Study of auroral current system using multi-satellite observations

• Project/Area Number: 16K05568
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Space and upper atmospheric physics
• Research Institution: Nagoya University
• Principal Investigator: Ieda Akimasa 名古屋大学, 宇宙地球環境研究所, 助教 (70362209)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000); Fiscal Year 2019: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2018: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2017: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2016: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
• Keywords: オーロラ爆発 / オーロラ電流系 / 磁気リコネクション / 電離圏電気伝導度 / 衝突周波数 / 酸素 / 電気伝導度 / 電荷交換衝突 / 国際情報交流（米国） / オーロラ / 電離圏 / 磁力線再結合 / 編隊衛星

Outline of Final Research Achievements

Aurora near the midnight polar ionosphere (100 km altitude) brightens explosively approximately every a few hours. This auroral breakup is supposed to represent an electrical short of the current flowing in the magnetotail (50-200 million meters) into the ionosphere. We studied auroral breakup using simultaneous ground-satellite observations. In particular, we clarified the reason why auroral breakup jumps to a higher latitude every 10 min. We also clarified the reason why auroral breakup looks different between ground observations and satellite observations.

Academic Significance and Societal Importance of the Research Achievements

オーロラは宇宙から降下する電子が地球の中性大気を励起することにより発生する。すなわち、オーロラ爆発は恒星大気と惑星大気が激しく相互作用していることを意味しており、オーロラ爆発を理解することは宇宙と地球の境界領域を理解することである。この近宇宙領域は国際宇宙ステーション（高度400 km）や気象衛星軌道(高度4万km)を含み、そこでの電磁気擾乱を理解することは人類の宇宙活動に貢献すると考えられる。

Research Products

• [Int'l Joint Research] Finnish Meteorological Institute(フィンランド)
• [Int'l Joint Research] University of California/Boston University(米国)
• [Int'l Joint Research] 韓国天文宇宙科学研究院(韓国)
• [Int'l Joint Research] University of Southampton/Lancaster University(英国)
• [Int'l Joint Research] Finnish Meteorological Institute(フィンランド)
• [Int'l Joint Research] University of California/Boston University(米国)
• [Int'l Joint Research] 韓国天文宇宙科学研究院(韓国)
• [Int'l Joint Research] University of Southampton/Lancaster University(英国)
• [Journal Article] Ion‐neutral collision frequencies for calculating ionospheric conductivity (2020)
  • Author(s): Ieda Akimasa
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 125 Issue: 2
  • DOI: 10.1029/2019ja027128
  • Peer Reviewed
• [Journal Article] Simultaneous observation of auroral substorm onset in Polar satellite global images and ground-based all-sky images (2018)
  • Author(s): Ieda Akimasa、Kauristie Kirsti、Nishimura Yukitoshi、Miyashita Yukinaga、Frey Harald U.、Juusola Liisa、Whiter Daniel、Nose Masahito、Fillingim Matthew O.、Honary Farideh、Rogers Neil C.、Miyoshi Yoshizumi、Miura Tsubasa、Kawashima Takahiro、Machida Shinobu
  • Journal Title: Earth, Planets and Space Volume: 70 Issue: 1 Pages: 1-18
  • DOI: 10.1186/s40623-018-0843-3
  • NAID: 120006537089
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Revisiting substorm events with preonset aurora (2018)
  • Author(s): Miyashita Yukinaga、Ieda Akimasa
  • Journal Title: Annales Geophysicae Volume: 36 Issue: 5 Pages: 1419-1438
  • DOI: 10.5194/angeo-36-1419-2018
• [Journal Article] Stepwise tailward retreat of magnetic reconnection: THEMIS observations of an auroral substorm (2016)
  • Author(s): A. Ieda, Y. Nishimura, Y. Miyashita, V. Angelopoulos, A. Runov, T. Nagai, H. U. Frey, D. H. Fairfield, J. A. Slavin, H. Vanhamäki, H. Uchino, R. Fujii, Y. Miyoshi, and S. Machida
  • Journal Title: Journal of Geophysical Research Space Physics Volume: 121 Issue: 5 Pages: 4548-4568
  • DOI: 10.1002/2015ja022244
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Presentation] Auroral substorm onset in satellite-based global images and ground-based all-sky images (2019)
  • Author(s): Akimasa Ieda, Kirsti Kauristie, Yukitoshi Nishimura, Yukinaga Miyashita, Harald U. Frey , Liisa Juusola, Daniel Whiter, Masahito Nose, Matthew O. Fillingim, Farideh Honary, Neil C. Rogers , Yoshizumi Miyoshi, Tsubasa Miura, Takahiro Kawashima and Shinobu Machida
  • Organizer: Japan geoscience union joint meeting 2019
  • Int'l Joint Research
• [Presentation] 電離圏電気伝導度を算出するための衝突周波数 (2019)
  • Author(s): 家田 章正
  • Organizer: 第146回 地球電磁気・地球惑星圏学会総会および講演会
• [Presentation] MMS衛星群とGeotail衛星によるサブストーム開始の同時観測 (2018)
  • Author(s): 家田 章正, 北村 成寿, 齋藤 義文, 横田 勝一郎, Pollock Craig J., Giles Barbara L., Russell C. T., 町田 忍, 長井 嗣信, 熊本 篤志, 土屋 史紀, 笠原 禎也, 三好 由純
  • Organizer: 第144回 SGEPSS総会および講演会
• [Presentation] Simultaneous observation of auroral substorm onset in Polar satellite global images and ground-based all-sky images (2017)
  • Author(s): A. Ieda, S. Machida, Y. Miyoshi, T. Kawashima, T. Miura, K. Kauristie, Y. Nishimura, Y. Miyashita, G.K. Parks, M. O. Fillingim
  • Organizer: Japan Geoscience Union meeting 2017
  • Int'l Joint Research
• [Presentation] Simultaneous observation of auroral substorm onset in Polar satellite global images and ground-based all-sky images (2017)
  • Author(s): A. Ieda, K. Kauristie, L. Juusola, Y. Nishimura, Y. Miyashita, D. H. Fairfield, H. U. Frey, M. O. Fillingim, D. Whiter, F. Honary, N. C. Rogers, Y. Miyoshi, and S. Machida
  • Organizer: International conference on substorms 13
  • Int'l Joint Research / Invited
• [Presentation] オーロラキロメートル放射とオーロラ極方向拡大との関係：Geotail衛星と地上全天観測 (2017)
  • Author(s): 家田章正、宮下幸長、町田忍、三浦翼、川嶋貴大
  • Organizer: 地球電磁気・地球惑星圏学会第142 回総会・講演会
• [Presentation] MMS satellites and EISCAT radar observations of dayside flow bursts (2016)
  • Author(s): A. Ieda, Y. Ogawa, S. Oyama, N. Kitamura, Y. Saito, S. Yokota, H. Hasegawa, S. Taguchi, K. Hosokawa, S. Machida, H. Uchino, T. Hori, C. J. Pollock, B. L. Giles, T. E. Moore, C. T. Russell, R. J. Strangeway, R. Nakamura, and J. L. Burch
  • Organizer: 日本地球惑星科学連合2016年大会
  • Place of Presentation: 幕張メッセ、千葉市
  • Int'l Joint Research
• [Presentation] オーロラ爆発の衛星画像と全天画像による同時観測 (2016)
  • Author(s): 家田章正,西村幸敏,宮下幸長,町田忍,川嶋貴大,三浦翼
  • Organizer: 地球電磁気・地球惑星圏学会第140 回総会・講演会
  • Place of Presentation: 九州大学、福岡市