Evaluation of the formation mechanism of planetary radiation belts by direct measurement of particle acceleration processes

2019 Fiscal Year Annual Research Report

• Project/Area Number: 18H03727
• Research Institution: Tohoku University
• Principal Investigator: 加藤 雄人 東北大学, 理学研究科, 教授 (60378982)
• Co-Investigator(Kenkyū-buntansha): 笠原 慧 東京大学, 大学院理学系研究科(理学部), 准教授 (00550500)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: 宇宙プラズマ・プラズマ波動 / 地球惑星磁気圏 / 太陽地球システム・宇宙天気 / オーロラ・磁気嵐

Outline of Annual Research Achievements

本研究は、磁化天体に普遍的な高エネルギー粒子加速機構を解明することを最終目的として、宇宙空間で生じる電磁波と粒子との間のエネルギー交換過程について究明した。目的を達成するために本研究では、【１】あらせ衛星を中心とした地球磁気圏・放射線帯領域での衛星観測データを用いた解析研究、【２】大規模計算機実験による惑星電磁圏での波動・粒子間の共鳴過程の究明、【３】WPIA機上ソフトウェアの最適化とWPIA手法の確立、をそれぞれ実施した。
2019年度は課題【１】に関して、あらせ衛星による観測結果の解析により、ホイッスラーモード・コーラス放射と数keV-数十keVのエネルギー帯の電子との共鳴現象を捉えたイベントの事例解析ならびに統計解析を実施した。特に、ピッチ角散乱により大気へ降下する電子とコーラス放射の波動強度との対応に高い相関が見られること、コーラス放射の波動強度ががPc-5帯のULF波動と同期して増幅するイベントが見出され、数十keV帯の電子の温度異方性ならびにフラックスがULF波動によって大きな変調を受けることにより生じていることなどを明らかとした。課題【２】に関して、コヒーレントなホイッスラーモード波動による低ピッチ角電子の共鳴現象に関する計算機シミュレーションを実施して、ピッチ角の小さい電子に対して生じる特異な非線形過程の存在を見出し、ピッチ角が大きく変動する要因を理論的に明らかとした。課題【３】に関して、前年度までに検討した「位相の連続性」を保証するために最適なフィルタや波形処理フローを、WPIA処理に取り入れ、処理結果に及ぼされる影響を検討した。木星氷衛星探査ミッションJUICEにおけるS-WPIAでの解析フローについて、JUICE搭載機器の仕様に基づいた観測シーケンスを検討し確立した。以上成果は8編の学術論文ならびに招待講演7件を含む30件の国内外での学会・研究会での発表として公表した。

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

本研究で中心課題としている衛星データ解析研究、シミュレーション研究、WPIA手法の検討のそれぞれについて当初の計画通りに進められており、成果も既に上がっている。研究組織内での議論は円滑に進められており、当初の研究計画に対して順調に進展していると判断される。

Strategy for Future Research Activity

研究は順調に進展しており、次年度も当初の研究計画に従って研究を遂行する方針である。

Research Products

• [Int'l Joint Research] 宇宙科学研究所(スウェーデン)
  • Country Name: SWEDEN
  • Counterpart Institution: 宇宙科学研究所
• [Int'l Joint Research] テキサス大学ダラス校(米国)
  • Country Name: U.S.A.
  • Counterpart Institution: テキサス大学ダラス校
• [Int'l Joint Research] 台湾・国立中央大学(その他の国・地域)
  • Country Name: その他の国・地域
  • Counterpart Institution: 台湾・国立中央大学
• [Journal Article] Comprehensive Observations of Substorm‐Enhanced Plasmaspheric Hiss Generation, Propagation, and Dissipation (2020)
  • Author(s): Liu, N., Z. Su, Z. Gao, H. Zheng, Y. Wang, S. Wang, Y. Miyoshi, I. Shinohara, Y. Kasahara, et al.
  • Journal Title: Geophysical Research Letters Volume: 47 Pages: －
  • DOI: 10.1029/2019GL086040
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Anomalous Trapping of Low Pitch Angle Electrons by Coherent Whistler Mode Waves (2019)
  • Author(s): Kitahara M.、Katoh Y.
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 124 Pages: 5568～5583
  • DOI: 10.1029/2019JA026493
  • Peer Reviewed
• [Journal Article] A Systematic Study in Characteristics of Lower Band Rising‐Tone Chorus Elements (2019)
  • Author(s): Shue Jih‐Hong、Nariyuki Yasuhiro、Katoh Yuto、Saito Shinji、Kasahara Yoshiya、Hsieh Yi‐Kai、Matsuda Shoya、Goto Yoshitaka
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 124 Pages: 9003～9016
  • DOI: 10.1029/2019JA027368
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Strong Diffusion of Energetic Electrons by Equatorial Chorus Waves in the Midnight‐to‐Dawn Sector (2019)
  • Author(s): Kasahara S.、Miyoshi Y.、Kurita S.、Yokota S.、Keika K.、Hori T.、Kasahara Y.、Matsuda S.、Kumamoto A.、Matsuoka A.、Seki K.、Shinohara I.
  • Journal Title: Geophysical Research Letters Volume: 46 Pages: 12685～12692
  • DOI: 10.1029/2019GL085499
  • Peer Reviewed
• [Journal Article] Cusp and Nightside Auroral Sources of O + in the Plasma Sheet (2019)
  • Author(s): Kistler L. M.、Mouikis C. G.、Asamura K.、Yokota S.、Kasahara S.、Miyoshi Y.、Keika K.、Matsuoka A.、Shinohara I.、Hori T.、Kitamura N.、Petrinec S. M.、Cohen I. J.、Delcourt D. C.
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 124 Pages: 10036～10047
  • DOI: 10.1029/2019JA027061
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Statistical Properties of Molecular Ions in the Ring Current Observed by the Arase (ERG) Satellite (2019)
  • Author(s): Seki K.、Keika K.、Kasahara S.、Yokota S.、Hori T.、Asamura K.、Higashio N.、Takada M.、Ogawa Y.、Matsuoka A.、Teramoto M.、Miyoshi Y.、Shinohara I.
  • Journal Title: Geophysical Research Letters Volume: 46 Pages: 8643～8651
  • DOI: 10.1029/2019GL084163
  • Peer Reviewed
• [Journal Article] Meridional Distribution of Middle‐Energy Protons and Pressure‐Driven Currents in the Nightside Inner Magnetosphere: Arase Observations (2019)
  • Author(s): Imajo S.、Nose M.、Kasahara S.、Yokota S.、Matsuoka A.、Keika K.、Hori T.、Teramoto M.、Yamamoto K.、Oimatsu S.、Nomura R.、Fujimoto A.、Shinohara I.、Miyoshi Y.
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 124 Pages: 5719～5733
  • DOI: 10.1029/2019JA026682
  • Peer Reviewed
• [Journal Article] Acceleration of Ions in Jovian Plasmoids: Does Turbulence Play a Role? (2019)
  • Author(s): Kronberg E. A.、Grigorenko E. E.、Malykhin A.、Kozak L.、Petrenko B.、Vogt M. F.、Roussos E.、Kollmann P.、Jackman C. M.、Kasahara S.、Malova Kh. V.、Tao C.、Radioti A.、Masters A.
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 124 Pages: 5056～5069
  • DOI: 10.1029/2019JA026553
  • Peer Reviewed / Int'l Joint Research
• [Presentation] Cross-reference simulations by scalable communication library for the study of wave-particle interactions in planetary magnetospheres (2019)
  • Author(s): Katoh, Y., K. Fukazawa, T. Nanri, and Y. Miyake
  • Organizer: Asia Oceania Geosciences Society (AOGS) 16th Annual Meeting
  • Int'l Joint Research
• [Presentation] Theory and computer simulations on whistler-mode chorus emissions and related wave-particle interactions in planetary magnetospheres (2019)
  • Author(s): Katoh, Y.
  • Organizer: 2019 URSI-Japan Radio Science Meeting
  • Int'l Joint Research / Invited
• [Presentation] Simulation study of the whistler-mode chorus generation in the Earth's inner magnetosphere (2019)
  • Author(s): Katoh, Y. and Y. Omura
  • Organizer: 3rd Asia-Pacific Conference on Plasma Physics
  • Int'l Joint Research / Invited
• [Presentation] Modulation of the whistler-mode chorus generation by ULF waves in the inner magnetosphere (2019)
  • Author(s): Katoh, Y. and L. Chen
  • Organizer: American Geophysical Union 2019 Fall Meeting
  • Int'l Joint Research
• [Presentation] Cross-Reference Simulation by Code-To-Code Adapter (CoToCoA) Library for the Study of Planetary Magnetospheres (2019)
  • Author(s): Katoh, Y., K. Fukazawa, T. Nanri, Y. Miyake
  • Organizer: High Performance Computing in Asia-Pacific Region (HPC Asia 2020)
  • Int'l Joint Research
• [Presentation] Cross-reference simulations by scalable communication library for the study of wave-particle interactions in planetary magnetospheres (2019)
  • Author(s): Katoh, Y., K. Fukazawa, T. Nanri, and Y. Miyake
  • Organizer: 日本地球惑星科学連合2019年大会
• [Presentation] ULF wave modulation of the whistler-mode chorus generation in the inner magnetosphere (2019)
  • Author(s): Katoh, Y., L. Chen
  • Organizer: 第146回地球電磁気・地球惑星圏学会講演会
• [Presentation] Theory and simulation of anomalous trapping of low pitch angle electrons by whistler mode chorus emissions (2019)
  • Author(s): Kitahara, M. and Y. Katoh
  • Organizer: American Geophysical Union Fall Meeting 2019
  • Int'l Joint Research
• [Presentation] あらせ衛星搭載の PWE/WFC によって計測した波形データの較正手法の評価 (2019)
  • Author(s): 北原 理弘, 松田 昇也, 加藤 雄人, 笠原 禎也, 小嶋 浩嗣, 疋島 充
  • Organizer: 第146回地球電磁気・地球惑星圏学会講演会
• [Presentation] Arase 衛星 S-WPIA 解析におけるプラズマ波動及び粒子の較正に関する評価 (2019)
  • Author(s): 三木 淳平, 小嶋 浩嗣, 加藤 雄人, 松田 昇也, 笠原 禎也, 西澤 宏幸, 疋島 充, 栗田 怜, 北原 理弘, 笠原 慧, 三好 由純, 熊本 篤志, 松岡 彩子, 横田 勝一郎, 堀 智昭, 桂華 邦裕
  • Organizer: 第146回地球電磁気・地球惑星圏学会講演会
• [Presentation] Statistical study of EMIC wave-related electron precipitation at subauroral latitude (2019)
  • Author(s): Asuka Hirai, Fuminori Tsuchiya, Takahiro Obara, Yasumasa Kasaba, Yuto Katoh, Hiroaki Misawa, Kazuo Shiokawa, Yoshizumi Miyoshi, Satoshi Kurita, Martin Connors
  • Organizer: 第146回地球電磁気・地球惑星圏学会講演会
• [Presentation] Pc4-5 帯 ULF 波動とのドリフト共鳴による高エネルギー電子の変動とコーラス放射の強度変調について (2019)
  • Author(s): 大野 敦裕, 加藤 雄人, 寺本 万里子, 熊本 篤志, 土屋 史紀, 笠原 禎也, 松田 昇也, 松岡 彩子, 三谷 烈史, 堀 智昭, 笠原 慧, 横田 勝一郎, 桂華 邦裕, 三好 由純, 篠原 育
  • Organizer: 第146回地球電磁気・地球惑星圏学会講演会
• [Presentation] Elastic collisions between magnetospheric electrons and neutral H2O molecules in the Enceladus torus by test particle simulation (2019)
  • Author(s): Tadokoro, H., and Y. Katoh
  • Organizer: 第146回地球電磁気・地球惑星圏学会講演会
• [Presentation] Development of cross-reference framework for macro- and micro-scale simulations of the magnetosphere (2019)
  • Author(s): Keiichiro Fukazawa, Yuto Katoh, Takeshi Nanri, Yohei Miyake
  • Organizer: 第146回地球電磁気・地球惑星圏学会講演会
• [Presentation] Pitch angle scattering due to elastic collisions between magnetospheric 500eV-50keV electrons and neutral H2O originated from Enceladus: Test particle simulation (2019)
  • Author(s): Tadokoro, H. and Y. Katoh
  • Organizer: 日本地球惑星科学連合2019年大会
• [Presentation] Conjugated quasi-periodic ELF/VLF emissions between the Arase satellite and both Van Allen Probes (2019)
  • Author(s): Claudia Martinez Calderon, Frantisek Nemec, Kazuo Shiokawa, Yuto Katoh, Yoshiya Kasahara, Shoya Matsuda, Fuminori Tsuchiya, Atsushi Kumamoto, Mariko Teramoto, Ayako Matsuoka, Yoshizumi Miyoshi, Ondrej Santolik, George Hospodarksy
  • Organizer: 日本地球惑星科学連合2019年大会
• [Presentation] The Radio & Plasma Wave Investigation (RPWI) for JUICE for the investigation of Jupiter and Icy Moons System: Contributions from Japan (2019)
  • Author(s): Yasumasa Kasaba, Hiroaki Misawa, Fuminori Tsuchiya, Atsushi Kumamoto, Yuto Katoh, Tomoki Kimura, Hajime Kita, J.-E. Wahlund
  • Organizer: 日本地球惑星科学連合2019年大会
• [Presentation] Statistical study of IPDP type EMIC wave-related electron precipitation at subauroral latitude (2019)
  • Author(s): Asuka Hirai, Fuminori Tsuchiya, Takahiro Obara, Yasumasa Kasaba, Yuto Katoh, Hiroaki Misawa, Kazuo Shiokawa, Yoshizumi Miyoshi, Satoshi Kurita, Martin G Connors
  • Organizer: 日本地球惑星科学連合2019年大会
• [Presentation] Calibration of electric fields dedicated to the measurement of the S-WPIA of the Arase Satellite (2019)
  • Author(s): Miki Jumpei, Hirotsugu Kojima, Yuto Katoh, Shoya Matsuda, Yoshiya Kasahara, Mitsuru Hikishima, Satoshi Kurita, Masahiro Kitahara, Satoshi Kasahara, Yoshizumi Miyoshi, Atsushi Kumamoto, Ayako Matsuoka, Shoichiro Yokota, Tomoaki Hori, Kunihiro Keika
  • Organizer: 日本地球惑星科学連合2019年大会
• [Presentation] Enhancement of whistler-mode chorus in association with Pc 4-5 ULF waves and related variation of high energy electrons (2019)
  • Author(s): Atsuhiro Ono, Yuto Katoh, Atsushi Kumamoto, Fuminori Tsuchiya, Mariko Teramoto, Yoshiya Kasahara, Shoya Matsuda, Ayako Matsuoka, Takefumi Mitani, Tomoaki Hori, Satoshi Kasahara, Shoichiro Yokota, Kunihiro Keika, Yoshizumi Miyoshi, Iku Shinohara
  • Organizer: 日本地球惑星科学連合2019年大会
• [Presentation] Electron scattering by chorus waves as seen by ERG (2019)
  • Author(s): Kasahara, S., Y. Miyoshi, S. Kurita, S. Yokota, K. Keika, T. Hori, Y. Kasahara, S. Matsuda, A. Kumamoto, A. Matsuoka, K. Seki, T. Mitani, Y. Kazama, H. U. Frey, V. Angelopoulos, I. Shinohara
  • Organizer: ERG Science and Space Weather Workshop
  • Int'l Joint Research
• [Presentation] Pulsating aurora from electron scattering by chorus waves (2019)
  • Author(s): Kasahara, S., Y. Miyoshi, S. Kurita, S. Yokota, K. Keika, T. Hori, Y. Kasahara, S. Matsuda, A. Kumamoto, A. Matsuoka, K. Seki, T. Mitani, Y. Kazama, H. U. Frey, V. Angelopoulos, I. Shinohara
  • Organizer: American Geophysical Union Fall Meeting 2019
  • Int'l Joint Research / Invited
• [Presentation] Electron scattering by chorus waves as seen by ERG (2019)
  • Author(s): Kasahara, S., Y. Miyoshi, S. Kurita, S. Yokota, K. Keika, T. Hori, Y. Kasahara, S. Matsuda, A. Kumamoto, A. Matsuoka, K. Seki, T. Mitani, Y. Kazama, H. U. Frey, V. Angelopoulos, I. Shinohara
  • Organizer: ISEE-KASI workshop
  • Int'l Joint Research
• [Presentation] Medium-Energy Particle experiments (MEPs) onboard ERG (Arase) for substorm observations (2019)
  • Author(s): Kasahara, S., S. Yokota, T. Mitani, K. Asamura, M. Hirahara, T. Takashima, K. Keika, T. Hori, Y. Miyoshi, I. Shinohara
  • Organizer: International Conference on Substorm
  • Int'l Joint Research
• [Presentation] Electron Scattering by Chorus Waves Generating Pulsating Aurora (2019)
  • Author(s): Kasahara, S., Y. Miyoshi, S. Yokota, T. Mitani, Y. Kasahara, S. Matsuda, A. Kumamoto, A. Matsuoka, Y. Kazama, H. U. Frey, V. Angelopoulos, S. Kurita, K. Keika, K. Seki, I. Shinohara
  • Organizer: Asia Oceania Geosciences Society (AOGS) 16th Annual Meeting
  • Int'l Joint Research / Invited
• [Presentation] Pulsating aurora from electron scattering by chorus waves (2019)
  • Author(s): Kasahara, S., Y. Miyoshi, S. Yokota, T. Mitani, Y. Kasahara, S. Matsuda, A. Kumamoto, A. Matsuoka, Y. Kazama, H. U. Frey, V. Angelopoulos, S. Kurita, K. Keika, K. Seki, I. Shinohara
  • Organizer: Magnetospheres of Outer Planets
  • Int'l Joint Research / Invited
• [Presentation] Pulsating aurora from electron scattering by chorus waves (2019)
  • Author(s): Kasahara, S., Y. Miyoshi, S. Yokota, T. Mitani, Y. Kasahara, S. Matsuda, A. Kumamoto, A. Matsuoka, Y. Kazama, H. U. Frey, V. Angelopoulos, S. Kurita, K. Keika, K. Seki, I. Shinohara
  • Organizer: EGU General Assembly 2019
  • Int'l Joint Research / Invited
• [Presentation] Strong diffusion of energetic electrons by equatorial chorus waves in the midnight-dawnside magnetosphere (2019)
  • Author(s): Kasahara, S., Y. Miyoshi, S. Kurita, S. Yokota, K. Keika, T. Hori, Y. Kasahara, S. Matsuda, A. Kumamoto, A. Matsuoka, K. Seki, I. Shinohara
  • Organizer: 第146回地球電磁気・地球惑星圏学会講演会
• [Presentation] 放射線帯におけるWhistler chorus波動による電子のピッチ角散乱：strong diffusionの緯度分布 (2019)
  • Author(s): Kasahara, S., Y. Miyoshi, S. Kurita, S. Yokota, K. Keika, T. Hori, Y. Kasahara, S. Matsuda, A. Kumamoto, A. Matsuoka, K. Seki, I. Shinohara
  • Organizer: ERG衛星粒子観測データ解析ワークショップ
• [Presentation] Electron scattering by isolated chorus elements observed near the magnetospheric equator (2019)
  • Author(s): Kasahara, S., Y. Miyoshi, S. Yokota, Y. Kasahara, S. Matsuda, A. Matsuoka, K. Keika, T. Hori, and I. Shinohara
  • Organizer: 日本地球惑星科学連合2019年大会
  • Invited