に関する研究会」   2005年11月

     詳細を見る

    記述言語:日本語  

  179. 内部磁気圏電場の統計的描像

    新堀 淳樹, 西村 幸敏, 小野 高幸, 飯島 雅英, 熊本 篤志  

    地球電磁気・地球惑星圏学会 第118回総会・講演会   2005年10月

     詳細を見る

    記述言語:日本語  

  180. 磁気嵐時におけるオーロラキロメートル放射(AKR)と地球ヘクトメートル放射(THR)の活動について

    新堀 淳樹, 西村 幸敏, 小野 高幸, 飯島 雅英, 熊本 篤志, 佐藤 由佳  

    地球電磁気・地球惑星圏学会 第118回総会・講演会   2005年9月

     詳細を見る

    記述言語:日本語  

  181. 磁気嵐中に観測される内部磁気圏・プラズマ圏内の電場変動について

    新堀 淳樹, 小野 高幸, 飯島 雅英, 熊本 篤志, 大家 寛  

    地球惑星圏関連学会2005年合同大会   2005年5月

     詳細を見る

    記述言語:日本語  

  182. 磁気急始(SC)の振幅の磁気地方時と太陽風IMFの依存性

    新堀 淳樹, 小野 高幸, 飯島 雅英, 熊本 篤志, 西村 幸敏  

    地球惑星圏関連学会2005年合同大会   2005年5月

     詳細を見る

    記述言語:日本語  

  183. Convection electric fields in the inner magnetosphere caused by sudden commencements

    Shinbori, A, T. Ono, M. Iizima, A. Kumamoto  

    Joint International Workshop on Space Weather: On the causes of southward IMF and space weather, science and application for Japanese CAWSES, Tokyo   2005年4月

     詳細を見る

    記述言語:英語  

  184. Electrodynamics in the duskside inner magnetosphere and plasmasphere during a super magnetic storm on March 13-15, 1989 査読有り

    A Shinbori, Y Nishimura, T Ono, M Iizima, A Kumamoto, H Oya  

    EARTH PLANETS AND SPACE57 巻 ( 7 ) 頁: 643-659   2005年

     詳細を見る

    記述言語:英語  

    Variations of cold plasma density distribution and large-scale electric field in the inner magnetosphere and plasmasphere during a geomagnetic storm were investigated by using the observation data of the Akebono satellite which has been carried out for more than 15 yeas since March, 1989. We focus on the super geomagnetic storm on March 13-15, 1989, for which the maximum negative excursion of the Dst index was -589 nT. During the main phase of the magnetic storm, the strong convection electric field with a spatially inhomogeneous structure appears in the inner magnetosphere between L = 2.0 and 7.0. The averaged intensity of the electric field was in a range of about 2.5-9.2 mV/m. The spatial distribution in the magnetic equatorial region indicates that the magnitude within an L-value range of 2.2-7.0 is much larger than that observed at L = 7.0-10.0. Associated with the appearance of the strong convection electric field, the cold plasma density near the trough region around L = 3.0-6.0 was enhanced with one or two order magnitude, compared with that in the magnetically quiet condition. This implies that a mount of the ionospheric plasma may be supplied from the topside ionosphere into the trough and plasmasphere regions by the frictional heating due to the fast plasma convection in the ionosphere as pointed out by previous studies on the enhancements of plasma density in these regions, based on incoherent scatter radar and total electron content (TEC) observations (e.g., Yeh and Foster, 1990; Foster et al., 2004). During the recovery phase of the magnetic storm, the convection electric field observed in the inner magnetosphere and plasmasphere regions recovers within 3-4 days almost up to the level of the magnetically quiet condition.

    DOI: 10.1186/BF03351843

    Web of Science

  185. あけぼの衛星で見る磁気急始(SC)・磁気嵐に伴う内部磁気圏電場構造の時空間変動とプラズマ圏ダイナミクス

    新堀淳樹, 小野高幸, 飯島雅英, 熊本篤志, 大家寛  

    第1回磁気圏―電離圏複合系における対流に関する研究会収録, 58-84   2005年

     詳細を見る

    記述言語:日本語  

  186. 地磁気擾乱時における放射線帯電子のピッチ角分布の変動

    西村 幸敏, 新堀 淳樹, 小野 高幸, 飯島 雅英, 熊本 篤志, 森岡 昭  

    第5回惑星電磁圏・大気圏研究会集録   2005年

     詳細を見る

    記述言語:日本語  

  187. プラズマ圏磁気赤道域UHR、Z-mode波動の統計的描像

    西村幸敏, 小野高幸, 飯島雅英, 熊本篤志, 新堀淳樹, 大家寛  

    第9回SGEPSS生存圏波動分科会研究収録、WAVE09-02   2005年

     詳細を見る

    記述言語:日本語  

  188. 磁気嵐時の背景電場による放射線、環電流粒子生成

    西村幸敏, 新堀淳樹, 小野高幸, 飯島雅英, 熊本篤志  

    第1回磁気圏―電離圏複合系における対流に関する研究会収録, 29-34   2005年

     詳細を見る

    記述言語:日本語  

  189. SC・磁気嵐中における内部磁気圏・プラズマ圏の電場応答とプラズマ密度変動

    新堀 淳樹, 小野 高幸  

    平成16年度 名古屋大学太陽地球環境研究所研究集会 「中緯度短波レーダー研究会」   2004年10月

     詳細を見る

    記述言語:日本語  

  190. 磁気嵐中に内部磁気圏・プラズマ圏で観測される電場について

    新堀 淳樹, 小野 高幸, 飯島 雅英, 熊本 篤志, 大家 寛  

    プラズマ圏・内部磁気圏研究集会   2004年8月

     詳細を見る

    記述言語:日本語  

  191. SC related electric and magnetic field phenomena observed by the Akebono satellite inside the plasmasphere 査読有り

    Shinbori, A, T. Ono, M. Iizima, A. Kumamoto, H. Oya  

    COSPAR56 巻 ( 2 ) 頁: 269-282   2004年7月

     詳細を見る

    記述言語:英語  

    Electric and magnetic field variations inside the plasmasphere associated with SCs identified on the ground are analyzed based on the Akebono satellite observations which have been carried out more than 13 years since March 1989. 126 electric field observation data corresponding to SCs show abrupt change of intensity as well as direction within a few minutes inside the plasmasphere. Temporal variations of the electric field showed a bipolar waveform with the amplitude range of 0.2-38 mV/m. The electric field signature is followed by a dumping oscillation with the period of Pc3-4 ranges. The magnetic field variations of 33 SCs also show an abrupt increase of 0.2-65 nT within a few minutes, which indicate the compression of the magnetosphere due to the discontinuity of solar wind. The initial excursion of the electric field during SCs tends to be directed westward. The amplitude does not show a dependence on magnetic local time that has been observed outside the plasmasphere. The magnitude of the electric field variations tends to be proportional with the power of 0.6 to the magnetic field variation in the plasmasphere. The Poynting vector of the initial SC impulse is directed toward the earth, which suggests that energy of magnetic disturbances associated with SCs propagates toward the earth inside the plasmasphere with the refraction due to the plasma density gradient. One of the most interesting results from the present study is that a DC offset of the Ey component of the electric field appears after the initial electric field impulse associated with SCs. This signature is interpreted to be a magnetospheric convection electric field penetration into the inner plasmasphere (L=2.5). The intensity of the offset of the Ey field gradually increases by 0.5-2.0 mV/m about 1-2 minutes after the onset of the initial electric field impulse and persists about 10-30 minutes.

    DOI: 10.1186/BF03353409

    Web of Science

  192. SC related plasma waves observed by the Akebono satellite in the polar region and inside the plasmasphere region

    Shinbori, A, T. Ono, M. Iizima, A. Kumamoto, H. Oya  

    International Review Meeting on the Northern Environmental Change Research Project108 巻 ( A12 )   2004年3月

     詳細を見る

    記述言語:英語  

    Plasma wave phenomena associated with sudden commencements (SC) are analyzed using the database of the Akebono satellite observations that have been carried out for more than 13 years since March 1989. All the 719 data sets simultaneously observed in the periods of SC events show that plasma waves are enhanced with one-to-one correspondence to SCs in entire regions of the polar cap, auroral zone, and plasmasphere within a response time of +/-90 s. In the middle latitude and equatorial regions of the plasmasphere, intensification and frequency shift of electromagnetic whistler mode, LHR waves, and ion cyclotron harmonic waves are found. The electric field variations in this region also show clear response to the onset of SCs with the amplitude of 0.2-30 mV/m. The variations are observed in the nightside as well as dayside sectors, and no clear dependence of magnetic latitude, local time, and L shell is found. On the other hand, electrostatic whistler mode waves and electromagnetic ion cyclotron waves which show broadband spectra are generated in the high-latitude region. Spectra of low-energy particles observed simultaneously with the enhancement of these plasma waves show that electron fluxes are enhanced in all of pitch angle bins of the low-energy particle detector onboard the Akebono satellite. Near the cusp region, the ion fluxes are more enhanced in the upward direction than in the downward direction along the magnetic field lines. In about half of the cases of the high-latitude events, sudden appearance and intensification of AKR are also found after the onsets of SC. The delay time between the onsets of SC and AKR enhancement shows several minutes with the average time of 5.7 min. Time differences between the onsets of SC measured at Kakioka Magnetic Observatory and plasma wave enhancements observed by the Akebono satellite show positive correlation with possible delay time according to the propagation route of SC disturbances. Propagation character of SC disturbances shows two group signatures: one group takes a route which crosses the geomagnetic equator region with an average speed of 389.5 km/s. The speed is almost consistent with plasmaspheric fast-mode MHD wave velocity. The other group takes a route which starts from the dayside cusp region. In the second case, the SC disturbances propagate through the polar ionosphere region from the dayside to the nightside sectors with an average speed of 47 km/ s in the X-GSM coordinate corresponding to the ionospheric fast-mode MHD wave velocity.

    DOI: 10.1029/2003JA009964

    Web of Science

  193. あけぼの衛星によって観測されるプラズマ圏磁気赤道域付近の静電的電子サイクロトロン高調波の出現特性について

    新堀淳樹, 小野高幸, 飯島雅英, 熊本篤志, 大家寛  

    第8回SGEPSS波動分科会研究会収録, WAVE08-02   2004年

     詳細を見る

    記述言語:日本語  

  194. SC・磁気嵐中に内部磁気圏・プラズマ圏内で観測される電場変動について

    新堀淳樹, 小野高幸, 飯島雅英, 熊本篤志, 大家寛  

    第4回CAWSES電磁圏シンポジウム研究会収録、9-12   2004年

     詳細を見る

    記述言語:日本語  

  195. プラズマ圏磁気赤道域Z-mode波の放射機構 - keV電子による直接励起の可能性

    西村幸敏, 小野高幸, 飯島雅英, 新堀淳樹, 熊本篤志, 大家寛  

    第4回惑星電磁圏・大気圏研究会集録,103-107   2004年

     詳細を見る

    記述言語:日本語  

  196. SCに伴うプラズマ圏内のプラズマ波動、場の変動特性について

    新堀 淳樹, 小野 高幸, 飯島 雅英, 熊本 篤志, 大家 寛  

    地球電磁気・地球惑星圏学会 第114回総会・講演会   2003年11月

     詳細を見る

    記述言語:日本語  

  197. SC-related kilometric and hectometric radiations observed by the Akebono satellite in the polar regions 査読有り

    Shinbori, A, T. Ono, M. Izima, K. Kumamoto, H. Oya  

    Advances in polar upper atmosphere research17 巻   頁: 60-76   2003年9月

     詳細を見る

    記述言語:英語  

  198. 磁気急始(SC)に伴うプラズマ波動、場の変動現象について

    新堀 淳樹, 小野 高幸  

    プラズマ圏・内部磁気圏研究集会   2003年8月

     詳細を見る

    記述言語:日本語  

  199. SC triggered plasma wave and field phenomena observed by the Akebono satellite in the plasmasphere

    Shinbori, A, T. Ono, M. Iizima, A. Kumamoto, H. Oya  

    International Union of Geodesy and Geophysics   2003年7月

     詳細を見る

    記述言語:英語  

  200. SC triggered plasma wave and field phenomena observed by the Akebono satellite in the plasmasphere

    Shinbori, A, T. Ono, M. Iizima, A. Kumamoto, H. Oya  

    International Union of Geodesy and Geophysics   2003年7月

     詳細を見る

    記述言語:英語  

  201. SC・磁気嵐に伴うプラズマ圏内のプラズマ波動、場の変動現象について

    新堀 淳樹, 小野 高幸  

    内部磁気圏分科会   2003年5月

     詳細を見る

    記述言語:日本語  

  202. SC-triggered plasma waves observed by the Akebono satellite in the polar regions and the plasmasphere 査読有り

    Shinbori, A, T. Ono, H. Oya  

    Advances in polar upper atmosphere research16 巻   頁: 126-135   2002年9月

     詳細を見る

    記述言語:英語  

  203. SCに伴うプラズマ圏内の諸現象と擾乱の伝播

    新堀 淳樹, 小野 高幸, 大家 寛  

    プラズマ圏・内部磁気圏研究会   2002年8月

     詳細を見る

    記述言語:日本語  

  204. SCに伴うAKRの発生について

    新堀 淳樹, 小野 高幸, 大家 寛  

    第26回極域における電離圏磁気圏総合観測シンポジウム   2002年7月

     詳細を見る

    記述言語:日本語  

  205. SC triggered disturbances in the magnetosphere and plasmasphere

    Shinbori, A, T. Ono, H. Oya  

    Western Pacific Geophysics Meeting 2002   2002年7月

     詳細を見る

    記述言語:英語  

  206. SCに伴う磁気圏内擾乱域の発生と伝播について

    新堀 淳樹, 小野 高幸, 大家 寛  

    地球惑星圏関連学会2002年合同大会   2002年5月

     詳細を見る

    記述言語:日本語  

▼全件表示

科研費 9

  1. 中緯度大型短波レーダーを活用した高時間分解能ジオスペース観測網の構築

    研究課題/研究課題番号:22H01284  2022年4月 - 2027年3月

    科学研究費助成事業  基盤研究(B)

    西谷 望, 堀 智昭, 新堀 淳樹, 小路 真史, 寺本 万里子

      詳細を見る

    担当区分:研究分担者 

    全世界的電離圏観測網である、中緯度SuperDARNの1基である北海道-陸別第一HFレーダーにイメージング受信機を実装し、高時間・空間分解能化をはかる。上記の高性能化を実現して得られるデータを活用し、また他の観測データを併用することにより地球近傍磁気圏・電離圏(ジオスペース)の短周期擾乱生成のメカニズムの解明に取り組み、擾乱現象の生成・発達・伝搬・消滅メカニズムを明らかにする。さらには、これらの変動現象の探求・解明を通じて、ジオスペース内の磁気圏・電離圏・熱圏の領域間相互作用の重要性を、実際のSuperDARN・観測データにより実証する。さらには宇宙天気研究・予報への応用の糸口をつける。

  2. 共通環境における中緯度大型短波レーダー網による広域電磁気圏環境変動過程の解明

    研究課題/研究課題番号:18KK0099  2018年10月 - 2024年3月

    科学研究費助成事業  国際共同研究加速基金(国際共同研究強化(B))

    西谷 望, 堀 智昭, 新堀 淳樹, 高橋 直子

      詳細を見る

    担当区分:研究分担者 

    日米双方の中緯度SuperDARNレーダー装置・観測データを活用し、レーダー運用及びデータ解析環境の共通化を図った上で、地球自転軸と地磁気双極子軸のずれに起因する双方のレーダー観測域の地理的相違性に注目して、以下の課題に取り組む。1) SAPSやSEDに代表される電子密度・電場変動現象の空間・時間分布および地理・地磁気軸オフセット効果の影響。2)太陽風中擾乱やサブストーム現象が地球の磁気圏電離圏電場の空間・時間変動に与える影響。3)各種磁気流体波動の特性および地理・地磁気軸オフセット効果の影響。特に1分程度の短時間で劇的に変動する現象の特性およびその発生過程を明らかにすることが本研究課題の
    主要な目的である。
    当該年度は大学院生を含む日本側研究者数名をアメリカ側代表研究機関に派遣し、またSuperDARN国際会議を始めとする複数の国際会議に派遣するする予定であったが、コロナ禍の影響によりオンラインによる研究交流・成果発表を代わりに実施した。特に、2021年3月にオンラインで開催されたPWING国際会議・スクールにおいては、SuperDARNレーダーを用いた研究成果についての招待講演を実施した。
    また、北海道陸別町に設置したSuperDARN北海道-陸別第一・第二レーダーの運用を継続して実施するとともに、SuperDARNレーダー次世代受信機の開発を進め、2020年6-7月に試験運用を実施して本運用のための見通しを立てた()。さらには名古屋大に設置した遠隔受信機の初期運用結果に関する論文が受理され、2021年4月に出版された。その他、日米の共同研究者を共著とする論文が出版された。
    令和2年度は直接相手側機関を訪問しての共同研究を実施したり、国際会議において同時に参加したアメリカ側の研究者と今後の共同研究計画の進め方について議論を行うことができなかったが、オンライン会議や電子メールを活用することにより、共同研究を推進することができた。実際に成果論文が出版され、オンライン国際・国内会議における発表が多くなされた。
    日本国内ではSuperDARN北海道-陸別第一・第二レーダーの運用を継続してデータを蓄積し、本格的な共同研究に備えるとともに、SuperDARNレーダー次世代受信機の開発を進め、本格的な試験運用を2020年6-7月に現地において実施し、本運用のための準備態勢を整えることができた。残念ながら本運用のための機器購入を目指して申請した科研費は不採択になったが、今後科研費を始めとする複数の機会を追求するつもりである。
    2020年2月末頃からCOVID-19ウィルスの影響により、すべての国際会議・国内会議の(オンラインを除く)開催がストップされているが。令和3年度中に問題が解決し、従来の状況に戻ることが強く期待される。
    可能な手段を活用して日米間の共同研究を進める。前項で記述したように、日本側の研究者の共同研究機関のバージニア工科大学への派遣や、国内外で行われる国際会議への参加(子それ以前に国際会議自身の開催)が現時点で極めて不透明な状況になっているが、電子メールやオンライン会議等を通じて共通環境の整備を推進するとともに、その基盤の上で共同研究をさらに進める。世界的にみるとワクチン接種が進んでいるところでは状況が大幅に改善しているところもあるので、国際間の往来に見通しが立ったところで、国内外で開催される国際会議等を活用するとともに、日本側研究者のアメリカ共同研究機関への訪問を検討する。このように考えられる手段を活用して共通のレーダー運用・データ解析環境をより一層整備した上で、共同研究を進めていく。
    並行して、日本国内でのSuperDARN観測を継続するとともに、SuperDARNレーダー次世代受信機の開発を進め、本運用のための予算獲得を目指す。アメリカ側の同様の機器の開発・運用状況について先方と密に連絡を取り合うことで効率的な情報交換を行っていく。

  3. 地磁気擾乱時における電離圏電場分布の変動と電離圏擾乱ダイナモとの関係

    2014年4月 - 現在

    科学研究費補助金  基盤研究(C)

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    担当区分:研究代表者 

  4. 地磁気擾乱時における電離圏電場分布の変動と電離圏擾乱ダイナモとの関係

    研究課題/研究課題番号:26400478  2014年4月 - 2019年3月

    新堀 淳樹

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    担当区分:研究代表者 

    配分額:4810000円 ( 直接経費:3700000円 、 間接経費:1110000円 )

    太陽表面現象(太陽フレアなど)や太陽風構造の急変に伴う太陽風擾乱が引き起こす磁気嵐は、磁気圏から電離圏に至る広範な領域の電磁場やプラズマ環境を激変させる。本研究では、磁気嵐に伴うグローバルな電離圏変動の原因となる電離圏電場の空間分布と電子密度の時間・空間変動を明らかにするために、太陽風、地磁気、および全電子数(TEC)データの解析を行った。その結果、磁気嵐主相時には、極域電離圏では2セル型の対流が発達し、極域電場が磁気赤道に侵入を示唆する赤道ジェット電流の増大が見られた。それに伴って午後側の中緯度電離圏の電子密度が増加し、磁気嵐の発達とともにぞの増加領域が低緯度側へ伝搬することがわかった。
    磁気嵐に伴って午後側の中緯度電離圏で電子密度が増加し始め、それが低緯度へ拡大していく様相を示した本研究の結果は、これまでこの電子密度増加の起源が赤道電離圏にあると考えられていた過去の研究の概念では説明することはできず、磁気嵐に伴う中緯度電離圏変動について新しい知見を与えるものである。また、この中緯度に形成される電離圏電子密度増加域は非常に狭い構造を持ち、その境界付近で電子密度が急激に変化する。このような変化は衛星測位誤差を大きくさせる要因であり、本研究で得られた成果は、そのような電離圏電子密度擾乱の発生予測と予報への応用研究につながるという社会的意義を持つ。

  5. 磁気嵐時におけるグローバル地磁気変動と電離圏擾乱ダイナモに関する研究

    2011年4月 - 2014年3月

    科学研究費補助金  若手研究(B)

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    担当区分:研究代表者 

  6. 磁気嵐時におけるグローバル地磁気変動と電離圏擾乱ダイナモに関する研究

    研究課題/研究課題番号:23740369  2011年 - 2014年

    新堀 淳樹

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    担当区分:研究代表者 

    配分額:4030000円 ( 直接経費:3100000円 、 間接経費:930000円 )

    本研究では、磁気嵐の発達、および衰退過程における地磁気の全球的な変動特性と下部熱圏風の変動がもたらす地磁気変動を明らかにするために、高緯度から赤道域の観測点から得られた地磁気と太陽風データを組み合わせた解析を行った。その結果、惑星間磁場の南転によって発生する磁気嵐主相時には領域1型のグローバルな電流系が発達し、その電流系に関連した電場が磁気赤道域に侵入することによって、昼間側磁気赤道で東向きジェット電流を強めていた。一方、惑星間磁場の北転に伴って磁気嵐回復相に入ると、中緯度において領域2型の電流系が卓越し、その電流系がつくる遮蔽電場が昼間側磁気赤道の西向きジェット電流を駆動していた。

  7. 中間圏・下部熱圏における大気波動のレーダーネットワーク観測

    研究課題/研究課題番号:22253006  2010年4月 - 2016年3月

    津田 敏隆

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    担当区分:研究分担者 

    高度60-150 kmの中間圏・下部熱圏(MLT)領域における大気波動の活動および平均風の長期・短期変動に着目し、大気圏上下結合過程を研究した。アジア・太平洋の赤道域に設置された流星・中波帯(MF)レーダーによる長期間連続観測で蓄積された観測データベース(IUGONET)を活用した。MLT領域での大気重力波活動の季節変化が熱帯対流圏の積雲対流と相関していることを示した。平均風が半年・1年・準2年・季節内周期で振動する特性を解析し、これらの周期的・不規則変動の生成には大気重力波と平均流の相互作用による効果が重要であることを示した。また平均南北風が10年スケールの長期トレンドを持つことが分かった。

  8. 磁気嵐に伴う磁気圏・電離圏内におけるプラズマ擾乱の発生と発達過程の研究

    2006年4月 - 2009年3月

    科学研究費補助金 

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    担当区分:研究代表者 

    太陽フレア現象によって放出される高密度・高温プラズマ雲が地球磁気圏に衝突することによって発生する磁気急始(SC)現象は、開始時刻やその発生要因が見極めやすい変動形態を持つため、太陽風-磁気圏-電離圏相互作用という磁気圏物理の基礎課程を理解する上で非常に重要な擾乱現象である。本年度は、磁気赤道から中緯度領域におけるSCの磁場振幅の磁気緯度と磁気地方時の分布を明らかするために、ヤップ、グアム、沖縄、柿岡、女満別そしてパラツンカの6つの地磁気観測点から得られた長期の地磁気データを用いてSCのMain Impulse(MI)期の磁場振幅の統計解析を行った。その結果、昼間側の中緯度における磁場変動は、圧縮時によって生成される領域1型の沿磁力線電流(FAC)のもたらすtwo-cell型の電離圏Hall電流の作る磁場変化を示し、その影響が少なくとも沖縄付近の低緯度まで広がっていた。一方、低緯度では、磁場振幅が正午付近で最大となる磁気圏界面電流のつくる磁場変動が卓越することを示したが、本研究の精密な解析により、極域起源の電離圏電流の作る磁場変動が約7%含まれることを新たに見出した。さらに、磁気赤道の8時から16時の昼間側において、Cowling効果による顕著なSCの磁場振幅の増大が見受けられ、低緯度の2-3倍に達していた。その最大値を与える磁気地方時は11時付近であった。そして、もう一つの興味深い結果は、磁気赤道から中緯度の全ての領域で真夜中付近を最大とする2次的なSCの磁場振幅の増大が見られたことである。その真夜中付近の振幅は。顕著な磁気緯度の依存性を持っており、磁気緯度の増加とともに振幅が増加するという傾向を示した。このことから、この磁場変動をもたらす原因は、MI期に形成されるFACの作る磁場変化であり、その影響が中緯度や低緯度だけでなく、磁気赤道にまで及んでいることをはじめて示した。

  9. 磁気急始(SC)による磁気圏内プラズマ擾乱の発達過程の研究

    2004年4月 - 2006年3月

    科学研究費補助金 

      詳細を見る

    担当区分:研究代表者 


    磁気急始(SC)やそれに続く磁気嵐に伴って引き起こされる内部磁気圏・プラズマ圏内の電流、電場や磁気擾乱の発生並びに発達過程でのプラズマの応答、擾乱の伝播、エネルギーや物質の輸送機構ついては、現在、未発達の分野として残されている。本研究では、内部磁気圏・プラズマ圏におけるSC、その後の磁気嵐の発達過程に呼応した擾乱の発生、エネルギーの伝達や物質の輸送機構について解明することを目的としている。本年度は1989年3月から2003年12月に至るまでの約15年間という長期間のあけぼの衛星の電場並びにプラズマ波動観測データを用いて、磁気嵐における内部磁気圏電場の形成過程とプラズマダイナミクスの解明に向けた解析を行った。その結果、各磁気嵐の主相時においてこれまで存在していなかった空間的に不均質な大電場がL=2.0-7.0の地球近傍の朝側領域と夕方側の内部磁気圏内に形成されていることが判明し、その最大強度は、数10mV/mにまで達していた。また、この電場の最大強度は、磁気嵐の規模に呼応して強くなる傾向を示し、その最大強度をとる位置も地球側へ接近してくるという様相が明らかとなった。特に、この不均質な大電場が主に動径方向を向いているという特徴に本研究では着目し、夜側のプラズマシートから内部磁気圏に注入された環電流粒子の局所的な電荷分離によって形成されるという新たな内部磁気圏電場モデルを提案した。一方、プラズマ圏のプラズマ密度構造と磁気嵐時の電場構造との比較を行った結果、プラズマ密度が局所的に周囲よりも減少している領域にほぼ対応して背景電場が局所的に増加していることが見出され、この局所電場がプラズマ圏構造とダイナミクスに重要な役割を演じていることが明らかとなった。

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メディア報道 50

  1. Look! Excessive Tonga volcano eruption leaves a telltale finger-print in area インターネットメディア

    The Media Lord  2022年8月

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    執筆者:本人以外 

  2. An extreme volcanic eruption in Tonga creates a visible fingerprint in space インターネットメディア

    Bolly Inside  Sports News  2022年8月

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    執筆者:本人以外 

  3. Look! Tonga’s large volcanic eruption leaves a transparent fingerprint on the panorama インターネットメディア

    Elondonbuzz  Science  2022年8月

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  4. Looks! The eruption of the extreme Tonga volcano leaves a telltale fingerprint in space インターネットメディア

    Breaking News  Science  2022年8月

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  5. Look at! Extreme eruption of Tonga volcano leaves telltale fingerprint in space インターネットメディア

    The Golden News  2022年8月

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    執筆者:本人以外 

  6. LOOK! EXTREME TONGA VOLCANO ERUPTION LEAVES A TELLTALE FINGER-PRINT IN SPACE インターネットメディア

    INVERSE  2022年8月

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    執筆者:本人以外 

  7. Massive underwater eruption may help predict tsunamis, scientists say インターネットメディア

    AM Costa Rica  2022年7月

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    執筆者:本人以外 

  8. Shockwave caused by Tonga underwater eruption may help scientists predict future tsunami インターネットメディア

    AlphaGalileo  2022年7月

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    執筆者:本人以外 

  9. Tonga Volcanic Eruption May Help Predict Future Tsunami, Study Suggests インターネットメディア

    Insurance Bix  2022年7月

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    執筆者:本人以外 

  10. Así ayudará el volcán de Tonga a predecir tsunamis インターネットメディア

    Faro de Vigo  2022年7月

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    執筆者:本人以外 

  11. Así ayudará el volcán de Tonga a predecir tsunamis インターネットメディア

    Información  2022年7月

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    執筆者:本人以外 

  12. トンガ噴火時も発生「電離層の乱れ」 津波早期検知に期待 名大チーム確認 新聞・雑誌

    毎日新聞  2022年7月

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  13. Así ayudará el volcán de Tonga a predecir tsunamis インターネットメディア

    SPORT  2022年7月

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  14. Así ayudará el volcán de Tonga a predecir tsunamis インターネットメディア

    Elperiodico  2022年7月

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  15. Tonga Volcanic Eruption May Help Predict Future Tsunami, Study Suggests

    Hindiblogger Tech  2022年7月

  16. New detection method could give hours of extra warning of a tsunami, save countless lives – ScienceDaily インターネットメディア

    getaboutcolumbia.com  Science  2022年7月

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  17. トンガ海底火山噴火による電離圏擾乱が高速で伝わるメカニズムを解明 名大ら インターネットメディア

    NEWS SALT  2022年7月

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    名古屋大学は14日、2022年1月に発生した南太平洋トンガ諸島のフンガ・トンガ-フンガ・ハアパイ火山の大規模噴火に伴って生じた気圧波と同期した同心円上の電離圏擾乱じょうらんが地球規模で広がっていく様相を、全球測位衛星システム(GNSS)などのデータを解析して、捉えることに成功したと発表した。

    日本で電離圏擾乱が観測されたタイミングは、音速に近い気圧波が到来する約3時間前だった。これは、オーストラリアから日本に地球の磁力線沿いに1000km/sの速さで電離圏の擾乱が伝わったことを示している。この研究成果は地球科学の総合国際学術雑誌「Earth, Planets and Space」に13日付で掲載された。

    地球大気圏の高度80Km以上の上部には太陽放射によって電離層が形成されていて、全球測位衛星システム(GNSS) 、衛星放送・通信で使われている電波はこの領域を必ず通過する。電離層が激しく乱れる擾乱が発生するとGNSSの位置情報に誤差が生まれることがあり、これを逆手に取ってGNSS受信機網データを活用した電離圏擾乱の研究が進められている。

    電離層は太陽活動による影響を受けるだけでなく、地震、火山噴火、津波、台風などの気象現象といった下層大気で発生した大気擾乱の影響も受ける。これは地震で発生した津波が下層大気を揺さぶることによって大気振動(音波)や大気波動が生成され、それらが上空の電離圏に伝わることで、電離圏電子密度擾乱を引き起こすと考えられている。

    名古屋大学宇宙地球環境研究所 新堀淳樹特任助教らの研究グループは、情報通信研究機構、電気通信大学との共同研究により、世界各地に設置されている約9000台に及ぶGNSS受信機データを解析して全電子数(TEC:電子の柱状数密度)をデータベース化した。また、気象衛星ひまわり8号の赤外輝度温度データと北海道陸別町に設置された電離圏観測用レーダー(SuperDARNレーダー)のデータも使用した。

  18. SCIENCE Shockwave Caused By Tonga Underwater Eruption May Help Scientists Predict Future Tsunamis インターネットメディア

    TECHNO BLENDER  2022年7月

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  19. Shockwave caused by Tonga underwater eruption may help scientists predict future tsunami インターネットメディア

    ScienceDaily  2022年7月

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  20. ONDA DE CHOQUE CAUSADA PELA ERUPÇÃO SUBMARINA DE TONGA PODE AJUDAR OS CIENTISTAS A PREVER FUTUROS TSUNAMIS インターネットメディア

    TERRA RARA  2022年7月

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  21. Tonga Volcanic Eruption May Help Predict Future Tsunami, Study Suggests インターネットメディア

    AKASHSHREE TECH  Science  2022年7月

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  22. Wulkan Tonga wywołał olbrzymią falę! Badacze skorzystali na tym i pokazali, jak przewidywać tsunami

    chip  Tech  2022年7月

  23. The Tonga Volcanic Eruption Might Be a Help in Predicting Your Future Tsunami, According to a Study インターネットメディア

    techmarmot  2022年7月

  24. Schnellere Tsunami-Warnungen aufgrund von GPS-Störungen インターネットメディア

    ICT  2022年7月

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    執筆者:本人以外 

  25. Schnellere Tsunami-Warnungen

    Pressetext  HIGHTECH  2022年7月

  26. Studiare la ionosfera per prevedere gli tsunami インターネットメディア

    Global Science  2022年7月

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    執筆者:本人以外 

  27. Tsunami Prediction Could Become Possible Using Data From Tonga Underwater Volcano Eruption インターネットメディア

    The Science Times  ENVIRONMENT & CLIMATE  2022年7月

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    執筆者:本人以外 

  28. A study suggests that the eruption of the Tonga Volcanic Eruption might help predict the future tsunami インターネットメディア

    list23  TECH  2022年7月

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    執筆者:本人以外 

  29. NEW DETECTION METHOD COULD GIVE HOURS’ EXTRA WARNING OF A TSUNAMI, SAVING COUNTLESS LIVES — SCIENCEDAILY インターネットメディア

    Air Quality Index  2022年7月

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  30. Data From Tonga Volcanic Eruption May Help Us Brace for Future Tsunami インターネットメディア

    Daily Hindustan News  Technology  2022年7月

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  31. Tonga Volcanic Eruption Might Assist Predict Future Tsunami, Research Suggests インターネットメディア

    Frp Bypass Free  2022年7月

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  32. Information from the Tonga eruption might assist predict future tsunamis インターネットメディア

    AllMaa  2022年7月

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  33. Shockwave Caused By Tonga Underwater Eruption May Help Scientists Predict Future Tsunamis インターネットメディア

    My Droll  2022年7月

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  34. Knowledge From Tonga Volcanic Eruption Could Support Us Brace for Upcoming Tsunami インターネットメディア

    Breaking Tech News  Technology  2022年7月

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  35. Data From Tonga Volcanic Eruption May Help Us Brace for Future Tsunami インターネットメディア

    Mondaydaily  2022年7月

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  36. Information From Tonga Volcanic Eruption Might Assist Us Brace for Future Tsunami インターネットメディア

    Dailynewz  Tech  2022年7月

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  37. Tonga Volcanic Eruptions Could Help Predict Future Tsunamis, Research Proposal インターネットメディア

    News7h  Tech  2022年7月

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  38. Knowledge From Tonga Volcanic Eruption Could Assist Us Brace for Future Tsunami インターネットメディア

    Dirrectly  Technology  2022年7月

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  39. Die durch den Tonga-Unterwasserausbruch verursachte Schockwelle könnte Wissenschaftlern helfen, zukünftige Tsunamis vorherzusagen インターネットメディア

    GAMINGSYM GERMANY  2022年7月

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  40. Information From Tonga Volcanic Eruption Could Assist Us Brace for Future Tsunami インターネットメディア

    Growdemy  2022年7月

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  41. Tonga Volcanic Eruption Could Assist Predict Future Tsunami, Examine Suggests インターネットメディア

    The perfectech  Mobile  2022年7月

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  42. Data From Tonga Volcano Eruption May Help Us Cope With Future Tsunamis インターネットメディア

    Nitbuz  2022年7月

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  43. La onda de choque causada por la erupción submarina de Tonga puede ayudar a los científicos a predecir futuros tsunamis インターネットメディア

    Notiulti  2022年7月

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  44. Tonga : l’onde de choc d’une éruption sous-marine pourrait aider à prédire un futur tsunami インターネットメディア

    Generationsnouvelles  2022年7月

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  45. Tonga Volcanic Eruption May Help Predict Future Tsunami, Study Suggests インターネットメディア

    Tech  Science  2022年7月

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  46. Tonga Volcanic Eruption May Help Predict Future Tsunami, Study Suggests インターネットメディア

    REALTIME INDIA  TECHNOLOGY  2022年7月

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  47. Shockwave from Tonga eruption may help predict tsunamis インターネットメディア

    earth.com  2022年7月

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  48. 上空の電子乱れで津波を早く検知可能 トンガ噴火解析 名古屋大 新聞・雑誌

    毎日新聞  2022年7月

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  49. Scientists may be Able to Anticipate Future Tsunamis Thanks to the Tonga Underwater Eruption’s Shockwave インターネットメディア

    ASSIGNMENT POINT  ENVIRONMENT  2022年7月

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  50. Tonga Volcanic Eruption May Help Predict Future Tsunami, Study Suggests インターネットメディア

    gadgets360  Science News  2022年7月

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