Plasma Waves Causing Relativistic Electron Precipitation Events at International Space Station: Lessons From Conjunction Observations With Arase Satellite
Ryuho Kataoka, Y. Asaoka, S. Torii, S. Nakahira, H. Ueno, Shoko Miyake, Yoshizumi Miyoshi, Satoshi Kurita, Masafumi Shoji, Yoshiya Kasahara, Mitsunori Ozaki, Shoya Matsuda, Ayako Matsuoka, Yasumasa Kasaba, Iku Shinohara, Keisuke Hosokawa, Herbert Akihito Uchida, Kiyoka Murase, Yoshimasa Tanaka
Abstract
Abstract We report three different types of relativistic electron precipitation (REP) events observed at International Space Station (ISS), associated with electromagnetic ion cyclotron (EMIC) waves or whistler mode waves as observed by the Arase satellite at conjugate locations near the magnetic equator. Three different detectors installed on the ISS were complementarily used; CALET/CHD as the detector of precipitating MeV electrons, MAXI/RBM as the detector of sub‐MeV electrons from horizontal and vertical directions, and SEDA‐AP/SDOM to quantitatively measure the energy spectrum. The REP event on 21 August 2017 shows a quasiperiodic intensity variation at ~1 Hz which corresponds to variations of the EMIC waves at the Arase altitudes. The REP event on 24 April 2017 shows rapid and irregular intensity variation which corresponds to the amplitude variation of chorus waves, while the REP events on 26 October 2017 shows a smooth quasiperiodic time variation at ~0.2 Hz which corresponds to the amplitude variation of “electrostatic” whistler mode waves. This study clearly demonstrates that the time variation of REP events at ISS are caused by various types of plasma waves near the magnetic equator.