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-EM11] Dynamics of Magnetosphere and Ionosphere

2019年5月29日(水) 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:中溝 葵(情報通信研究機構 電磁波研究所)、尾崎 光紀(金沢大学理工研究域電子情報学系)、藤本 晶子(九州工業大学)、堀 智昭(名古屋大学宇宙地球環境研究所)

[PEM11-P18] Spatiotemporal characteristics on the source region of flash aurora using ray tracing analysis

*井上 智寛1尾崎 光紀1後藤 由貴1八木谷 聡1笠原 禎也1塩川 和夫2三好 由純2片岡 龍峰3海老原 祐輔4 (1.金沢大学、2.名古屋大学、3.国立極地研究所、4.京都大学)

キーワード:フラッシュオーロラ、ホイッスラーモード波動、レイトレーシング、波動粒子相互作用

Whistler mode waves cause precipitation of high-energy electrons via wave-particle interactions in the magnetosphere. The scattered particles precipitate to the ground along the geomagnetic field line. Then, flush aurora, which is a rapid (less than 1 s) auroral phenomenon, is happened. Flash aurora is important for understanding the spatial evolution of wave-particle interaction region in the magnetosphere. We observed the mainly southward spread of flush aurora. In order to understand the spatial-time variation of wave-particle interaction region, we analyze the propagation effects of whistler mode waves near the magnetic equator region using ray tracing analysis. We calculated the ray paths of whistler mode waves (0.2 fce and 0.4 fce) near the magnetic equator (-10 to +10 degrees of geographic latitude), where fce is the electron cyclotron frequency at the magnetic equator. The initial ray paths put in the assumption of a spatial spread with the wave normal angles of tens of degrees along the magnetic field line at the magnetic equator (a point source). Then, we traced the magnetic field lines from the ray paths of whistler mode waves and estimated the precipitation area of electrons in the ionosphere using the IGRF model. The calculation results showed the precipitation area was not mainly spread southward, but evolved northward in the preliminary study.
In this presentation, we will present the spatiotemporal characteristics of flash aurora and the analysis results of ray tracing in detail.