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

• Project/Area Number: 18H03727
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Medium-sized Section 17:Earth and planetary science and related fields
• 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
• Project Status: Granted (Fiscal Year 2021)
• Budget Amount: ¥43,940,000 (Direct Cost: ¥33,800,000、Indirect Cost: ¥10,140,000); Fiscal Year 2021: ¥5,460,000 (Direct Cost: ¥4,200,000、Indirect Cost: ¥1,260,000); Fiscal Year 2020: ¥8,970,000 (Direct Cost: ¥6,900,000、Indirect Cost: ¥2,070,000); Fiscal Year 2019: ¥8,970,000 (Direct Cost: ¥6,900,000、Indirect Cost: ¥2,070,000); Fiscal Year 2018: ¥15,080,000 (Direct Cost: ¥11,600,000、Indirect Cost: ¥3,480,000)
• 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。
2018年度は課題【１】に関して、あらせ衛星により計測されたプラズマ波動電磁界データの較正手法についての検討を行ない、WPIA解析において重要となる「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整理した。波形較正手法に関する検討結果は課題【３】にも関わる重要な成果となった。解析研究としては、特に、電磁イオンサイクトロトン波動を対象としたWPIA手法をMMS衛星による観測結果に適用して、Science誌に報告した。また、あらせ衛星による観測結果の解析により、地球内部磁気圏で生じるプラズマ波動と高エネルギー電子との相互作用についての事例解析研究を行い、その成果を学術誌に公表した。課題【２】に関して、ホイッスラーモード・コーラス放射の発生過程に関する再現実験を大規模計算機シミュレーションにより実施して、高エネルギー電子の速度分布がコーラス放射の発生条件に対して及ぼす影響を定量的に明らかとした。以上成果は5編の学術論文ならびに招待講演7件を含む14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] University of Texas at Dallas(米国)
• [Journal Article] Visualization of rapid electron precipitation via chorus element wave?particle interactions (2019)
  • Author(s): Ozaki M. et al.
  • Journal Title: Nature Comm. Volume: 10 Pages: 1-9
  • DOI: 10.1038/s41467-018-07996-z
  • NAID: 120006550406
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Microscopic Observations of Pulsating Aurora Associated With Chorus Element Structures: Coordinated Arase Satellite‐PWING Observations (2018)
  • Author(s): Ozaki M. et al.
  • Journal Title: Geophys. Res. Lett. Volume: 45 Pages: 1-10
  • DOI: 10.1029/2018gl079812
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Electrostatic Electron Cyclotron Harmonic Waves as a Candidate to Cause Pulsating Auroras (2018)
  • Author(s): Fukizawa M.、Sakanoi T.、Miyoshi Y.、Hosokawa K.、Shiokawa K.、Katoh Y.、Kazama Y.、Kumamoto A.、Tsuchiya F.、Miyashita Y.、Tanaka Y. ‐M.、Kasahara Y.、Ozaki M.、Matsuoka A.、Matsuda S.、Hikishima M.、Oyama S.、Ogawa Y.、Kurita S.、Fujii R.
  • Journal Title: Geophys. Res. Lett. Volume: 45
  • DOI: 10.1029/2018gl080145
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Temporal and Spatial Correspondence of Pc1/EMIC Waves and Relativistic Electron Precipitations Observed With Ground-Based Multi-Instruments on 27 March 2017 (2018)
  • Author(s): Hirai A.、Tsuchiya F.、Obara T.、Kasaba Y.、Katoh Y.、Misawa H.、Shiokawa K.、Miyoshi Y.、Kurita S.、Matsuda S.、Connors M.、Nagatsuma T.、Sakaguchi K.、Kasahara Y.、Kumamoto A.、Matsuoka A.、Shoji M.、Shinohara I.、Albert J. M.
  • Journal Title: Geophys. Res. Lett. Volume: 45
  • DOI: 10.1029/2018gl080126
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Direct measurements of two-way wave-particle energy transfer in a collisionless space plasma (2018)
  • Author(s): Kitamura N.、Kitahara M.、Shoji M.、Miyoshi Y.、Hasegawa H.、Nakamura S.、Katoh Y.、Saito Y.、Yokota S.、Gershman D. J.、Vinas A. F.、Giles B. L.、Moore T. E.、Paterson W. R.、Pollock C. J.、Russell C. T.、Strangeway R. J.、Fuselier S. A.、Burch J. L.
  • Journal Title: Science Volume: 361 Pages: 1000-1003
  • DOI: 10.1126/science.aap8730
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] Simulation study of the whistler-mode chorus generation in the Earth's inner magnetosphere (2019)
  • Author(s): Katoh, Y. and Y. Omura
  • Organizer: URSI AP-RASC 2019
  • Int'l Joint Research
• [Presentation] Periodicity and spatial scale of wave-particle interactions in the magnetosphere (2018)
  • Author(s): Katoh, Y.
  • Organizer: ISSI Workshop “Auroral Physics”
  • Int'l Joint Research / Invited
• [Presentation] Electron hybrid simulations of the nonlinear processes of whistler-mode chorus generation in the Earth's inner magnetosphere (2018)
  • Author(s): Katoh, Y., Y. Omura, Y. Miyake, H. Usui, and H. Nakashima
  • Organizer: ISSS-13
  • Int'l Joint Research / Invited
• [Presentation] Nonlinear processes of whistler-mode chorus generation in the Earth's inner magnetosphere (2018)
  • Author(s): Katoh, Y., Y. Omura, Y. Miyake, H. Usui, and H. Nakashima
  • Organizer: American Geophysical Union Fall Meeting 2018
  • Int'l Joint Research / Invited
• [Presentation] Study of the modulation of whistler-mode chorus generation by ULF waves (2018)
  • Author(s): Katoh, Y. and L. Chen
  • Organizer: Asia Oceania Geosciences Society (AOGS) 15th Annual Meeting
  • Int'l Joint Research
• [Presentation] Simulation study of the dependence of the whistler-mode chorus generation on properties of energetic electrons in the Earth's inner magnetosphere (2018)
  • Author(s): Katoh, Y., Y. Omura, Y. Miyake, H. Usui, and H. Nakashima
  • Organizer: 日本地球惑星科学連合2018年大会
• [Presentation] Cross-reference simulations by scalable communication library for the study of wave-particle interactions in magnetospheres (2018)
  • Author(s): 加藤雄人, 深沢圭一郎, 南里豪志
  • Organizer: 第144回地球電磁気・地球惑星圏学会講演会
• [Presentation] Strong diffusion of hot electrons powering diffuse aurora (2018)
  • Author(s): Kasahara, S., Y. Miyoshi, S. Yokota, Y. Kasahara, S. Matsuda, A. Kumamoto, A. Matsuoka, H. U. Frey, V. Angelopoulos, S. Kurita, K. Keika, T. Hori, I. Shinohara
  • Organizer: American Geophysical Union Fall Meeting 2018
  • Int'l Joint Research
• [Presentation] Calibration of the medium-energy electron/ion analysers onboard ERG (Arase) (2018)
  • Author(s): Kasahara, S., S. Yokota, T. Mitani, K. Asamura, Y. Kazama, S-Y. Wang, K. Keika, T. Hori, T-F.Chang, Y. Miyoshi, and I. Shinohara
  • Organizer: CAA cross-calibration and Cluster SOWG
  • Int'l Joint Research
• [Presentation] In-situ observations of wave-particle interaction by ERG (Arase) (2018)
  • Author(s): Kasahara, S., Y. Miyoshi, I. Shinohara, K. Asamura, N. Higashio, Y. Kasahara, Y. Kazama, H. Kojima, A. Matsuoka, T. Mitani, S.-Y., Wang, and S. Yokota
  • Organizer: Magnetic Reconnection in Space, Solar, Astrophysical, and Laboratory Plasmas 2018
  • Int'l Joint Research / Invited
• [Presentation] Arase (ERG) Observation of Energetic Electrons in the Inner Magnetosphere and Roles of Waves (2018)
  • 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, K. Asamura, M. Hirahara, T. Takashima
  • Organizer: Asia Oceania Geosciences Society (AOGS) 15th Annual Meeting
  • Int'l Joint Research / Invited
• [Presentation] Arase (ERG) Observation of Electron Scattering by Chorus Waves near the Magnetospheric Equator (2018)
  • 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: URSI Atlantic Radio Science meeting 2018
  • Int'l Joint Research / Invited
• [Presentation] Strong diffusion of energetic electrons into diffuse aurora (2018)
  • Author(s): Kasahara, S., Y. Miyoshi, S. Yokota, Y. Kasahara, S. Matsuda, A. Kumamoto, A. Matsuoka, H. U. Frey, V. Angelopoulos, S. Kurita, K. Keika, T. Hori, I. Shinohara
  • Organizer: 第144回地球電磁気・地球惑星圏学会講演会
• [Presentation] Electron scattering by chorus waves generating pulsating aurora (2018)
  • 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: 日本地球惑星科学連合2018年大会
  • Invited