研究者詳細 - 塩川　和夫

論文 - 塩川　和夫

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Drift velocities of 150-km field-aligned irregularities observed by the equatorial atmosphere radar 査読有り

Otsuka Y, Mizutani N, Shiokawa K, Patra A, Yokoyama T, Yamamoto M

Antarctic Record 57 巻 ( 3 ) 頁： 369 - 378 2013年

Giant ionospheric disturbances observed with the SuperDARN Hokkaido HF radar and GPS network after the 2011 Tohoku earthquake 査読有り

Ogawa Tadahiko, Nishitani Nozomu, Tsugawa Takuya, Shiokawa Kazuo

EARTH PLANETS AND SPACE 64 巻 ( 12 ) 頁： 1295-1307 2012年12月

Special Issue: Recent Progress in the Vertical Coupling in the Atmosphere-Ionosphere System Preface 査読有り

Pancheva, D; Shiokawa, K; Knizova, P; Wan, WX

JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS 90-91 巻 ( 1 ) 頁： V - VI 2012年12月

Development of low-cost sky-scanning Fabry-Perot interferometers for airglow and auroral studies 査読有り

Shiokawa K., Otsuka Y., Oyama S., Nozawa S., Satoh M., Katoh Y., Hamaguchi Y., Yamamoto Y., Meriwether J.

EARTH PLANETS AND SPACE 64 巻 ( 11 ) 頁： 1033 - 1046 2012年11月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Earth, Planets and Space

We have developed new Fabry-Perot interferometers (FPIs) that are designed to measure thermospheric winds and temperatures as well as mesospheric winds through the airglow/aurora emissions at wavelengths of 630.0 nm and 557.7 nm, respectively. One FPI (FP01), possessing a large aperture etalon (diameter: 116 mm), was installed at the EISCAT Tromsø site in 2009. The other FPIs, using 70-mm diameter etalons, were installed in Thailand, Indonesia, and Australia in 2010-2011 (FP02-FP04) by the Solar-Terrestrial Environment Laboratory, and in Peru (Nazca and Jicamarca) and Alaska (Poker Flat) by Clemson University. The FPIs with 70-mm etalons are low-cost compact instruments, suitable for multipoint network observations. All of these FPIs use low-noise cooled-CCD detectors with 1024 × 1024 pixels combined with a 4-stage thermoelectric cooling system that can cool the CCD temperature down to - 80°C. The large incident angle (maximum: 1.3°-1.4°) to the etalon achieved by the use of multiple orders increases the throughput of the FPIs. The airglow and aurora observations at Tromsø by FP01 show wind velocities with typical random errors ranging from 2 to 13 m s-1 and from 4 to 27 m s-1 for mesosphere (557.7 nm) and thermosphere (630.0 nm) measurements, respectively. The 630.0-nm airglow observations at Shigaraki, Japan, by FP02-FP04 and by the American FPI instruments give thermospheric wind velocities with typical random errors that vary from 2 m s-1 to more than 50 m s-1 depending on airglow intensity. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS).

DOI： 10.5047/eps.2012.05.004

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Reflection height of daytime tweek atmospherics during the solar eclipse of 22 July 2009 査読有り

Ohya, H; Tsuchiya, F; Nakata, H; Shiokawa, K; Miyoshi, Y; Yamashita, K; Takahashi, Y

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

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

We report multipoint observations of daytime tweek atmospherics during the solar eclipse of 22 July 2009. Sixteen and sixty-three tweek atmospherics were observed at Moshiri and Kagoshima, Japan, where the magnitudes of the solar eclipse were 0.458 and 0.966, respectively. This was the first observation of tweek atmospherics during a low-magnitude eclipse (0.458). The average and standard deviation of the reflection height were 94.9 13.7km at Moshiri and 87.2 12.9km at Kagoshima. The reflection height at Moshiri was almost the same as that for normal nighttime conditions in July (96.7 12.6km) in spite of the low magnitude of the eclipse. The reflection height at Kagoshima seems be divided into two parts: propagation across the total solar eclipse path and propagation in the partial solar eclipse path. During the eclipse, we also observed the phase variation in the LF transmitter signals. The average change in the phase delay of the LF signals was 109 for the paths that crossed the eclipse path and 27 for the paths that did not cross the eclipse path. Assuming a normal daytime height for LF waves of 65km, a ray tracing analysis indicates that the variations in phase correspond to a height increase of 5-6km for the paths across the eclipse and 1-2km for partial eclipse paths. The wide range of estimated tweek reflection heights at Kagoshima also suggests a difference in electron density in the lower ionosphere between total and partial solar eclipses. © 2012. American Geophysical Union. All Rights Reserved.

DOI： 10.1029/2012JA018151

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Observation of equatorial nighttime medium-scale traveling ionospheric disturbances in 630-nm airglow images over 7 years 査読有り

Fukushima, D; Shiokawa, K; Otsuka, Y; Ogawa, T

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 117 巻 ( 10 ) 2012年10月

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

[1] We report on nighttime medium-scale traveling ionospheric disturbances (MSTIDs) observed at Kototabang, Indonesia (geographic longitude: 100.3°E; geographic latitude: 0.2°S; and geomagnetic latitude: 10.6°S) during a 7-year period from October 2002 to October 2009. MSTIDs were observed in 630-nm nighttime airglow images by using a highly sensitive all-sky airglow imager at Kototabang. The averages and standard deviations of horizontal phase velocity, period, and horizontal wavelength of MSTIDs observed during the 7 years were 320 ±170 m/s, 42 ±11 min, and 790 ± 440 km, respectively. The occurrence rate of the observed MSTIDs decreased with decreasing solar activity. The average horizontal wavelength of MSTIDs increased with decreasing solar activity. Southward MSTIDs were dominant throughout the 7 years of observations. These facts are consistent with the hypothesis that the observed MSTIDs are caused by gravity waves in the thermosphere. Moreover, we compared the propagation directions of the observed MSTIDs with the locations of tropospheric convection activity for the events where gravity waves producing the observed MSTIDs could have existed in the lower atmosphere. Strong tropospheric convection was found within ±30 degrees from the source directions of MSTIDs in 81% of the MSTID events. In such events, gravity waves were possibly generated from deep convection in the troposphere and directly propagated into the thermosphere. © 2012. American Geophysical Union. All Rights Reserved.

DOI： 10.1029/2012JA017758

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Motion of high-latitude nighttime medium-scale traveling ionospheric disturbances associated with auroral brightening 査読有り Open Access

Shiokawa, K; Mori, M; Otsuka, Y; Oyama, S; Nozawa, S

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 117 巻 ( 10 ) 2012年10月

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

We report for the first time the rapid oscillating motion of nighttime medium-scale traveling ionospheric disturbances (MSTIDs) based on airglow imaging observations at Troms (magnetic latitude: 67.1N), Norway on 8 December, 2009. The MSTIDs appeared in 630-nm airglow images at 1530 UT as wave-like structures south of Troms with a horizontal wavelength of ∼200km and a phase surface of north to south. They moved eastward with velocities of 30-60m/s. The velocity was faster in the poleward-side of the MSTIDs, forming a northeast-southwest phase surface at later times. This phase surface direction is opposite to that of midlatitude MSTIDs. The MSTIDs show sudden oscillations and phase jump in the east-west direction with a timescale of ∼10min at 1730 UT. The oscillations were associated with an auroral brightening observed at the poleward edge of the images and small magnetic field perturbations observed by ground magnetometers. The Doppler measurement of the 630-nm airglow by a Fabry-Perot interferometer at Troms showed a stable southeastward thermospheric wind with a velocity of ∼150m/s. These observations indicate that the MSTID oscillations were linked to auroral electric field in the ionosphere, implying that the observed MSTIDs are ionospheric plasma structures. We suggest that the observed MSTIDs were created by atmospheric gravity waves at the beginning, left as fossil plasma structures even after the gravity wave packet dissipated in the thermosphere, moved eastward according to the background electric field driven by the F-region dynamo, and oscillated associated with the auroral electric field. © 2012. American Geophysical Union. All Rights Reserved.

DOI： 10.1029/2012JA017928

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Magnetospheric responses to the passage of the interplanetary shock on 24 November 2008 査読有り

K-H Kim, D-H Lee, K. Shiokawa, E. Lee, J-S Park, H-J Kwon, V. Angelopoulos, Y-D. Park, J. Hwang, N. Nishitani, T. Hori, K. Koga, T. Obara, K. Yumoto, D. G. Baishev

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 117 巻 ( 10 ) 2012年10月

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

The passage of an interplanetary (IP) shock was detected by Wind, ACE, Geotail, and THEMIS-B in the solar wind on 24 November 2008. From the propagation time of the IP shock at the spacecraft, it is expected that the IP shock front is aligned with the Parker spiral and strikes the postnoon dayside magnetopause first. Using multipoint observations of the sudden commencement (SC) at THEMIS probes, GOES 11, and ETS in the dayside magnetosphere, we confirmed that the magnetospheric response to the IP shock starts earlier in the postnoon sector than in the prenoon sector. We found that the estimated normal direction of the SC front is nearly aligned with the estimated IP shock normal. We also found that the SC front normal speed is much slower than the fast mode speed and is about 22-56% of the IP shock speed traveling in the solar wind. Thus, we suggest that the major field changes of the SC in the dayside magnetosphere are not due to the magnetic flux carried by hydromagnetic waves but to the increased solar wind dynamic pressure behind the shock front sweeping the magnetopause. The SC event appears as a step-like increase in the H component at the low-latitude Bohyun station and a negative-then-positive variation in the H component at the high-latitude Chokurdakh (CHD) station in the morning sector. During the negative perturbation at CHD, the SuperDARN Hokkaido radar detected a downward motion in the ionosphere, implying westward electric field enhancement. Using the THEMIS electric field data, it is confirmed that the westward electric field corresponds to the inward plasma motion in the dayside magnetosphere due to the magnetospheric compression.

DOI： 10.1029/2012JA017871

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Visualization of ion cyclotron wave and particle interactions in the inner magnetosphere via THEMIS-ASI observations 査読有り

K. Sakaguchi, Y. Miyoshi, E. Spanswick, E. Donovan, I. R. Mann, V. Jordanova, K. Shiokawa, M. Connors, J. C. Green

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 117 巻 ( 10 ) 2012年10月

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

Interaction with EMIC (electromagnetic ion cyclotron) waves is thought to be a key component contributing to the very rapid loss of both ring current and radiation belt particles into the atmosphere. Estimated loss rates are heavily dependent on the assumed spatial distribution of the EMIC wave. Statistical maps of the spatial distribution have been produced using in-situ satellite data. However, with limited satellite data it is impossible to deduce the true spatial distribution. In this study, we present ground-based observations using all-sky imager and search coil magnetometer networks, which provide the large-scale distribution and motion of the EMIC wave-particle interaction regions. We observed several spots of isolated proton auroras simultaneously with Pc1/EMIC waves at subauroral latitudes during the expansion phase of a storm-time substorm on 9 March 2008. The isolated auroras were distributed over similar to 4-hours MLT preceding midnight. The POES-17 satellite confirmed enhancements of 30-keV proton precipitations over the isolated auroras. The equatorward motion of the auroras and frequency drift of the wave were consistent with the plasmasphere eroding due to a polar cap potential enhancement modeled by a numerical simulation. We also found that relativistic electron precipitation was not always associated with the isolated aurora, depending strongly on the plasma density profile near the plasmapause. This study shows that the specific distribution of ring current proton precipitation can be visualized through the ground network observations. By combining with upcoming inner-magnetosphere satellite missions, these remote-sensing observations are very important for quantitative understanding of the particle loss in the inner magnetosphere.

DOI： 10.1029/2012JA018180

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Space-time variability of polar cap patches: Direct evidence for internal plasma structuring 査読有り

Dahlgren H., Perry G. W., Semeter J. L., St-Maurice J. -P., Hosokawa K., Nicolls M. J., Greffen M., Shiokawa K., Heinselman C.

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

Observed correlation between pulsating aurora and chorus waves at Syowa Station in Antarctica: A case study 査読有り Open Access

Ozaki, M; Yagitani, S; Ishizaka, K; Shiokawa, K; Miyoshi, Y; Kadokura, A; Yamagishi, H; Kataoka, R; Ieda, A; Ebihara, Y; Sato, N; Nagano, I

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 117 巻 ( A8 ) 頁： 8211 - 8211 2012年8月

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

A high correlation between a pulsating auroral patch and grouped chorus waves was observed on 17 April 2006 at Syowa Station in Antarctica. The spatial distribution of aurora-chorus correlation coefficients is evaluated in order to determine the source region. A pulsating patch at the highest-correlation pixel shows a one-to-one correspondence with the intensity variation of the grouped chorus waves, consisting of successive rising-tone elements with a duration and spacing of 2-3s and 20-30s, respectively. The generation region of the chorus waves is estimated from the latitude and longitude dependence of the equatorial electron gyrofrequencies using the IGRF geomagnetic field model. The extent of the estimated latitude and longitude is consistent with the spatial distribution of the high-correlation aurora-chorus region. The time difference between the chorus waves and the scattered electrons is also evaluated to discuss the validity of the source region. It shows that electrons reached the ionosphere sooner than the associated chorus waves by ∼1 s, consistent with the theoretical value for conjugate pulsating aurora generated at the equator. These results support the hypothesis that pulsating aurora is caused by pitch angle scattering of high-energy electrons by whistler mode chorus waves, via a cyclotron resonance at the equator. These results are the first ground-based observations of high correlations between a spatially extended aurora and chorus waves. © (c)2012. American Geophysical Union. All Rights Reserved.

DOI： 10.1029/2011JA017478

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On post-midnight field-aligned irregularities observed with a 30.8-MHz radar at a low latitude: Comparison with F-layer altitude near the geomagnetic equator 査読有り

M. Nishioka, Y. Otsuka, K. Shiokawa, T. Tsugawa, Effendy, P. Supnithi, T. Nagatsuma, K. T. Murata

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

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

We investigated the relationship between post-midnight F-region field aligned irregularities (FAIs) and F-layer altitude by analyzing data of a 30.8-MHz radar installed 5at Kototabang, Indonesia (0.2 degrees S, 100.3 degrees E; geomagnetic latitude 10.4 degrees S) and an ionosonde installed at Chumphon, Thailand (10.7 degrees N, 99.4 degrees E; geomagnetic latitude 3.3 degrees N). Chumphon is located near the geomagnetic equator on approximately the same meridian as Kototabang. Case studies show that the altitude of the F-layer rose at Chumphon a half hour before the post-midnight FAIs appeared at Kototabang. The Doppler velocity of the E-region FAIs observed simultaneously by the 30.8-MHz radar was downward, indicating that the F-layer uplift was not caused by the electric field. We also investigated seasonal variations of the post-midnight FAI occurrence and the F-layer altitude. Both the post-midnight FAIs and the uplift of the F-layer were frequently seen around midnight between May and August. The seasonal variation of the midnight F-layer uplift around the geomagnetic equator coincided with that of the post-midnight FAI occurrence at Kototabang. These results suggest that the uplift of the F-layer would play an important role in the generation of post-midnight FAIs. We evaluated the linear growth rate of the Rayleigh-Taylor instability based on the altitude of the F-layer observed at Chumphon. The result shows that the uplift of the F-layer can enhance the growth rate because gravity-driven eastward electric current increases. Therefore, we interpret that the observed FAIs were accompanied by plasma bubble, the growth rate of which was reinforced by the uplifted F-layer.

DOI： 10.1029/2012JA017692

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Disappearance of equatorial plasma bubble after interaction with mid-latitude medium-scale traveling ionospheric disturbance 査読有り

Otsuka Y., Shiokawa K., Ogawa T.

GEOPHYSICAL RESEARCH LETTERS 39 巻 ( 14 ) 2012年7月

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

We report simultaneous observations of an equatorial plasma bubble and a Medium-Scale Traveling Ionospheric Disturbance (MSTID) in 630-nm airglow images taken with an all-sky airglow imager at Shigaraki (34.9°N, 136.1°E; dip angle of the geomagnetic field ̃49°), Japan. Clear depletion of the 630-nm airglow intensity was observed as the equatorial plasma bubble propagated eastward, whereas the MSTID, which had a wavefront aligned from northwest to southeast, propagated southwestward. This result indicates that MSTIDs do not propagate at the same velocity as the ambient plasma, which is clearly shown by the eastward motion of the plasma bubbles. We found that the airglow depletion caused by the plasma bubble disappeared when the plasma bubble encountered the MSTID. The plasma depletion could be filled with ambient rich plasma that moved into the plasma-depleted region by E - B drift associated with the MSTID, indicating that MSTIDs are accompanied by electric field perturbations. © 2012. American Geophysical Union.

DOI： 10.1029/2012GL052286

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GPS total electron content variations associated with poleward moving Sun-aligned arcs 査読有り

Jayachandran P. T., Hosokawa K., Shiokawa K., Otsuka Y., Watson C., Mushini S. C., MacDougall J. W., Prikryl P., Chadwick R., Kelly T. D.

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 117 巻 ( 5 ) 2012年5月

Direct three-dimensional imaging of polar ionospheric structures with the Resolute Bay Incoherent Scatter Radar 査読有り

Dahlgren H., Semeter J. L., Hosokawa K., Nicolls M. J., Butler T. W., Johnsen M. G., Shiokawa K., Heinselman C.

GEOPHYSICAL RESEARCH LETTERS 39 巻 ( 5 ) 2012年3月

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

Ionospheric plasma density structures in the dayside F-region of the polar cap are commonly occurring events, but adequate measurements of their formation and evolution have been sparse. With the advent of the advanced modular incoherent scatter radar RISR-N (Resolute Bay Incoherent Scatter Radar) it is now possible for the first time to study the temporal evolution of the plasma properties in the polar cap region in three dimensions, with a spatial resolution of tens of kilometers, from which the plasma rest frame can be experimentally established. We demonstrate the strength of the diagnostic with observations from an event of enhanced plasma density observed over Resolute Bay in December 2009. A colocated all-sky imager showed faint 630.0 and 557.7 nm emission corresponding to the plasma enhancements, and the structures could be traced back to a formation region in the open/closed field line boundary. This new plasma imaging technique will provide important information on the mechanisms controlling the structuring in the high latitude ionosphere. Copyright © 2012 by the American Geophysical Union.

DOI： 10.1029/2012GL050895

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Electron and wave characteristics observed by the THEMIS satellites near the magnetic equator during a pulsating aurora 査読有り

A. Nakajima, K. Shiokawa, K. Sakaguchi, Y. Miyoshi, S. Lee, V. Angelopoulos, O. Le Contel, J. P. McFadden, J. W. Bonnell, K. -H. Fornacon, E. Donovan

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 117 巻 2012年3月

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

Based on conjugate ground and THEMIS satellite observations, we show electron spectra and wave characteristics near the magnetic equatorial plane during a pulsating aurora event on the high latitude side of the auroral oval. The pulsating aurora was observed by a 30-Hz sampled all-sky imager (ASI) at Gillam (56.4 degrees N, 265.4 degrees E), Canada, at similar to 0840-0910 UT on 8 January 2008. The auroral intensity pulsation at the possible THEMIS D (THD) footprints had frequency peaks at similar to 0.1-0.2 Hz. The footprint of THD was in the poleward part of the proton aurora observed by a meridian-scanning photometer. After auroral pulsation began at similar to 0842 UT, both THD and THEMIS E which was near THD in the mid-tail at 11.6-11.8 R-E, observed enhanced field-aligned electron fluxes at energies of 1-10 keV. However, the amplitudes of whistler mode waves and electrostatic cyclotron harmonics (ECH) waves observed by THD with the highest sampling rate of 8 kHz were not significant, showing a marked contrast to the recent report of clear correlation between whistler mode waves and auroral pulsations observed at 5-9 R-E. We suggest that the observed field-aligned electrons, which are probably caused by Fermi-type acceleration associated with earthward plasma flow in the mid-tail plasma sheet, are modulated by some wave processes to cause pulsating auroras.

DOI： 10.1029/2011JA017066

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Polarization of Pc1/EMIC waves and related proton auroras observed at subauroral latitudes 査読有り

Nomura R., Shiokawa K., Sakaguchi K., Otsuka Y., Connors M.

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 117 巻 ( 2 ) 2012年2月

Signatures of moving polar cap arcs in the F-region PolarDARN echoes 査読有り

Koustov A. V., Hosokawa K., Nishitani N., Shiokawa K., Liu H.

ANNALES GEOPHYSICAE 30 巻 ( 3 ) 頁： 441 - 455 2012年

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

Joint observations of the all-sky camera at Resolute Bay (Nunavut, Canada) and the Polar Dual Auroral Radar Network (PolarDARN) HF radars at Rankin Inlet and Inuvik (Canada) are considered to establish radar signatures of poleward moving polar cap arcs "detaching" from the auroral oval. Common features of the events considered are enhanced power or echo occurrence in the wake of the arcs and enhanced spectral width of these echoes. When the arcs were oriented along some of the radar beams, velocity reversals at the arc location were observed with the directions of the arc-associated flows corresponding to a converging electric field. For the event of 9 December 2007, two arcs were poleward progressing almost along the central beams of the Inuvik radar at the speed close to the E × B drift of the bulk of the F-region plasma as inferred from HF Doppler velocities and from independent measurements by the Resolute Bay ionosonde. In global-scale convection maps inferred from all Super Dual Auroral Radar Network (SuperDARN) radar measurements, the polar cap arcs were often seen close to the reversal line of additional mesoscale convection cells located poleward of the normal cells related to the auroral oval. © Author(s) 2012.

DOI： 10.5194/angeo-30-441-2012

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The Energization and Radiation in Geospace (ERG) Project 査読有り

Miyoshi Y., Ono T., Takashima T., Asamura K., Hirahara M., Kasaba Y., Matsuoka A., Kojima H., Shiokawa K., Seki K., Fujimoto M., Nagatsuma T., Cheng C. Z., Kazama Y., Kasahara S., Mitani T., Matsumoto H., Higashio N., Kumamoto A., Yagitani S., Kasahara Y., Ishisaka K., Blomberg L., Fujimoto A., Katoh Y., Ebihara Y., Omura Y., Nose M., Hori T., Miyashita Y., Tanaka Y. -M., Segawa T.

DYNAMICS OF THE EARTH'S RADIATION BELTS AND INNER MAGNETOSPHERE 199 巻頁： 103 - 116 2012年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Geophysical Monograph Series

The Energization and Radiation in Geospace (ERG) project for solar cycle 24 will explore how relativistic electrons in the radiation belts are generated during space storms. This geospace exploration project consists of three research teams: the ERG satellite observation team, the ground-based network observation team, and the integrated data analysis/simulation team. Satellite observation will provide in situ measurements of features such as the plasma distribution function, electric and magnetic fields, and plasma waves, whereas remote sensing by ground-based observations using, for example, HF radars, magnetometers, optical instruments, and radio wave receivers will provide the global state of the geospace. Various kinds of data will be integrated and compared with numerical simulations for quantitative understanding. Such a synergetic approach is essential for comprehensive understanding of relativistic electron generation/loss processes through crossenergy and cross-regional coupling in which different plasma populations and regions are dynamically coupled with each other. In addition, the ERG satellite will utilize a new and innovative measurement technique for wave-particle interactions that can directly measure the energy exchange process between particles and plasma waves. In this paper, we briefly review some of the profound problems regarding relativistic electron accelerations and losses that will be solved by the ERG project, and we provide an overview of the project. © 2012. American Geophysical Union. All Rights Reserved.

DOI： 10.1029/2012GM001304

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Auroral Signatures of the Dynamic Plasma Sheet 査読有り

Keiling, A; Shiokawa, K; Uritsky, V; Sergeev, V; Zesta, E; Kepko, L; Ostgaard, N

AURORAL PHENOMENOLOGY AND MAGNETOSPHERIC PROCESSES: EARTH AND OTHER PLANETS 197 巻頁： 317 - + 2012年

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 Monograph Series

Understanding the physical connections of the coupled magnetosphere- ionosphere system will result in a more complete explanation of the aurora and will further the goal of being able to interpret the global auroral distributions as a dynamic map of the magnetosphere. Significant advances have been made in recent years toward this goal. In this chapter, we briefly review, while focusing on recent observations, selected auroral phenomena that are driven by magnetospheric processes. These include expansion of substorm aurora, plasma sheet waves and auroral modulations, ballooning instability and auroral beads, dipolarization/plasma injections and the auroral bulge, poleward boundary intensifications and auroral streamers, vortical flows and auroral spirals, and plasma flows prior to auroral onset. In addition, other auroral phenomena, such as auroral arcs, diffuse auroras, auroral asymmetry/conjugacy in the conjugate hemispheres, and auroral magnetospheric currents, are highlighted here but expanded in other chapters of this monograph for in-depth reviews. © 2012. American Geophysical Union. All Rights Reserved.

DOI： 10.1029/2012GM001231

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