[P-EM16] Dynamics of Earth's Inner Magnetosphere and Initial Results from Arase

[PEM16-32] Ion hole formation and nonlinear generation of Electromagnetic Ion Cyclotron waves: THEMIS observations

★Invited Papers

*小路 真史¹、三好 由純¹、加藤 雄人²、桂華 邦裕³、Vassilis Angelopoulos⁴、笠原 慧³、浅村 和史⁵、中村 紗都子⁶、大村 善治⁶ (1.名古屋大学宇宙地球環境研究所、2.東北大学、3.東京大学、4.カリフォルニア大学ロサンゼルス校、5.宇宙科学研究所、6.京都大学生存圏研究所)

キーワード：波動粒子相互作用、非線形波動成長

Electromagnetic plasma waves are thought to be responsible for energy exchange between charged particles in space plasmas. Such an energy exchange process is evidenced by phase space holes identified in the ion distribution function and measurements of the dot product of the plasma wave electric field and the ion velocity. We develop a method to identify ion hole formation, taking into consideration the phase differences between the gyro-motion of ions and the electromagnetic ion cyclotron (EMIC) waves. Using this method, we identify ion-holes in the distribution function and the resulting nonlinear EMIC wave evolution from THEMIS observations. {These} ion holes are key to wave growth and frequency drift by the ion currents through nonlinear wave particle interactions, which are identified by a computer simulation in this study.