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

[PEM16-18] Magnetic field disturbances observed by Arase (ERG) associated with the magnetic dipolarization

*Ayako Matsuoka¹, Masahito Nose², Yoshizumi Miyoshi³, Mariko Teramoto³, Reiko Nomura⁴, Akiko Fujimoto⁵, Yoshimasa Tanaka⁶, Manabu Shinohara⁷, Yoshiya Kasahara⁸, Yasumasa Kasaba⁹, Keigo Ishisaka¹⁰, Shoya Matsuda³, Masafumi Shoji³, Tomoko Nakagawa¹¹, Iku Shinohara¹ (1.Research Division for Space Plasma, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 2.Graduate School of Science, Kyoto University, 3.Institute for Space-Earth Environmental Research, Nagoya University, 4.Environmental Test Technology Unit, Japan Aerospace Exploration Agency, 5.International Center for Space Weather Science and Education, Kyushu University, 6.National Institute of Polar Research, 7.National Institute of Technology, Kagoshima College, 8.Graduate School of Natural Science and Technology, Kanazawa University, 9.Graduate School of Science, Tohoku University, 10.Faculty of Engineering, Toyama Prefectural University, 11.Tohoku Institute of Technology)

Keywords:Arase, magnetic field, dipolarization

It is known that magnetic field disturbances often appear in the night-side magnetosphere associated with the magnetic dipolarization. The disturbances carry significant energy which is considered to be released by the global configuration change of the magnetosphere, The energy normally directs to the earth in the inner magnetosphere at the several Re distance from the earth. It suggests that the disturbances are generated in the near-earth magnetotail region, presumably about 10 Re distance from the earth. However, it is not still very clear how the magnetic field disturbances are excited and affect the particle motion in the inner magnetosphere.

The Arase (ERG) satellite was launched on December 20, 2016, to investigate the plasma physics in the inner magnetosphere. The energy exchange between particles and fields is one of the major subjects of the Arase project. We are studying the magnetic dipolarization and associated disturbances observed by Arase. The characteristics (compressibility, polarization, propagation direction, and so on) are investigated for typical events to limit the generation mechanism of the disturbances. Very close investigation of the disturbances should lead to the future statistical study, occurrence ratio, distribution and relation with the particle signature.