日本地球惑星科学連合2024年大会

講演情報

[E] ポスター発表

セッション記号 P (宇宙惑星科学) » P-EM 太陽地球系科学・宇宙電磁気学・宇宙環境

[P-EM13] Dynamics of the Inner Magnetospheric System

2024年5月26日(日) 17:15 〜 18:45 ポスター会場 (幕張メッセ国際展示場 6ホール)

コンビーナ:桂華 邦裕(東京大学大学院理学系研究科地球惑星科学専攻)、三好 由純(名古屋大学宇宙地球環境研究所)、Sarris E Sarris(Democritus University of Thrace)、Thomas G Thomas(Dartmouth College)


17:15 〜 18:45

[PEM13-P20] Statistical study of nonlinear EMIC wave-particle interaction on relativistic electrons in the magnetosphere observed by the Arase and Van Allen Probes

*Chae-Woo Jun1Yoshizumi Miyoshi1Tomoaki Hori1Khan-Hyuk Kim2、Jacob Bortnik3、Larry Lyons3Takefumi Mitani4Takeshi Takashima4Iku Shinohara4、N. Higashio4Ayako Matsuoka5Yoshiya Kasahara6Shoya Matsuda6Yasumasa Kasaba7 (1.Institute for Space-Earth Environmental Research, Nagoya University、2.Kyung-Hee University, Suwon, Korea、3.Atmospheric and Oceanic Sciences, University of California Los Angeles, Los Angeles, USA、4.Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Japan. 、5.Kyoto University, Kyoto, Japan、6.Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan、7.Graduate School of Science, Tohoku University, Sendai, Japan)

キーワード:EMIC rising-tone emissions with MeV electrons, In-situ observations using the Arase and Van Allen Probes, Wave-particle interaction in the inner magnetosphere

Electromagnetic ion cyclotron (EMIC) waves are known to play an important role in contributing to loss of relativistic (~ MeV) electrons in the outer radiation belts through pitch-angle scattering due to wave-particle interaction. Previous theoretical studies suggested that EMIC rising-tone emissions triggered by nonlinear wave growth can cause rapid losses of relativistic electrons in the inner magnetosphere. Our previous studies found the compressed dayside magnetosphere with the homogeneous magnetic field (dB/ds ~ 0) from the magnetic equator to higher magnetic latitudes provides a preferred condition for triggering nonlinear EMIC waves and these waves can interact with even sub-MeV electrons, leading to precipitation into the ionosphere. However, the influence of nonlinear EMIC wave-particle interactions on MeV electrons in the inner magnetosphere is not well understood yet. To clarify the relationship between nonlinear EMIC waves and MeV electrons in the magnetosphere, we perform a statistical study of relativistic electron variations associated with nonlinear EMIC waves using the Arase and Van Allen Probes. We select enhanced EMIC rising-tone emissions observed by either of the two missions from 2013 to 2023 for the recent solar cycle and classify the events into two categories: MeV flux variations associated with EMIC rising-tone emissions and weak relationships between them. Then, we investigate the characteristics (e.g., polarization sense, wave normal angle, Poynting vector, spatial distributions, solar activity, geomagnetic conditions, etc) of each category and compare them with each other. We discuss the underlying physical processes causing the loss of relativistic electrons in the outer radiation belt through EMIC wave-particle interactions.