[P-EM18] 磁気圏-電離圏ダイナミクス

[PEM18-P04] 太陽風動圧急増に伴う放射線帯電子の加速：GEMSIS-RB/GEMSIS-GM連成シミュレーション

*林 昌広¹、三好 由純¹、齊藤 慎司¹、松本 洋介²、桂華 邦裕¹、堀 智昭¹、天野 孝伸³、関 華奈子³、町田 忍¹ (1.名古屋大学宇宙地球環境研究所、2.千葉大学、3.東京大学)

キーワード：放射線帯、電子の加速、GEMSIS

Relativistic electron fluxes of the outer radiation belt dynamically change in response to solar wind variations. There exist several time scales for the outer belt flux enhancement. One of the shortest processes is caused by wave-particle interactions between drifting electrons and fast-mode waves induced by compression of magnetosphere caused by interplanetary shock (e.g., Li et al., 1993). In recent years, Van Allen Probes spacecraft observations indicated that electrons whose drift velocity is close to the fast-mode velocity are selectively accelerated (Foster et al., 2015). In this study, we performed a code coupling simulation using GEMSIS-RB test particle simulation (Saito et al., 2010) and GEMSIS-GM global MHD magnetosphere simulation (Matsumoto et al., 2010) to investigate how relativistic electrons are accelerated by fast-mode waves induced by solar wind pressure pulses. We simulated electron motions with different initial L-shells and initial energies and investigated how electrons are accelerated effectively by fast-mode waves launched at dayside magnetopause . As a result of the analysis, we found that electron acceleration strongly depends on both initial positions and initial energies of electrons. Effective accelerations are observed at high energy electrons at larger L-shells. We suggest that the effective acceleration occurs when electron’s drift velocity is faster than fast-mode velocity.