[P-EM12] Dynamics of the Inner Magnetospheric System

[PEM12-12] Long period modulations of pulsating aurora and chorus waves

*Yoshizumi Miyoshi¹, Keisuke Hosokawa², Yasunobu Ogawa³, Satoshi Kurita⁴, Shin-ichiro Oyama¹, Mariko Teramoto⁵, Shinji Saito⁶, Yoshiya Kasahara⁷, Shoya Matsuda⁸, Satoshi Kasahara⁹, Shoichiro Yokota¹⁰, Kunihiro Keika⁹, Tomoaki Hori¹, Fuminori Tsuchiya¹¹, Atsushi Kumamoto¹¹, Satoko Nakamura¹, Masahiro Kitahara¹, Masafumi Shoji¹, Ayako Matsuoka⁴, Shun Imajo¹, Iku Shinohara⁸ (1.Institute for Space-Earth Environmental Research, Nagoya University, 2.The University of Electro-Communications, 3.NIPR, 4.Kyoto University, 5.Kyushu Inst. of Technology, 6.NICT, 7.Kanazawa University, 8.JAXA, 9.University of Tokyo, 10.Osaka University, 11.Tohoku University)

Keywords:Arase, chorus, pulsating aurora

Pulsating aurora (PsA) is primarily caused by intermittent precipitation of tens of keV electrons by the magnetospheric chorus waves. Variations of different time scales have been known to exist in the optical emission amplitude of PsA: the main pulsations of PsA with a few seconds are caused by chorus bursts and internal modulations of PsA within 1 second are caused by chorus short-lived elements composing the bursts. Here, we report chorus bundles that appear every a few tens of seconds as observed by Arase/PWE observations. Each chorus bundle includes several chorus bursts. In association with chorus bundles in the magnetosphere, we observed temporal variations in a series of the main pulsation of PsA using ground based EMCCD cameras. During the period of chorus bundles, continuous activities of main pulsations were observed. Concurrently, enhancements in the temperature anisotropy of tens of keV electrons as well as ULF pulsations were observed by Arase/MEPe and MGF, respectively. In this presentation, we report fundamental characteristics of chorus bundles and the corresponding signatures of PsA and discuss possible mechanisms to cause the long period modulations in order to fully understand the hierarchical temporal variation of PsA.