日本地球惑星科学連合2019年大会

講演情報

[E] 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-EM15] 太陽地球系結合過程の研究基盤形成

2019年5月30日(木) 17:15 〜 18:30 ポスター会場 (幕張メッセ国際展示場 8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)、吉川 顕正(九州大学大学院理学研究院地球惑星科学部門)

[PEM15-P02] Detached cusp aurora for southward IMF

*高須 浩平1田口 聡1細川 敬祐2 (1. 京都大学大学院理学研究科地球惑星科学専攻地球物理学教室、2.電気通信大学大学院情報理工学研究科)

キーワード:オーロラ、カスプ、プラズマ対流、惑星間空間磁場

A poleward-moving aurora is a typical phenomenon in the dayside cusp of the high-latitude ionosphere. This aurora usually originates near the equatorward boundary of the cusp, and diminishes near the poleward boundary of the persistent cusp auroral emissions. In this study we have examined faint poleward-moving auroras that are detached from the persistent cusp emissions by analyzing 630-nm aurora image data from an all-sky imager at Longyearbyen, Svalbard, and precipitating electron data from DMSP spacecraft. These auroras occur for southward IMF, and are located at latitudes higher than 80 MLAT. The intensities are very weak (less than 1 kilo Rayleigh). The result of the analysis shows that the speed of the auroral motion is 1 to 2 km/s, which is faster than typical convection speed in the dayside polar cap. We show the similarities and differences between the faint aurora and the typical poleward moving cusp aurora, and discuss how soft electron precipitation occurs in the region that is well separated from the cusp.