MAVEN observations of ion escape from Mars driven by magntic reconnection

• Project/Area Number: 19K14784
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 17010:Space and planetary sciences-related
• Research Institution: Kyoto University
• Principal Investigator: Harada Yuki 京都大学, 理学研究科, 助教 (90823386)
• Project Period (FY): 2019-02-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000); Fiscal Year 2020: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2019: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
• Keywords: 火星 / 磁気リコネクション / 大気散逸 / 地殻残留磁化 / 惑星プラズマ / 火星大気散逸 / 超高層物理学

Outline of Research at the Start

宇宙空間への大気散逸は、過去から現在への火星の気候変動において主要な役割を果たしたと考えられている。火星の大気が過去から現在にかけてどの程度失われたかを推定するには、複数ある大気散逸機構のそれぞれについて詳細な物理機構を理解することが重要である。本研究では、有力なイオン加速機構である磁気リコネクションに着目し、火星探査機MAVENの観測データの解析から、磁気リコネクションが火星イオン流出において果たす役割を解明する。

Outline of Final Research Achievements

In this study, we investigate the acceleration of planetary ions by magnetic reconnection and its contribution to ion escape from Mars by analyzing long-term data obtained by Martian orbiters. The results show that (i) magnetic reconnection can operate in many locations around Mars, (ii) transient reconnection frequently occurs above the Martian crustal magnetic fields, and (iii) instantaneous ion escape rates by reconnection jets could become comparable to those of other bulk escape mechanisms while the time-averaged escape rate would provide only a small contribution to the total ion escape rate.

Academic Significance and Societal Importance of the Research Achievements

過去研究では火星周辺空間における磁気再結合の発生条件や空間分布が不明であったが、本研究の結果を総合すると、火星圏は磁力線形状が常に時間変化し続けるダイナミックな電磁環境であることが示唆された。これは、近年広域撮像画像が取得可能になり急速に研究が発展している、火星ディスクリートオーロラ観測の結果が指し示す描像と合致する。本研究の結果から得られる知見は、今後進展が期待される火星圏多点観測や複数ミッション観測データの複合解析に応用できるという点で重要な成果である。

Research Products

• [Int'l Joint Research] アイオワ大学/NASAゴダード宇宙飛行センター/カリフォルニア大学バークレー校(米国)
• [Journal Article] Exploring the Solar Wind-Planetary Interaction at Mars: Implication for Magnetic Reconnection (2023)
  • Author(s): Bowers, C. F., DiBraccio, G. A., Slavin, J.A., Gruesbeck, J. R., Weber, T., Xu, S., Romanelli, N., Harada, Y.
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 128 Issue: 2
  • DOI: 10.1029/2022ja030989
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] A statistical investigation of factors influencing the magnetotail twist at Mars (2022)
  • Author(s): DiBraccio, G. A., N. Romanelli, C. Bowers, J. R. Gruesbeck, J. S. Halekas, S. Ruhunisiri, T. Weber, J. R. Espley, S. Xu, J. G. Luhmann, Y. Harada, E. Dubinin, G. K. Poh, J. E. P. Connerney, D. A. Brain, and S. M. Curry
  • Journal Title: Geophysical Research Letters Volume: 49 Issue: 12
  • DOI: 10.1029/2022gl098007
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Martian Ionospheric Magnetic Fluctuations below 200 km (2022)
  • Author(s): Esman, T. M., J. Espley, J. Gruesbeck, C. M. Fowler, S. Xu, M. Elrod, Y. Harada, J. Giacalone
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 127 Issue: 9
  • DOI: 10.1029/2022ja030470
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] A Comparative Study of Magnetic Flux Ropes in the Nightside Induced Magnetosphere of Mars and Venus (2022)
  • Author(s): Hara Takuya、Huang Zesen、Mitchell David L.、DiBraccio Gina A.、Brain David A.、Harada Yuki、Luhmann Janet G.
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 127 Issue: 1
  • DOI: 10.1029/2021ja029867
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] The Mars system revealed by the Martian Moons eXploration mission (2022)
  • Author(s): Ogohara Kazunori、Nakagawa Hiromu、Aoki Shohei et al.
  • Journal Title: Earth, Planets and Space Volume: 74 Issue: 1 Pages: 1-1
  • DOI: 10.1186/s40623-021-01417-0
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] In situ observations of ions and magnetic field around Phobos: the mass spectrum analyzer (MSA) for the Martian Moons eXploration (MMX) mission (2021)
  • Author(s): Yokota Shoichiro、Terada Naoki、Matsuoka Ayako、Murata Naofumi、Saito Yoshifumi、Delcourt Dominique、Futaana Yoshifumi、Seki Kanako、Schaible Micah J.、Asamura Kazushi、Kasahara Satoshi、Nakagawa Hiromu、Nishino Masaki N.、Nomura Reiko、Keika Kunihiro、Harada Yuki、Imajo Shun
  • Journal Title: Earth, Planets and Space Volume: 73 Issue: 1 Pages: 216-216
  • DOI: 10.1186/s40623-021-01452-x
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Ion Jets Within Current Sheets in the Martian Magnetosphere (2020)
  • Author(s): Harada Y.、Halekas J. S.、Xu S.、DiBraccio G. A.、Ruhunusiri S.、Hara T.、Mcfadden J. P.、Espley J. R.、Mitchell D. L.、Mazelle C.
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 125 Issue: 12
  • DOI: 10.1029/2020ja028576
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Locally generated ULF waves in the Martian magnetosphere: MAVEN observations (2019)
  • Author(s): Harada, Y, S. Ruhunusiri, J. S. Halekas, J. Espley, G. A. DiBraccio, J. P. McFadden, D. L. Mitchell, C. Mazelle, G. Collinson, D. A. Brain, T. Hara, M. Nose, S. Oimatsu, K. Yamamoto, and B. M. Jakosky
  • Journal Title: J. Geophys. Res. Volume: 124 Issue: 11 Pages: 1-20
  • DOI: 10.1029/2019ja027312
  • Peer Reviewed / Int'l Joint Research
• [Presentation] SEPイベント時の火星夜側電離圏におけるレーダー電波吸収についての観測・シミュレーション比較 (2023)
  • Author(s): 原田裕己
  • Organizer: 第24回惑星圏研究会
• [Presentation] MAVENとMEXの準同時多地点観測による上流プロトンサイクロトロン波動が火星電離圏にULF波動を駆動する確率の推定 (2023)
  • Author(s): 今田馨
  • Organizer: 第24回惑星圏研究会
• [Presentation] Mars Express・MAVEN探査機の遠隔・直接同時観測による火星電離圏電子密度擾乱の研究 (2023)
  • Author(s): 坂東日菜
  • Organizer: 第24回惑星圏研究会
• [Presentation] レーダーサウンディング観測とその場観測による火星電離圏不規則構造の駆動源の研究 (2022)
  • Author(s): 坂東日菜
  • Organizer: 日本地球惑星科学連合2022年大会
• [Presentation] MAVEN and MEX Quasi-Simultaneous Multipoint Observations of Solar Wind-Driven Waves in the Ionosphere of Mars (2022)
  • Author(s): 今田馨
  • Organizer: 日本地球惑星科学連合2022年大会
• [Presentation] Simultaneous Remote and In-situ Observations of Irregularities in the Martian Ionosphere: Origins of Diffuse Echoes on Ionograms (2022)
  • Author(s): 坂東日菜
  • Organizer: AOGS 18th Annual Meeting
  • Int'l Joint Research
• [Presentation] MAVEN衛星による火星プラズマダイナミクスの観測と今後の展望 (2022)
  • Author(s): 原田裕己
  • Organizer: 地球電磁気・地球惑星圏学会第152回講演会
  • Invited
• [Presentation] MAVENおよびMEXによる太陽風が駆動するULF波動の火星電離圏への伝搬の準同時多地点観測 (2022)
  • Author(s): 今田馨
  • Organizer: 地球電磁気・地球惑星圏学会第152回講演会
• [Presentation] Simultaneous observations of ionospheric irregularities at Mars by Mars Express MARSIS topside sounder and MAVEN (2022)
  • Author(s): 坂東日菜
  • Organizer: 地球電磁気・地球惑星圏学会第152回講演会
• [Presentation] 火星電離圏不規則構造の遠隔・直接同時観測 (2022)
  • Author(s): 坂東日菜, 原田裕己, 寺田直樹, 中川広務
  • Organizer: 第23回惑星圏研究会
• [Presentation] Oxygen ion modulation by magnetosonic waves in the upper ionosphere of Mars (2021)
  • Author(s): 原田裕己, C. M. Fowler, G. Collinson, J. S. Halekas, S. Ruhunusiri, G. A. DiBraccio, J. P. McFadden, T. Hara, J. Espley, D. L. Mitchell, C. Mazelle
  • Organizer: 第150回SGEPSS総会および講演会
• [Presentation] Reconnection Jets Observed by MAVEN Around Mars: Implications for Ion Escape (2021)
  • Author(s): Harada, Y., J. S. Halekas, S. Xu, G. A. DiBraccio, S. Ruhunusiri, T. Hara, J. P. McFadden, J. Espley, D. L. Mitchell, C. Mazelle
  • Organizer: AOGS 18th Annual Meeting
  • Int'l Joint Research
• [Presentation] MAVENおよびMGS観測データを用いた火星地殻残留磁場近傍での周期的電子注入現象の研究 (2021)
  • Author(s): 加藤倫生, 原田裕己, David L. Mitchell, Christian Mazelle, Gina A. DiBraccio, Jasper S. Halekas, Suranga Ruhunusiri
  • Organizer: 日本地球惑星科学連合2021年大会
• [Presentation] 火星電離圏不規則構造の遠隔・直接同時観測 (2021)
  • Author(s): 坂東日菜, 原田裕己, 寺田直樹, 中川広務
  • Organizer: 日本地球惑星科学連合2021年大会
• [Presentation] MAVEN および MGS 観測データを用いた火星地殻残留磁化近傍での周期的電子注入現象の発生機構についての研究 (2021)
  • Author(s): 加藤倫生, 原田裕己, David L. Mitchell, Christian Mazelle, Gina A. DiBraccio, Jasper S. Halekas, Suranga Ruhunusiri
  • Organizer: 第150回SGEPSS総会および講演会
• [Presentation] MAVEN および Mars Express による火星電離圏不規則構造の遠隔・直接同時観測 (2021)
  • Author(s): 坂東日菜, 原田裕己, 寺田直樹, 中川広務
  • Organizer: 第150回SGEPSS総会および講演会
• [Presentation] Reconnection Jets Observed by MAVEN Around Mars: Preliminary Estimates of Ion Escape Rates (2021)
  • Author(s): Harada, Y., J. S. Halekas, S. Xu, G. A. DiBraccio, S. Ruhunusiri, T. Hara, J. P. McFadden, J. Espley, D. L. Mitchell, C. Mazelle
  • Organizer: MAVEN PSG
  • Int'l Joint Research
• [Presentation] Magnetosonic waves driven by proton ring distributions in the Martian magnetosphere (2020)
  • Author(s): Harada, Y., S. Ruhunusiri, J. S. Halekas, J. Espley, G. A. DiBraccio, J. P. McFadden, D. L. Mitchell, C. Mazelle, G. Collinson, D. A. Brain, T. Hara, M. Nose, S. Oimatsu, K. Yamamoto, and B. M. Jakosky
  • Organizer: JpGU-AGU Joint Meeting 2020: Virtual
  • Int'l Joint Research / Invited
• [Presentation] Survey of dayside reconnection signatures at Mars with MAVEN (2020)
  • Author(s): Harada, Y., J. S. Halekas, G. A. DiBraccio, S. Xu, S. Ruhunusiri, T. Hara, J. Espley, J. P. McFadden, D. L. Mitchell, C. Mazelle
  • Organizer: JpGU-AGU Joint Meeting 2020: Virtual
  • Int'l Joint Research
• [Presentation] A survey of ion jets within current sheets in the vicinity of Mars with MAVEN (2020)
  • Author(s): Harada, Y., J. S. Halekas, S. Xu, G. A. DiBraccio, S. Ruhunusiri, T. Hara, J. P. McFadden, J. Espley, D. L. Mitchell, C. Mazelle
  • Organizer: 第148回SGEPSS総会および講演会
• [Presentation] Reconnection jets within current sheets around Mars (2020)
  • Author(s): Harada, Y., J. S. Halekas, S. Xu, G. A. DiBraccio, S. Ruhunusiri, T. Hara, J. P. McFadden, J. Espley, D. L. Mitchell, C. Mazelle
  • Organizer: Uji Reconnection Workshop 2020
• [Presentation] Global survey of ion flow acceleration within current sheets in the Martian magnetosphere with MAVEN (2020)
  • Author(s): Harada, Y., J. S. Halekas, S. Xu, G. A. DiBraccio, S. Ruhunusiri, T. Hara, J. P. McFadden, J. Espley, D. L. Mitchell, C. Mazelle
  • Organizer: AGU Fall Meeting 2020
  • Int'l Joint Research
• [Presentation] ULF Waves in the Ionosphere of Mars (2020)
  • Author(s): Harada, Y., S. Ruhunusiri, J. S. Halekas, J. Espley, G. A. DiBraccio, J. P. McFadden, D. L. Mitchell, C. Mazelle, G. Collinson, D. A. Brain, T. Hara, M. Nose, S. Oimatsu, K. Yamamoto, and B. M. Jakosky
  • Organizer: 21st Symposium on Planetary Sciences
• [Presentation] Locally generated ULF waves in the Martian magnetosphere (2019)
  • Author(s): Harada, Y., S. Ruhunusiri, J. S. Halekas, J. Espley, G. A. DiBraccio, J. P. McFadden, D. L. Mitchell, C. Mazelle, G. Collinson, D. A. Brain, T. Hara, M. Nose, S. Oimatsu, K. Yamamoto, and B. M. Jakosky
  • Organizer: MAVEN PSG
  • Int'l Joint Research
• [Presentation] Internally generated ULF waves in the Martian magnetosphere (2019)
  • Author(s): Harada, Y., S. Ruhunusiri, J. S. Halekas, J. Espley, G. A. DiBraccio, J. P. McFadden, D. L. Mitchell, C. Mazelle, G. Collinson, D. A. Brain, T. Hara, M. Nose, S. Oimatsu, K. Yamamoto, and B. M. Jakosky
  • Organizer: 第146回SGEPSS総会および講演会
• [Presentation] MAVEN observations of internally generated ULF waves in the upper ionosphere of Mars (2019)
  • Author(s): Harada, Y., S. Ruhunusiri, J. S. Halekas, J. Espley, G. A. DiBraccio, J. P. McFadden, D. L. Mitchell, C. Mazelle, G. Collinson, D. A. Brain, T. Hara, M. Nose, S. Oimatsu, K. Yamamoto, and B. M. Jakosky
  • Organizer: AGU Fall Meeting 2019
  • Int'l Joint Research