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

[PEM16-01] Energetic electron acceleration and precipitations associated with chorus waves; Arase observations

*Yoshizumi Miyoshi¹, Shinji Saito¹, Satoshi Kurita¹, Yoshiya Kasahara², Shoya Matsuda¹, Fuminori Tsuchiya³, Atsushi Kumamoto³, Ayako Matsuoka⁴, Nana Higashio⁴, Takefumi Mitani⁴, Takeshi Takashima⁴, Satoshi Kasahara⁵, Shoichiro Yokota⁶, Kazushi Asamura⁴, Iku Shinohara⁴, Kazuo Shiokawa¹, Yasunobu Ogawa⁷, Keisuke Hosokawa⁸, Shin-ichiro Oyama¹, Tomoaki Hori¹, Masafumi Shoji¹, Mariko Teramoto¹, Tzu-Fang Chang¹, Esa Turunen⁹ (1.Institute for Space-Earth Environmental Research, Nagoya University, 2.Kanazawa University, 3.Tohoku University, 4.JAXA, 5.The University of Tokyo, 6.Osaka University, 7.NIPR, 8.UEC, 9.SGO, Finland)

Keywords:Radiation Belts, Precipitation, wave-particle interactions

The whistler mode chorus waves work dual role for the acceleration and precipitation of energetic electrons. The Arase satellite that was launched in December, 2016 has obtained comprehensive data sets for plasma/particles and fields/waves. In March and April, 2017, the Arase satellite observed several magnetic disturbances driven by CIR and subsequent coronal hole streams. During the period, the Arase satellite observed continuous chorus activities for a few days associated with the high-speed solar wind. During this period, comprehensive observations from the Arase satellite and ground-based observations are realized. EISCAT at Tromso, Norway observed strong ionization at the low altitude, indicating sub-relativistic electrons of the radiation belts precipitate into the atmosphere. During the period, the Arase satellite successfully observed intense chorus waves outside the plasmapause, indicating the resonance with chorus waves causes the pitch angle scattering of energetic electrons. Simultaneously, large flux enhancement of the outer belt electrons was observed with enhancement of chorus waves. We discuss the dual role that chorus waves play in controlling the dynamics of the radiation belts.