[P-EM11] Dynamics of the Inner Magnetospheric System

[PEM11-P17] Electron hybrid code simulation of the whistler-mode chorus generation based on the RAM/SCB results of the March 2017 storm

*加藤 雄人¹、三好 由純²、Jordanova Vania³、栗田 怜⁴、松田 昇也⁵、齊藤 慎司⁶ (1.東北大学大学院理学研究科地球物理学専攻、2.名古屋大学宇宙地球環境研究所、3.Los Alamos National Laboratory、4.京都大学生存圏研究所、5.金沢大学理工研究域、6.情報通信研究機構)

キーワード：inner magnetosphere、whistler-mode chorus、energetic electrons、numerical simulation

We carry out a series of self-consistent electron hybrid code simulations (Katoh and Omura, 2007; Katoh et al., 2018) for the whistler-mode chorus generation in the inner magnetosphere, based on results of ring current-atmosphere interactions model with self-consistent magnetic field (RAM-SCB; Jordanova et al., 2012) for the March 2017 storm. Rising tone chorus emissions were observed by the Arase satellite during the storm in the morning side of the magnetosphere at L=6. RAM-SCB results provide the evolution of the distribution function of energetic electrons during the storm. The electron hybrid code simulation enables us to study the condition required for the chorus generation, governed by fully nonlinear processes of wave-particle interactions. We select a snapshot of the RAM-SCB result at the timing when the enhancement of whistler-mode chorus emissions is expected. The bi-Maxwellian type velocity distribution function, N_h*f(v_||, v_⊥), is constructed from the RAM-SCB result, where N_h is the number density of energetic electrons, f is the probability distribution function in the velocity space, and v_|| and v_⊥ are the velocity components parallel and perpendicular to the background magnetic field, respectively. We use f(v_||, v_⊥) for the electron hybrid code simulation's initial condition and conduct a survey for N_h required to generate rising tone chorus. By comparing N_h determined from the survey and those obtained by the RAM-SCB simulations, we discuss the property of the chorus generation during the storm time.