[P-EM13] Dynamics of the Inner Magnetospheric System

[PEM13-14] Average Profiles of Outer Radiation Belt Electron Flux and Related Plasma Parameters During Magnetic Storms: Insights from Arase Observations and Simulations

*Yoshizumi Miyoshi¹, Sandeep Kumar², Satoshi Kurita³, Shinji Saito⁴, Shoya Matsuda⁵, Yuto Katoh⁶, Ryuho Kataoka⁷, Rui Chen⁸, Shreedevi Porunakatu Radhakrishna¹, Iku Shinohara⁹, Kazushi Asamura⁹, Yoichi Kazama¹⁰, Shiang-Yu Wang¹⁰, Chae-Woo Jun¹, Tomoaki Hori¹, Satoshi Kasahara¹¹, Shoichiro Yokota¹², Kunihiro Keika¹¹, Takefumi Mitani⁹, Takeshi Takashima⁹, Nana Higashio⁹, Yoshiya Kasahara⁵, Fuminori Tsuchiya¹³, Atsushi Kumamoto¹³, Atsuki Shinbori¹, Naritoshi Kitamura¹, Ayako Matsuoka³, Kazuhiro Yamamoto¹, Mariko Teramoto¹³ (1.Institute for Space-Earth Environmental Research, Nagoya University, 2.NASA/GSFC, 3.Kyoto University, 4.NICT, 5.Kanazawa University, 6.Tohoku University, 7.NIPR, 8.Auburn University, 9.JAXA, 10.ASIAA, 11.University of Tokyo, 12.Osaka University, 13.Kyushu Instituite for Technology)

Keywords:Arase satellite, inner magnetosphere, radiation belts, wave-particle interactions

The Arase satellite has successfully observed the inner magnetosphere for over eight years, providing continuous data on a wide range of electron energy and various plasma waves. We conducted a superposed epoch analysis of electrons at different energies, including source and seed populations, as well as plasma density and plasma waves. The result was sorted as a function of L-shell, magnetic local time (MLT), and storm phase to identify the average variations in these key parameters that contribute to the acceleration of relativistic electrons in the outer radiation belt. The results are consistent with the concept of cross-energy coupling, in which wave-particle interactions play a crucial role. In particular, prolonged substorm activities that drive continuous chorus waves through hot electron flux enhancements are essential for the buildup of relativistic electrons via wave-particle interactions. We also compare these findings with data-driven simulations of the evolution of the electron energy spectrum to discuss potential acceleration mechanisms.