Authorship：Principal investigator 

Grant amount：\488930000 （ Direct Cost: \376100000 、 Indirect Cost：\112830000 ）

In this project, which is named as "PWING", we installed a longitudinal observation network at eight ground-based stations at subauroral latitudes at magnetic latitudes of about 60 degree, in order to monitor longitudinal distribution of particle precipitation and ULF/ELF/VLF waves at frequencies from 0.1Hz to 10 kHz from the inner magnetosphere. We combine these longitudinal network observations with observations by satellites in the inner magnetosphere, such as, Arase and Van Allen Probes, and with global modeling. Using these comprehensive observations and modeling, we have provided various quantitative understandings of dynamical variation of plasma and waves in the inner magnetosphere and contribute to the safe and stable space use.

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Authorship：Coinvestigator(s) 

This research group focused on "space radiation", "ionospheric disturbance", and "geomagnetically induced current" which are the most important space weather phenomena in geospace. The main achievements of this group are as follows. 1) Understanding of wave-particle interactions in the radiation belts that cause large flux enhancement and loss of energetic electrons by the Arase in-situ observations and newly developed simulations, 2) Development of forecast system that calculates ionospheric disturbances for a next few days, 3) Development of physical simulation codes for GIC in Japan islands, which calculates highly accurate GIC variations.

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Authorship：Collaborating Investigator(s) (not designated on Grant-in-Aid) 

We aim to reveal the elevation distribution of auroral polarization along the magnetic meridian by using a newly developed wide field auroral polarization imaging spectrometer. IWe also developed a calibration light system to validate apparent polarization caused by atmospheric scattering and instrument. We installed the instrument at Pokar Flat Research Range, Alaska in November of 2015 and took many calibration data for various field-of-views. Using the calibration data, we evaluated polarization degree with an accuracy better than 0.2 percent. We obtained the linear polarization degree of 630 nm aurora as 1.6 +/- 0.9 percent. For most cases, polarization degree showed a tendency that maximized at the low elevation angle, and decreases as the elevation angle increases. In addition, we contributed the international collaboration with Norway by coordinated EISCAT-radar and optical observations. 4 master students and 2 undergraduate students were graduated based on this study.

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Authorship：Principal investigator 

Grant amount：\38350000 （ Direct Cost: \29500000 、 Indirect Cost：\8850000 ）

・ロシアのZhigansk観測点において、誘導磁力計による定常観測を平成28年9月14日より開始し、良好なデータが取得できていることを確認した。ロシアのZhigansk観測点を管轄するヤクーツクのIKFIA研究所に、平成28年9月末にVLFアンテナ、高感度全天カメラを送付した（平成27年度の本計画の繰り越し分による実施）。また、関連機器による定常観測が行われている既存の観測点であるアサバスカ、トロムソ、マガダン、パラツンカ、レゾリュート、国内の母子里、陸別、信楽、鹿児島、佐多などの自動観測を維持・継続した。
・アサバスカ、マガダン、パラツンカの誘導磁力計による5年間の同時観測データを統計的に解析して、Pc1帯地磁気脈動の振幅変調の観測点ごとに違いの季節・太陽活動度・地方時・地磁気活動度などへの依存性を明らかにした。この結果から、この波動の振幅変調が磁気圏ではなく電離圏の伝搬中にうなりによって発生していることを示唆した。また、アサバスカで1年間に観測されたVLF/ELF帯波動の統計解析を行い、この波動の季節・地方時・地磁気活動度などへの依存性を明らかにした。これらの波動は、人工衛星に悪影響を及ぼす放射線帯粒子の加速や消失を引き起こしていることがわかっており、今回の結果は、この加速・消失過程の時間・空間変化に示唆を与えるものである。
・なお、本計画は、研究代表者が平成28年度から別の特別推進研究の代表者になったために、平成28年度途中で廃止になった。本計画で予定されていたカナダ中部のアサバスカ、カナダの東海岸、及び、ロシアのZhigansk観測点における光学・電磁場計測は、この特別推進研究によって引き続きおこなわれることになった。
28年度が最終年度であるため、記入しない。
28年度が最終年度であるため、記入しない。

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Authorship：Collaborating Investigator(s) (not designated on Grant-in-Aid) 

We investigate mechanisms to cause modulation of the pulsating aurora based on high-speed camera (EMCCD/s-CMOS) and ground-based loop antenna observations at Poker Flat Research Range at Alaska, US and Athabasca, Canada. The observation data showed that the main modulation and internal modulation of the pulsating aurora are caused by chorus bursts and rising tone elements, respectively. Moreover, we investigate comparative study between the precipitating electrons measured by low-altitude satellites and computer simulations. As a result, we identify relationship between energy spectrum of precipitating electrons and frequency spectrum of chorus waves.

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Authorship：Principal investigator 

Grant amount：\19890000 （ Direct Cost: \15300000 、 Indirect Cost：\4590000 ）

In this study we have installed new loop antennas (100-kHz sampling) to measure VLF/ELF chorus waves and auroral cameras (30-100 Hz sampling) at subauroral latitudes in Canada since 17 February, 2012. These observations reveal several previously unknown features of VLF/ELF emissions and their relation to pulsating auroras at subauroral latitudes. Routine measurements of VLF/ELF and auroras have been carried out since then, and statistical features of VLF/ELF waves have been obtained at subauroral latitudes including their relation to local time, magnetic activity, and solar wind conditions. Comparisons with conjugate satellites in the magnetospheric equatorial plane are also on going.

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Authorship：Collaborating Investigator(s) (not designated on Grant-in-Aid) 

The plasma in the polar ionosphere often forms a mesoscale structure through various processes. In this study we made an all-sky imager having an ability to observe the mesoscale plasma structure and the relevant auroral structure at high time resolution, and analyzed data that were obtained from the imager. We identified the occurrence characteristics of the high-density region in the polar cap, and the nature of its structuring. We also found unprecedented spatial and temporal characteristics of the particle precipitation in the cusp.

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Authorship：Collaborating Investigator(s) (not designated on Grant-in-Aid) 

By using EISCAT radars located in northern Scandinavia and Svalbard together with other radars (MF and meteor) as well as several optical instruments (sodium LIDAR, all-sky imagers, FPI, photometer, narrow TV imagers), we have conducted a wide range of research on the geospace. Over the four years from April 2010 to March 2014, we conducted more than 40 special experiments (SPs) for 865 hours. Part of SPs were made as international collaborative experiments with other associate countries. We have obtained new findings about several topics: Cowling channel, polar cap patch, vertical oscillation of the polar ionosphere, ion-neutral collision frequency, auroral heating, travelling ionospheric disturbances. We have published 57 scientific papers.
The EISCAT_3D radar is the next generation IS radar planed by the EISCAT community. We have discussed the EISCAT_3D project with Japanese colleagues as well as foreign colleagues, and have summarized a Japan's science plan using the EISCAT_3D.

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Authorship：Collaborating Investigator(s) (not designated on Grant-in-Aid) 

Equatorial Spread-F (ESF) is a one of the most intense ionospheric disturbance that causes severe scintillation to the satellite-ground communications, and degradation of the GPS locations. In this study we deployed large -area observation network of the ionosphere from Asia and Pacific regions by means of radars, nightglow imagers, and satellite-ground beacon receivers. We investigated yet-unknown day-to-day variability of ESF , and found that the ESF is generated from the enhanced Large -Scale Wave Structure (LSWS) of the ionosphere. We also found detailed behavior of ESF at post -midnight period that enhances under the low-solar conditions.

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Authorship：Principal investigator 

Grant amount：\47840000 （ Direct Cost: \36800000 、 Indirect Cost：\11040000 ）

We have obtained various interesting results on the dynamical variations of the upper atmosphere at altitudes of 80-300 km using multi-point observation of nighttime airglow by 5 Fabry-Perot interferometers and more than 10 al-sky airglow imagers at Russia, Canada, Japan, Norway, Indonesia, Thailand, and Australia. Outstanding examples of the results are (1) various dynamical variations of medium-scale traveling ionospheric disturbances at subauroral latitudes, (2) evidence of duct propagation of small-scale gravity waves in the mesopause region, (3) evidence of a typhoon-induced small-scale gravity wave propagation to the mesopause region, and (4) relationship of eastward propagation of equatorial plasma bubbles and eastward thermospheric wind.

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Authorship：Coinvestigator(s) 

We conduct two campaign observations of high-time resolution all-sky auroral imaging at multi-point stations in the Canadian arctic using 1/30-sec sampled cameras, in addition to the automated routine measurements of monochromatic all-sky cameras. We also combine these observations with the THEMIS satellite measurements. From these observations we obtain fine-scale structures and their development of auroras at the beginning of auroral substorms, as well as detailed characteristics of polar-cap plasma structures.

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Authorship：Collaborating Investigator(s) (not designated on Grant-in-Aid) 

The interaction between the ionospheric plasma and thermospheric neutral winds in the mid-and high-latitude region was investigated using the SuperDARN HF radar network. The main subjects of this project are : 1) dynamics of sub-auroral polarization streams, 2) large and medium scale traveling ionospheric disturbances, and 3) coseismic ionospheric disturbances.

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Authorship：Collaborating Investigator(s) (not designated on Grant-in-Aid) 

A micro-satellite of the Japanese mission was successfully launched from Baikonur Cosmodrome in Kazakhstan on August 23, 2005. We can simultaneously observe spatial distribution and time variation of fine aurora emissions associated with auroral electron precipitation and ionospheric ion outflows with a full pitch-angle coverage and a high-time resolution. Our Reimei team has also started some collaborative observations with EISCAT, all-sky cameras, and SuperDARN. Almost every new moon interval, we have been achieving simultaneous observations with Reimei and the ground-based instruments.

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Authorship：Principal investigator 

Grant amount：\3100000 （ Direct Cost: \3100000 ）

昨年度に引き続き、駆動回路及びMIセンサを研究代表者のグループの研究室内で製作し、回路定数、感度、コイルの巻数を変えて動作テストを繰り返し、磁場を感知して、正常に駆動する回路を製作した。昨年度までに行ってきたMIセンサ及び駆動回路の1次・2次試作では、磁気シールドケース内でのDC磁場変動は数百nT以上もあったが、3次試作では、この値が6.2nT程度の変動にまで改善された。また3次試作最終回路のACノイズレベルは、0.64nT/Hzであった。DC安定度については、定磁場基準のフィードバック、MI出力パルスの積分化、MIセンサに交流磁場を印加するなどの対策が効いているものと思われる。しかし、DC安定度が増したとはいえ、周辺の環境変化(温度・湿度変化等)に耐えられるほどの安定度はなく、センサを移動させたりするとDCオフセットが大きく変化する、という特徴は変わらない。また、現在のACノイズレベルの高さでは、弱いもので0.01nT程度の振幅を持つPc1帯の地磁気脈動をとらえるのは難しい。3次試作中、ACノイズレベルの低減に努めたが、それでも0.05nT/Hzが最高であった。ノイズレベルの高さの大きな要因の一つは、MIパルスのサンプリングに使っているアナログスイッチが出しているノイズであり、このアナログスイッチのノイズ低減方法を考えることが今後の課題であることがわかった。

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Authorship：Principal investigator 

Grant amount：\16840000 （ Direct Cost: \14500000 、 Indirect Cost：\2340000 ）

We installed all-sky cooled-CCD imagers and induction magnetometers at Magadan and Paratunka in Far-East Russia in 2007-2008. By combining pre-existing imagers and the SuperDARN Hokkaido radar and newly-installed induction magnetometers in Japan, we developed a latitudinal chain of ground-based stations to observe the upper atmosphere and geospace. Using these ground-based observations as well as satellite observations, we investigate storm-time broadband electron precipitation, which can cause low-latitude red auroras, and ionospheric disturbances in the subauroral region to middle latitudes.

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Authorship：Collaborating Investigator(s) (not designated on Grant-in-Aid) 

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Authorship：Collaborating Investigator(s) (not designated on Grant-in-Aid) 

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Authorship：Coinvestigator(s) 

Two all-sky airglow/aurora imagers were installed at two Canadian stations at Resolute Bay(RSB)and Athabasca observed polar-cap plasma patches almost always(ATH))in 2005, At RSB, we always during southward IMF periods, From two-dimensional cross-correlation analyses, we determined velocity vectors of the patches, which indicates the ionospheric convection vector, that showed high correlation with the IMF-By and -Bz variations. At ATH, we often observed isolated proton arcs and Stable Auroral Red (SAR) arcs, which were located equatorward of the amoral oval The appearance of the isolated proton arcs was highly correlated with the Pc 1 geomagnetic pulsations measured simultaneously at ATH, suggesting interactions between the electromagnetic ion cyclotron (EMK) waves and protons in the vicinity of the plasmapause and the ring current. Similar interactions without waves were also suggested for the SAR arcs, which appeared after the substorm expansion phase even without geomagnetic storm. These observations show promising capability monitor magnetospheric processes from the ground stations, whit would contribute to the future satellite projects such as THEMES, ERG, and Scope/Xscale

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Authorship：Coinvestigator(s) 

Multinationally coordinated observations have been conducted along the 210 deg. magnetic meridian from high latitudes through middle and low latitudes to the equatorial region, spanning L=8.50-1.00, and along the magnetic dip equator, in cooperation with more 30 organizations in Australia, Brazil, Canada, Indonesia, Japan, Micronesia, Papua New Guinea, Peru, Philippines, Russia, Taiwan, Vietnam, and the United States. During the period of 2003-2005, the following multi-nationally coordinated observations and research project were performed ;
(1)In order to clarify the relationships of magnetospheric phenomena in the polar and equatorial regions, we conducted magnetic and electric field observations in Siberia, Alaska, Philippines, Guam, and Yap in the 210 MM network, and negotiated with the institutes in Canada, Brazil and Peru for collaborative magnetic observations.(2)Optical and magnetic equipments in Canada were re-used for the global network observations. (3)Magnetic observations at middle- and low-latitude stations in Hawaii, Papua New Guinea, Indonesia, and Australia in the Pacific region were also carried out to study the propagation and transfer processes of magnetospheric phenomena from the polar to equatorial regions. (4)Especially, electromagnetic observations along the dip equator in the west Pacific region at Cebu and Davao in Philippines, at Yap, Guam and Christmas Island, were started to investigate dynamics of the equatorial electro-jet current and the associated phenomena. (5)For effective data analyses and exchanges with the satellites and the other ground-based networks, the investigators of this project were dispatched to the international meetings. (6)Summary report of research results was published in March, 2006.
From the multinationally coordinated observations along the 210 deg. magnetic meridian from high latitudes to the equatorial region, and along the magnetic dip equator, we could get important network data to study the geospace environment change by energy and momentum transfer from the solar wind into the equatorial Ionosphere.

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Authorship：Coinvestigator(s) 

The goal of this project is to clarify various spatial and temporal scales of variations, especially variations of atmospheric waves and associated constituent variations, in the mesosphere lower thermosphere (MLT) region by ground-based using radio and optical observation in the Japan, USA and Brazil as well as satellite observations.
From coordinated observations at Shigaraki MU radar site, relations between atmospheric gravity waves and variations of airglow emission profiles have been revealed. A new OH all-sky imager has been developed and coordinated observations with a sodium lidar and two imagers have been carried out (CO2 imager campaign) in Colorado, USA. Relations between ripple structures in the airglow image and atmospheric stability have been clarified.
Associations between troposheric disturbance and gravity waves in the MLT region have been found by observations and ray-tracing using airglow imaging observations in Japan, USA and Brazil. Effect of atmospheric tides are also discussed.
Non-migrating tides has been studied using radar, satellite observations and a GCM model, and zonal variability of airglow image characteristics has been suggested. Three-dimensional simulation has clarified breaking gravity waves and ripple structures in the airglow.
As mentioned above, the results of this project is not limited to the simple output of coordinated observations and spread over a wider research region, which would further stimulate future collaboration between Japan, USA and Brazil in the upper atmosphere region.

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Authorship：Coinvestigator(s) 

We have been conducted ground-based observations of the ionosphere and thermosphere in Indonesia, Japan, and Australia We paid special attention to 100-1000 km scale disturbances in the equatorial F-region ionosphere and thermosphere, i.e., medium-scale traveling ionospheric disturbances (MSTIDs) and plasma bubbles. MSTIDs detected with a 630-nm all-sky imager at Kototabang in Indonesia appear within and in the south of the equatorial F-region anomaly crest with a high occurrence in May and June, and have, on the average, a phase velocity of 300 m/s toward the south and a wavelength of 700 km. Plasma bubbles moving eastward at about 100 m/s have a scale of about 100 km with spacings of 200-250 km, and are embedded within plasma structures with an east-west scale of about 1000 km. MSTIDs and giant plasma bubbles can be simultaneously detected at lower midlatitudes in Japan and Australia that are connected by the geomagnetic field line, and are very identical in appearance in the both hemispheres. Equatorial ionospheric scintillations of GPS radio waves associated with plasma bubbles have been continuously monitored at Kototabang. They appear predominantly from sunset to midnight in equinoctial months, a characteristic of equatorial plasma bubble occurrences. To investigate possible dynamical coupling between the ionosphere/thermosphere and troposphere over the equator, we compare the scintillation activity and Earth's brightness temperature (Tbb) variation over the Indian Ocean. The results indicate the following: 1) the scintillation occurrence and Tbb variation are modulated by planetary waves with periods from a few days to several tens of days, and 2) the scintillation tend to be enhanced when high and low Tbb regions appear in the west of Kototabang, suggesting that plasma bubbles may be seeded by atmospheric gravity waves propagating upward from the troposphere.

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Authorship：Principal investigator 

Grant amount：\12200000 （ Direct Cost: \12200000 ）

(1)We have investigated a nighttime medium-scale traveling ionospheric disturbance(MSTID) observed by an airglow imager at Shigaraki, Japan. The structure was identified in the airglow images of OI (630.0 nm and 777.4 nm) as NW-SE band structures moving southwestward with a velocity of 50 m/s. We found that an electric field oscillation of -1.2 mV/m was sufficient to reproduce the observed airglow amplitudes. This modeled electric field was comparable to that observed by the DMSP F15 satellite as it passed over Shigaraki during our observing period. The DMSP ion drift data show that the oscillation of the polarization electric field correlated with the MSTID structure in the airglow image.
(2)We found a large-scale equatorial F-region airglow depletions extending to low-midlatitudes in both hemispheres. The observational sites were located at low-midlatitude geomagnetic conjugate points. Clear depletions of 630.0-nm airglow intensity due to equaterial plasma bubbles were simultaneously observed with two all-sky imagers at Sata, Japan (magnetic latitude 24° N), and its geomagnetic conjugate point, Darwin, Australia (magnetic latitude 22° S). These observations indicate that plasma depletions in the equatorial ionosphere elongate along the geomagnetic field lines.
(3)We report for the first time simultaneous observations of MSTIDs at geomagnetic conjugate points in both hemispheres, using two all-sky airglow imagers at midlatitudes. A 630-nm all-sky imager at Sata, Japan, detected MSTIDs with a wave front elongated from NW to SE. MSTIDs with a wave front elongated from SW to NE were observed at the geomagnetic conjugate point, Darwin, Australia. The MSTID structures mapped from Darwin to its magnetic conjugate points along the geomagnetic field lines coincide closely with those in the Sata images. This result suggests that polarization electric field plays an important role in the generation of MSTIDs.

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Authorship：Coinvestigator(s) 

In this research, we have developed a real-time MAGnetic Data Acquisition System of Circum-pan Pacific Magnetometer Network, i.e. MAGDAS/CPMN system in Kyushu University. On the basis of the results, new fluxgate-type magnetometers and their data acquisition system from overseas sites to Japan will be constructed in the SERC, Kyushu University until the end of 2004. Magnetic field digital data(H+δH, D+δD, Z+δZ, F+δF) are obtained with the sampling rate of 1/16 seconds, and then the averaged data are transferred from the overseas stations to the SERC, Japan in real time. The long-term inclinations(I) of the sensor axes are measured by two tilt-meters with 0.2 arc-sec resolution. The temperature (T) inside the sensor bloc is also measured. The GPS signals are received to adjust the standard time inside the data logger/transfer unit.
These data are logging in the Compact Flash Memory Card of 1 GB. Every day, the data logger at an overseas site generates a file containing averaged 1-see magnetic data (H,D,Z,F) and a file containing the averaged 1-minmagnetic data and inclination and temperature data (I,T) of the magnetometer sensor. The file size of the 1-sec data is less than 1.5 MB/day. The file-size of the 1-min data is less than 50KB. If the communication line at the site does not allow a fast-enough connection, the data logger sends only the 1-min file to the SERC every day ; if the connection is fast enough, the data logger sends both the 1-min file and the 1-sec file to the SERC every day. In fact, the data transfer does not have to be on a daily basis : That is, the data-transfer interval can be set to any value between 10 minutes and 1 day, depending on the condition of the following communication lines. The MAGDAS data can be transferred from the overseas stations to the SERC, Japan, by using three possible ways; special line for INTERNET, telephone line and Satellite telephone lines.

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Authorship：Principal investigator 

Grant amount：\2100000 （ Direct Cost: \2100000 ）

We have investigated various characteristics of magnetic and plasma fluctuations for 21 events of substorm-associated near-Earth dipolarization at Xgsm=-8 --11 Re and |Ygsm|<5 Re, using high-time-resolution data for the magnetic field (1/16 s), plasma moment (12 s), and electric field (3 s) measured by the GEOTAIL satellite in 1995-2000. The dipolarizations are always accompanied by intense fluctuations of the magnetic field. The amplitude of the fluctuations is larger for smaller B (closer to the cross-tail current sheet). We found several events in which the magnetic field elevation angles decreased rapidly prior to the dipolarization (explosive growth phase (EGP)-like features). The magnetic fluctuations are not sinusoidal curves but are spikes of a sudden decrease and increase with a time scale of seconds. In quite a few cases, the fluctuations are accompanied by Earthward convective plasma flow. The spectral shape of the fluctuations has a steeper slope (f^-2.7) at 1.0-0.2 Hz than at 0.01-0.2 Hz (f^-2.0). From the correlation between plasma velocity and magnetic field fluctuations, we estimate the parallel scale sizes of waves with periods of 60 s and 15 s to be about 10 Re and 5 Re, respectively. For the 60-s waves, the magnetic and plasma pressure variations are clearly anti-phase. The total pressure tends to decrease gradually before the dipolarization and increase during and after the dipolarization.

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Authorship：Coinvestigator(s) 

1) Routine observation of airglow image has been started since July 2000 at Sata (Kagoshima) and since October 2001 at Darwin (Australia) during this research period. Together with Rikubetsu (Hokkaido) and Shigaraki (Siga) (since October 1998), these four stations continue taking airglow images. Campaign observations were carried out at Okinawa (August, 1999) and Tanegashima (August 2002). A Fabry-Perot interferometer (FPI) measures mesospheric and thermospheric wind since October 2000 at Shigaraki. Quick-look plots of these routine measurements are available at http://stdb2.stelab.nagoya-u.ac.jp/omti/.
2) Results for gravity waves in the mesopause region : a) Climatology (occurrence, propagation directions, and so on) of gravity waves were obtained from statistical study of airglow images at these Japanese and Australian stations. b) Localized (isolated) structure was found in the mesopause region. We suggest that nonlinear wave-wave interactions caused this structure. c) Heights of gravity waves and airglow emissions were determined by a triangulation technique using airglow images obtained at two nearby sites.
3) Results for medium-scale traveling ionospheric disturbance (MSTID) : a) Climatology (occurrence, wavelength, propagation directions, and so on) of MSTIDs were obtained from statistical study of airglow images in Japan. b) Based on a comparison of satellite data and model calculations including background wind information from FPI, we show that the MSTIDs are not directly caused by gravity waves, but correspond to the electric field structure generated by some ionospheric instability. c) Based on simultaneous airglow imaging observations in Japan and Australia, we found that this electric field structure propagates along magnetic field line between the two hemispheres.
4) Results for large-scale traveling ionospheric disturbance (LSTID) : LSTIDs were identified as 630-nm airglow enhancement during magnetic storms. We showed on the basis of model calculations and direct wind measurements that this LSTID was caused by poleward wind enhancement (propagating equatorward) in the thermosphere. We also argued from the observed auroral zone energy input that simple wind generation model in the auroral zone did not explain the observed LSTID features.
5) Based on the simultaneous airglow imaging observations in Japan and Australia, we found symmetric plasma bubble structures between the two hemispheres.
6) During the research period, we have succeeded observations of low-latitude aurora 11 times in the northern part of Japan (Hokkaido). Two of them were observed in the mainland of Japan (Shigaraki), making a record of lowest latitude of auroral measurement in Japan.
7) From simultaneous measurement of mesospheric wind by the FPI and the MU radar, temporal variations of airglow emission height were estimated.

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Authorship：Coinvestigator(s) 

By using EISCAT radars together with satellites, we have investigated mainly three aspects of ion upflow phenomena in order to understand the generation mechanisms of ion up flow. The first step was to investigate the relationship between ion upflow and particle precipitation which is different between several magnetospheric regions. The second step was to investigate the relationship between ion upflow and heating, from the macroscopic point of view. The third step was to investigate the characteristics of naturally enhanced ion-acoustic lines (NEIALs), which may be caused by plasma instabilities and are strongly related to ion upflow from the microscopic point of view. We have examined the regions where dayside field-aligned (FA) ion upflows occur, based on a statistical analysis using approximately 170 simultaneous events between the ESR and the DMSP satellites. This systematic analysis for ion upflow has never been examined. We found that ion up flows occur not only in the cusp and cleft (the low altitude portion of the low-latitude boundary layer (LLBL)) which have been considered as ion up flow regions, but also in the topside ionosphere connected to the mantle region. Ion upflows seldom occur either in the Boundary Plasma Sheet (EPS) or in the Central Plasma Sheet (CPS) in the dayside high latitudes. Almost all of the events in which the average FA ion velocity is more than 100 m s^<-1> are associated with sufficient soft electron precipitation (differential energy flux of electrons at 100 eV > 10^7 eV cm^<-2> s^<-1> sr^<-1> eV^<-1>). Although soft electron precipitation also sufficiently exists in the EPS, the ion velocities are mostly less than 100 m s^<-1>. The present results indicate that soft particle precipitation is the predominant energy source driving ion up flow in the topside ionosphere, but it works on ion upflow effectively in the higher latitude regions in the dayside and not in the EPS. In addition, plasma heating associated with FA ion upflow in the daysjde topside ionosphere has been examined using data obtained simultaneously with the ESR and the EISCAT VHP radar, and also the wave number (k)-dependence of the received power in high signal-to-noise ratio (SNR) conditions, occurring for NEIALs and for real satellites, has been investigated.
The results from these three investigations lead to the conclusion that the energy of soft electron precipitation is considered as the main source of the ion up flow. The energy of soft particle precipitation is supplied to the ions in the topside ionosphere via wave-particle interaction, such as wave-induced transverse ion heating, and upward parallel electric field due to anomalous resistively produced by plasma turbulence. Thus generation mechanisms of ion upflow must have the transversely ion heating and the upward acceleration by wave-particle interaction while the induced plasma waves decay. In addition to direct precipitation effects, namely enhanced ambipolar diffusion and heat flux, wave-particle interaction may hence play an important role in driving ion upflow.

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Authorship：Coinvestigator(s) 

This research program was started as practical stage of a research previously made for surveying and developing instruments to utilize Internet for better management of and stable-speedy collection of data form a golobal network system presently operated for observing magnetic field variations and auroral images in the northern polar region.
Topical upcomes of this program are as follows:
1. remote data collection of magnetic field by satellite link or telephone line will be enhanced in coming years form sites in auroral zone and sub-auroral zone of the western Canada in cooperation of The University of Tokyo and University of Alaska. 2. Magnetic field data acquired at Rocky Point site nearby Victoria was started and is now ??ntinuously transferred by a cellular phone link to a Unix computer accessible from Internet. 3. Expeirments of collection of auroral images were made by displaying auroral images on a wed home page and by regular transfer of image files from two location, Longyearbyen and NyAlesund, in the Spitsbergen Island. We had frequent data losses even for a data rate of a picture(typically 10kB)par one minute mainly due to a narrow capacity of communication line between the island to the main land of Norway. (4)an automatic data logging system for an induction magnetometer was installed and operated at Uzuri, the very quiet site in the northern end of the Olkohn is land in the Lake Bykal in collaboration with the Institute of Solar-Terrestrial in Irkutsk although data is now transferred to us by hand typically at conferences. (5)data collection based on Internet form Eureka, Ellesmer Island, the remotest site in the central polar cap, will be realized based on license agreement to use network system of Canadian Atmospheric Environment Service as s cooperation program with communication Research Laboratory of Japan. Quite many possibilities of solution to our requirement are available and are changing rapidly so it is very important to restart this kind program to catch up rapid changes and expansion of Internet.

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Authorship：Coinvestigator(s) 

Multinationally coordinated observations have been conducted along the 210 deg.magnetic meridian from high latitudes through middle and low latitudes to the equaatorial region, spanning L=8.50-1.00, and along the dip equator, in cooperation with more 30 organizations in Australia, Brazil, Canada, China, Indonesia, Japan, Korea, Micronesia, Papua New Guinea, Peru, Philippines, Russia, Taiwan, Vietnam, and the United States. The organized ground network data of magnetic fields make ita possible (1) to study the magnetospheric responses to various changes in the solar wind, by distinguishing bitween temporal changes and spatial variations in the phenomena, and (2) to clarify the global propagation, transfer, and coupling processes of magnetospheric phenomena from the polar to equatorial regions.
During the period of 1996-1997, the following multinationaily coordinated observations and research project were performed ;
(1) In order to clarify the relationships of magnetospheric phenomena in the polar and equatorial regions, we coducted magnetic and electric field observations in Siberia, Alaska, Philippines, Guam, and Yap in the 210 MM network, and nagotiated with the institutes in Canada, Brazil and Pere for collaborative magnetic observations.
(2) Optical and magnetic equipments (i.e., all-sky TV camerain, induction and flux gate magnetometers) in Canada, which were installed by University of Tokyo and Nagoya University during the STEP period, were re-used for the global network observations.
(3) Magnetic observations at middle-and low-latitude stations in Korea, Hawaii, Papua New Guinea, Pohnpei, Indonesia, and Australia in the Pacific region were also carried out to study the propagation and transfer processes of magnetospheric phenomena from the polar to equatorial regions.
(4) Especially, electromagnetic observations along the dip equator in the west Pacific region at Cebu and Davao in Philippines, at Pohnpei, Yap, Guam and Christmas Island in Micronesia, were started to investigate the dynamics of equatorial electrojet current and the associated phenomena.
(5) For effective data analyzes and exchanges with the ISTP satellites and the other ground-based networks, the investigators of this project were dispatched to the Western Pacific Geophysical Meeting, held in Australia in 1996, and the IAGA,held at Uppsala in 1997.
(6) Summary report of research results was published in March, 1998.
From the multinationally coordinated observations along the 210 deg.magnetic meridian from high latitudes to the equatorial region, and along the dip equator, we could get important network data to study the magnetospheric responses to various changes in the solar wind, and clarify the global propagation and transfer characteristics of magnetospheric phenomena in the frequency range of DP2-Pc3, from the polar to equataorial regions.

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Authorship：Coinvestigator(s) 

Observations of optical phenomena at high altitude above thunderstorms using a multichannel high-speed photometer and image intensified CCD cameras were carried out at Yucca Ridge Station (40゜40'N, 104゜59'W), Colorado. The new measurements indicate that diffuse optical flashes with a duration of <1ms and a horizontal scale of 〜100-300km occur at 75-105km altitude in the lower ionosphere just after the onset of sprites. Here we designate these events as "elves" to distinguish them from "red sprites". This finding is consistent with the production of diffuse optical emissions due to the heating of the lower ionosphere by electromagnetic pulses generated by lightning discharges.
Optical and search coil magnetometer data were obtained from the SPRITES'96 campaign carried out at Yucca Ridge Field Station, Colorado in July 1996. We have presented clear evidence for the excitation of ULF transients with their dominant power at 1-2 Hz by strong lightning discharges producing elves and sprites without preceding elves and the case of sprites with preceding elves. In the former case, damped quasi-sinusoidal oscillations commence impulsively at the onset of sprites, while in the latter case quasi-sinusoidal wavelets with a duration of 〜3 s are excited, and elves and sprites occur within each wavelet. It is lucky that these ULF transients are due to the nonlinear excitation of the ionospheric Alfven resonator by strong lightning discharge.

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Authorship：Coinvestigator(s) 

NO_x (NO+NO_2) plays a critical role on the phtochemical ozone (03) production in the troposhere. In this study, a prototype system for NO_2 detection has been developed for a future application on the aircraft measurement.
The UV Photolysis system to convert NO_2 into NO is the key of the instrument, beause the NO detection system has been already developed. We have used a metal halogen lamp as a light source. We have also used a photolysis cell of which wall was coated with reflective aluminum to increase the photolysis rate in the cell. We have also developed a Teflon valve to control a pressure inside the photolysis cell. As a result, a conversion efficiency of about 50% was obtained with a residence time inside of the cell of 1-2 sec. A conversion efficiency can be higher when pressure inside the cell is kept higher, however other molecules such as N_2O_5 was found to also be photodissociated. In addition, Uv in the wavelength shorter than 320nm should be cut using optical filter to prevent the photodissociation of HNO_3. Based on these results, we plan to develop a NO_2 detection system which can be used on board the aircraft.

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Authorship：Coinvestigator(s) 

In order to clarify the conjugacy of electromagnetic disturbances at auroral latitudes, and transfer (propagation) proceses of these disturbances from higher to equatorial latitudes, and to understand global variations of the magnetospheric phenomena, we had carried out the magnetic conjugate observations in Alaska and Macquarie Island. In this year we did the following overseas field research and collaborative study :
(1) We continued to observe auroral substorms at Kotzebue in Alaska by means of magnetometer, atmospheric electric field instrument, all-sky TV camera, and photometer.
Magnetic ad optical observations at the magnetic conjugate points of Kotzebue, i.e.Macquarie Island, were also carried out in cooperation with Australian Antarctic Division.
(3)Auroral observations at Tixie in Siberia, and in Canada were done in cooperations with IKFIA of Russian Academy of Science and GRL,Univ.of Tokyo. All-sky TV camera was installed at Zhigansk in Yakutsk to investigate the longitudinal expansion of auroral substorm.
(4) Magnetic observation at Koror near the magnetic equator was continued to study the relationships between eastward auroral electrojet and equatorial electrojet in daytime.
(5) Imaging Riometer observation was also continued to study the daytime aurora in the cusp region.
(6) The principal investigator visited Institute of Earth Physics, Russian Academy of Science, to start the collaborative data analysis, to summarize the results from this project, and to present the papers in future.
From these collaborative studies, the following results were obtained.
[I] Variations in the 10-min.to 1-hr period range of the eastward auroral electrojet are found to be identified in those of the dayside equatorial electrojet. The eastward auroral and equatorial electrojets may be connected by DP-type ionospheric currents.
[II] North/south hemisphere asymmetry of sc/si disturbances appears at low latitudes. The amplitude ranges at low-latitude conjugate points in the summer hemisphere are about twice as wide as those in the winter hemisphere. This can be interpreted by invoking an asymmetry in ionospheric currents driven by the DP field, i.e invoking enhanced ionospheric conductivities in the summer hemisphere.
[III] Field-line oscillations in the Pc3-5 range observed at the high and low-latitude conjugate pairs are found to show the northern/southern asymmetry and seasonal variations of amplitudes. These observational facts can not explained by using the existing theories.
These results give a clue to the unresolved propagation (transfer) mechanisms of electromagnetic disturbances from high latitude to the equatorial latitude.

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Authorship：Coinvestigator(s) 

In order to study precision dynamics of auroal disturbance, observation campaigns were carried out with network of all-sky TV cameras mainly in northern Canada and also in Greenland andin Svalbard for selected new moon periods of each winter during an international collaboration study period of Solar Terrestrial Energy Program (1991-1995, lately extended till 1997). CCD cameras with image-intensifier were operated at six to eight sites specifically in focus to the polar cap region in collaboration with participants from regional countries. On selected auroral spectral lines luminosity distribution along the meridian or monochromatic imaging for all-sky field of view were also observed at several key sites.
Two dimensional extent of magnetic field disturbances were continuously observed though the STEP period with a combination system of fluxgate and induction magnetometers at 20 sites and at eight more sitesonly induction magnetometers were operated. Data list and summary plots of acquired data are accessible in the home page of "STEP Polar Network" from the Internet by "http : //hpgrl. grl. s. u-tokyo. ac. jp/".
Some achievements and results from the observation are ;
1. Quasi-periodic poleward motions of sun-aligned auroral arcs in the morning side polar cap are found predominant during periods of northward interplanetary magnetic field.
2. High time resolution video data in the polar cap region indicates that auroal dynamics in the polar cap requires to be classified with a new framework including the rapid motion.
3. Conjunction studies between the ground based network observation with high time resolution both for magnetic field and auroral imaging are effectively going on in combination with each other and will be more promising in the coming maximum years of satellite missions for the magnetospheric studies.

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Authorship：Coinvestigator(s) 

In order to understand the global magnetospheric responses to solar wind changes and to investigate the transfer or propagation processes and latitudinal structures of magnetospheric disturbanoes, coordinated ground-based observations along the 210 degree magnetic meridian (MM) are being conducted in cooperation with 24 international and 4 national organizations. The results obtained from the 210 degree MM project are outlined as follows ; (1) a northern and southern hemisphere asymmetry for sudden commencements (SC) and sudden impulses (Si), due to DP-electric fields penetrating to the low-latitude ionosphere. (2) low-latitude auroras, occurring with invisible intensity in association with bay-type variation of H and D magnetic components and also large amplitude Pi magnetic pulsations, 3) cavity-like and field line Pc3-4 resonances stimulated by sc and si, (4) peculiarities of Pc 3 at low latitudes, such as larger amplitude decrease less than L=1,5, and longer period at lower latitudes towards the equator, due to the limitation of theoretical hypothesis of the thin ionosphere model and the mass loading effects of the field line oscillation, 5) latitudinal profile of Pi2, such as similarity in occurrence and amplitude less than 50 degree magnetic latitude, and phase reversal at the plasmapause latitude and the magnetic equator, and (6) intensity increase of LF whistler-mode signals and penetrating energetic electrons associated with magnetic disturbances.
On the other hand, longitudinally coordinated observations along the magnetic equator region are also being carried out, in order to elucidate the mechanisms of equatorial phenomena such as equatorial electro-jet currents and anomalous geomagnetic pulsation activities. The obtained data are being analyzed, and the initial results are in the followings ; (1) data acquisition at multiple observation sites in the magnetic equator region in Brazil and Peru, (2) simultaneous measurement of geomagnetic activities with ionospheric activities by FMCW radar, (3) amplitude range of 0.1-1.0 nT of equatorial magnetic pulsations, (4) spatial structures of equatorial electro-jet currents and relation between counter electro-jet currents and ionospheric electric fields.

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Authorship：Principal investigator 

Grant amount：\800000 （ Direct Cost: \800000 ）

平成5年度における低緯度オーロラ研究の実績は以下の通り
1.平成5年4月より北海道足寄郡陸別町において、分光測光器による低緯度オーロラの定常観測を開始した。また平成5年9月に、名古屋大学太陽地球環境研究所付属の北海道母子里観測所にある掃天分光測光器のメンテナンスを行った。両者は現在(平成6年3月)に至るまで定常観測を続けている。これらの定常観測から、平成5年9月13日の磁気嵐時に、陸別町において低緯度オーロラ観測に成功した。この観測は、通常の大きさの磁気嵐においても低緯度オーロラが発生するという平成4年度の発見を裏付ける重要な結果となった(平成5年9月13日の低緯度オーロラ観測については、現在論文として執筆中)。
2.平成4年5月10日の低緯度オーロラについて、EXOS-D衛星で同時に得られた電場データの解析から、この低緯度オーロラの発生直前には、磁気緯度50度以下の低緯度まで、磁気圏対流電場が侵入していたことが分かった。このことは磁気圏サブストームにともなった低緯度オーロラの発生メカニズムを知る上で、非常に重要な観測事実である。
3.平成4年に観測された4例の低緯度オーロラについて、オーロラの出現にともなって電離層に局所的な渦電流が発生し、さらにそれが時間とともに経度方向に移動していく構造が、地上多点磁場データの解析から新たに発見された。

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Authorship：Coinvestigator(s) 

1. Global structure of the distant tail GEOTAIL observations have confirmed that the magnetotail extends to 200 Re and beyond. It flaps violently north-south as well as east-west with amplitudes comparable to its average radius of about 20 Re, but there is no indication that it is filamentary. Plasma sheet is clearly distinguishable from the lobe or the magnetosheath by high temperature (around 1 keV) and low density (around 0.1/cc). Its magnetic structure and internal convection profile are governed by the north-south polarity of the interplanetary magnetic field.
2. Distant tail under the southward IMF Under the southward IMF,magnetic field lines convect toward the neutral sheet where they are reconnected. The probability that open field lines are reconnected earthward of 150 Re is about 75%. The reconnection rate is the highest at the tail axis and decreases toward the flanks by a factor of 2 to 3.
3. Plasma heating and relaxation at the plasma-sheet lobe boundary At the plasma sheet boundary, the slow-mode shock is formed in the convective flow where the cold ions of the lobe become heated. Very energetic ions flow upstream from the shock. The mixed population of cold and hot particles in this boundary region is a rich source of plasma waves whose non-linear development is seen.
4. Distant tail under northward IMF Under the northward IMF,the open field lines which are presumably produced in the cusp region of the dayside magnetopause sweep across the tail. The convection is parallel to the neutral sheet which is highly twisted in the direction of IMF and has opposite directions (dawn to dusk vs dusk to dawn) on opposite sides of the neutral sheet. The source of the hot plasma in the plasma sheet which is located in the open field lines poses a new problem.

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Authorship：Coinvestigator(s) 

In order to clarify the energy transfer processes of substorm-associated magnetic disturbances from higher to equatorial latitudes, and to understand global changes of the magnetospheric phenomena, we had carried out the magnetic and atmospheric electric fields, and aurora observations in Alaska and Siberia. In this year we did the following overseas field research : (1) We had installed a fluxgate magnetometer at Paratunk in Kamchtsuka, where low-latitude aurora sometimes appear.
(2) A co-investigator visited several institutes of Russian Academy of Science in Moscow to collect the solar and IMF data which are key parameters, controlling the occurrence of auroral substorms.
(3) Temporal observations of magnetic and atmospheric electric field were done in Argentina to check the electromagnetic environment variations.
(4) In Alaska, we also installed a fluxgate magnetometer at Kotzebue to detect auroral magnetic variations.
(5) All-sky TV camera and fluxgate magnetometer were shipped to IKFIA of Russian Academy of Science, Yakutsk, in order to observe auroral variations.
(6) Co-investigators in the University of Alaska were invited to the STE Lab., Nagoya University, and started the collaborative data analysis and studies on the auroral disturbances, the relationship between higher and lower latitude phenomena.
From these collaborative studies, the following results were obtained. [I] There are two generation mechanisms of low-latitude substorm-associated variations ; One is caused by an oscillation of field-aligned current intensity formed at high latitudes, and the other is a cavity-like oscillation excited in the inner magnetosphere.
[II] The low-latitude aurora must be excited during a substorm in the main phase of storm, when the substorm-associated electric field could accelerate hot-ring current proton into the inner magnetosphere. An interaction between the hot plasma and cold plasma in the plasmasphere must produce field-aligned electron precipitation and an upward FAC at lower latitudes with ionospheric equivalent vortex structure.

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Authorship：Coinvestigator(s) 

Campaign and network observations for aurora and magnetic field disturbances were carried out and deployed in the polar region, mainly Canada with some extension to Greenland, Spitzbergen and Norway, specifically focused to the global nature and dynamics linked with the magnetospheric processes. The magnetometer network was established at 17 sites with a combined system of fluxgate-induction magnetometers and at 8 site with an induction magnetometer through twice of field work in the summer of 1991 and 1992. Among the magnetometer sites producing important and interesting data, Eureka is specialized by its location close within one degree to the geomagnetic north pole. In December 1992 and January 1993 seven ultra-high sensitive TV cameras were set in the polar cap, cleft and auroral zone to recorded dynamic features of global auroral pattern in high time resolution. The auroral campaign was coordinated with the another campaign with similar TV systems at four sites conducted by University of Saskatchewan and with CANOPUS program of aurora and magnetic field by NRC. Three satellites, Geotail, Akebono and Freja, Were good location for conjunction study with possibilities to be caught at the foot prints of magnetic lines of force within the range of field of view of the TV camera nework.

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Authorship：Coinvestigator(s) 

The solar wind interacts with the earth's magnetic fields, and creates the bow shock, magnetosheath, magnetopause, boundary layer, various complicated structure in the magnetosphere, and. many kinds of magnetospheric disturbances. In order to study the electromagnetic and particle environment variations caused by the solar wind changes and the transfer processes of energy, momentum and mass from the solar wind into the magnetosphere and ionosphere, globally coordinated observations and data analysis were carried out in this project. All-sky TV-camera, four channel meridian scanning photometers, and high-sensitive monochromatic all-sky TV camera were installed at cusp, high, and low latitudes to investigate global auroral dynamics. Imaging (2-dimensional multi-beam) riometer was also installed in the polar cap to understand the characteristics of movement and spatial formation of auroral absorption during the substorm. Simultaneous magnetic observations along the 2100 magnetic meridian were carried out to get unique information on ULF wave energy transfer process from high latitude to the 6, quatorial region. In order to elucidate propagation mechanis of LF/VLF wa#es, Japan-Australia conjugate observations of LF/VLF transmission signals were also carried out. The following results are newly obtained.
(1) Low-latitude aurora can be detected at low latitude of L=1.6 during a usual magnetic storm, indicating that particle acceleration process occurs in the deep inner magnetosphere frequently.
(2) The solar wind ULF wave energy easily couples into a field-line oscillation around L=1.6, where may be associated with the plasma wave turbulence disc observed by EXOS-D satellite in the deep inner magnetosphere.
(3) The conjugate measurements of LF/VLF waves suggest the penetration of storm-related energetic electrons and magnetospheric electric fields into the low-L shell below 2.
These results evidence the energy, mass penetrations into the deep inner region.

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