日本地球惑星科学連合2018年大会

講演情報

[EE] ポスター発表

セッション記号 P (宇宙惑星科学) » P-EM 太陽地球系科学・宇宙電磁気学・宇宙環境

[P-EM13] 太陽地球系結合過程の研究基盤形成

2018年5月20日(日) 15:30 〜 17:00 ポスター会場 (幕張メッセ国際展示場 7ホール)

コンビーナ:山本 衛(京都大学生存圏研究所)、小川 泰信(国立極地研究所)、野澤 悟徳(名古屋大学宇宙地球環境研究所、共同)、吉川 顕正(九州大学大学院理学研究院地球惑星科学部門)

[PEM13-P10] Conjugate observations of the evolution of polar cap arcs in both hemispheres

*Zan-Yang Xing1Qing-He Zhang1De-Sheng Han2,6Yong-Liang Zhang3Natsuo Sato4Shunrong Zhang5Ze-Jun Hu2Yong WANG1Yu-Zhang Ma1 (1.Institute of Space Sciences, Shandong University at Weihai、2.Polar Research Institute of China、3.Applied Physics Laboratory, The Johns Hopkins University、4.National Institute of Polar Research、5.MIT Haystack Observatory、6.Tongji University)

キーワード:Polar cap arc, Conjugacy, Interplanetary magnetic field

We report results from the analysis of a case of conjugate polar cap arcs (PCAs) observed on February 5, 2006 in the northern hemisphere by the ground based Yellow River Station all-sky imager (Svalbard) and in both hemispheres by the space based DMSP/SSUSI and TIMED/GUVI instruments. The PCAs motion in dawn-dusk direction shows a clear dependence on the interplanetary magnetic field (IMF) By component and presents a clear asymmetry between southern and northern hemispheres, i.e., formed on the duskside and moving from dusk to dawn in the northern hemisphere and vice versa in the other hemisphere. The already existing PCAs’ motion is influenced by the changes in the IMF By with a time delay of ~70 minutes. We also observed strong flow shears/reversals around the PCAs in both hemispheres. The precipitating particles observed in the ionosphere associated with PCAs showed properties of boundary layers plasma. Based on these observations, we might reasonably expect that the topological changes in the magnetotail can produce a strip of closed field lines and local processes would be set up conditions for the formation and evolution of PCAs.