Study of particle acceleration in Jupiter's magnetosphere by space and ground-based observations, and models

• Project/Area Number: 19H01948
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 17010:Space and planetary sciences-related
• Research Institution: The University of Tokyo
• Principal Investigator: Yoshioka Kazuo 東京大学, 大学院新領域創成科学研究科, 講師 (70637131)
• Co-Investigator(Kenkyū-buntansha): 山崎 敦 国立研究開発法人宇宙航空研究開発機構, 宇宙科学研究所, 助教 (00374893) ; 土屋 史紀 東北大学, 理学研究科, 准教授 (10302077) ; 木村 智樹 東京理科大学, 理学部第一部物理学科, 准教授 (50578804) ; 北 元 東北工業大学, 工学部, 講師 (60756493) ; 垰 千尋 国立研究開発法人情報通信研究機構, 電磁波研究所電磁波伝搬研究センター, 主任研究員 (80552562)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥16,900,000 (Direct Cost: ¥13,000,000、Indirect Cost: ¥3,900,000); Fiscal Year 2021: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2020: ¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000); Fiscal Year 2019: ¥7,540,000 (Direct Cost: ¥5,800,000、Indirect Cost: ¥1,740,000)
• Keywords: 木星磁気圏 / 粒子加速 / プラズマ / イオトーラス / 紫外線 / 宇宙望遠鏡 / イオ / ひさき衛星 / ハッブル宇宙望遠鏡 / 惑星磁気圏 / 探査機 / 木星 / 電離圏 / 流星 / 放射線帯 / 衛星火山 / スペクトル診断 / プラズマパラメタ / 電子温度

Outline of Research at the Start

先行研究と「ひさき」のこれまでの観測成果に基づき，我々は相対論的電子を生み出す木星の粒子加速に関して，衛星イオからの火山噴出物と太陽風等の外的要因に支配される物理仮説を提唱している．本研究では，木星磁気圏を支配する準定常的な粒子加速に対して，火山イベントなどの時間変動のある過程が及ぼす影響を「ひさき」，Juno，地上電波観測，数値モデルの４者連携により実証する．

Outline of Final Research Achievements

Through this research, we established a method for the spectral analysis of Jupiter's magnetosphere obtained by Hisaki satellite and developed a new theory to explain the plasma dynamics in the magnetosphere. Furthermore, we facilitated technical exchanges with international researchers through workshops, demonstrating the significance of Japan's planetary magnetosphere research. We also took the lead in coordinated observations with other observation satellites, including the Hubble Space Telescope, and multiple ground-based facilities, resulting in the publication of numerous papers in international academic journals. Additionally, based on the achievements and knowledge gained from this research, we advanced the consideration of the next-generation space telescope and were selected as an official candidate for JAXA's upcoming mission during the final year of the research period. It can be said that this research greatly contributed as a catalyst for these activities.

Academic Significance and Societal Importance of the Research Achievements

本科研費研究を通して惑星磁気圏に関する理解が向上したと言える．電離圏電流の変動やオーロラ発光の変動，放射線帯からの電波放射の強度変動，モデル計算などを総合的に解析することで，木星磁気圏におけるプラズマダイナミクスを一連の流れとしてとらえるための枠組みを構築できた．この成果は，地球とは規模や強度がけた違いに大きい木星磁気圏を理解することで，対比的に我々が住む地球の磁気圏環境を理解できるという点でも極めて重要である．さらに，惑星磁気圏研究界における日本の研究者コミュニティの存在感を示すことにもつながった．また，多くの修士論文，博士論文の執筆にも寄与できたことは，研究分野の活性化に繋がる成果である．

Research Products

• [Int'l Joint Research] Colorado University(米国)
• [Journal Article] Constraints on Europa's water group torus from HST/COS observations (2023)
  • Author(s): Lorenz Roth, H. Todd Smith, Kazuo Yoshioka, Tracy M. Becker, Aljona Blocker, Nathaniel J. Cunningham, Nickolay Ivchenko, Kurt D. Retherford, Joachim Saur, Michael Velez, Fuminori Tsuchiya
  • Journal Title: Earth and Planetary Astrophysics, Volume: in press
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Effect of Meteoric Ions on Ionospheric Conductance at Jupiter (2022)
  • Author(s): Nakamura Yuki、Terada Koichiro、Tao Chihiro、Terada Naoki、Kasaba Yasumasa、Leblanc Fran?ois、Kita Hajime、Nakamizo Aoi、Yoshikawa Akimasa、Ohtani Shinichi、Tsuchiya Fuminori、Kagitani Masato、Sakanoi Takeshi、Murakami Go、Yoshioka Kazuo、Kimura Tomoki、Yamazaki Atsushi、Yoshikawa Ichiro
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 127 Issue: 3
  • DOI: 10.1029/2022ja030312
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] . Long-term monitoring of energetic protons at the bottom of Earth’s radiation belt (2021)
  • Author(s): Yoshioka, K., Miyoshi, Y., Kurita, S., Teramoto, M., Tsuchiya, F., Yamazaki, A., Murakami, G., Kimura, T., Kita, H., Yoshikawa, I., and Kasaba, Y.
  • Journal Title: Space Weather Volume: 19 Issue: 1
  • DOI: 10.1029/2020sw002611
  • Peer Reviewed
• [Journal Article] Variation of Jupiter's Aurora Observed by Hisaki/EXCEED: 4. Quasi‐Periodic Variation (2021)
  • Author(s): Chihiro Tao , Tomoki Kimura , Elena A. Kronberg , Fuminori Tsuchiya , Go Murakami , Atsushi Yamazaki , Marissa F. Vogt , Bertrand Bonfond , Kazuo Yosihoka , Ichiro Yoshikawa , Yasumasa Kasaba , Hajime Kita , Shogo Okamoto
  • Journal Title: Journal of Geophysical Research, Space Physics Volume: 126 Issue: 2
  • DOI: 10.1029/2020ja028575
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Jovian UV Aurora's Response to the Solar Wind: Hisaki EXCEED and Juno Observations (2019)
  • Author(s): Kita H.、Kimura T.、Tao C.、Tsuchiya F.、Murakami G.、Yamazaki A.、Yoshioka K.、Ebert R.W.、Wilson R.J.、Allegrini F.、Clark G.、Connerney J. E. P.、Gladstone G. R.、Yoshikawa I.、Fujimoto M.
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 124 Issue: 12 Pages: 10209-10218
  • DOI: 10.1029/2019ja026997
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Transient Change of Io's Neutral Oxygen Cloud and Plasma Torus Observed by Hisaki (2019)
  • Author(s): Koga Ryoichi、Tsuchiya Fuminori、Kagitani Masato、Sakanoi Takeshi、Yoshioka Kazuo、Yoshikawa Ichiro、Kimura Tomoki、Murakami Go、Yamazaki Atsushi、Smith H. Todd、Bagenal Fran
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 124 Issue: 12 Pages: 10318-10331
  • DOI: 10.1029/2019ja026877
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] Temporal variation of the Io plasma torus seen from Hisaki satellite (2021)
  • Author(s): Yoshioka, K., F. Tsuchiya, M. Kagitani, F. Bagenal, N. Schneider, G. Murakami, T. Kimura, A. Yamazaki, H. Kita, E. Nerney, I. Yoshikawa, and R. Hikida
  • Organizer: Magnetosphere of Outer planets 2021
  • Int'l Joint Research
• [Presentation] The observational study for high energy particles below L=2.1 using Hisaki (2020)
  • Author(s): 吉岡和夫、吉川一朗、山崎敦，村上豪，木村智樹、北元，土屋史紀，三好由純，栗田怜，寺本万里子，吉川一朗
  • Organizer: 日本地球惑星科学連合
• [Presentation] The radial transport of plasmas around Jupiter’s inner magnetosphere with response to Io’s volcanic activity (2019)
  • Author(s): Yoshioka, K., F. Tsuchiya, M. Kagitani, T. Kimura, G. Murakami, D. Fukuyama, R. Hikida, F. Suzuki, A. Yamazaki, I. Yoshikawa, and M. Fujimoto
  • Organizer: AGU Fall meeting 2019
  • Int'l Joint Research
• [Presentation] The influence of Io’s volcanic activity in 2015 on Jupiter’s magnetospheric dynamics (2019)
  • Author(s): Yoshioka, K., F. Tsuchiya, M. Kagitani, T. Kimura, G. Murakami, D. Fukuyama, R. Hikida, F. Suzuki, A. Yamazaki, I. Yoshikawa, and M. Fujimot
  • Organizer: MOP meeting 2019
  • Int'l Joint Research