[P-EM12] Dynamics of the Inner Magnetospheric System

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

*三好 由純¹、細川 敬祐²、小川 泰信³、栗田 怜⁴、大山 伸一郎¹、寺本 万里子⁵、齊藤 慎司⁶、笠原 禎也⁷、松田 昇也⁸、笠原 慧⁹、横田 勝一郎¹⁰、桂華 邦裕⁹、堀 智昭¹、土屋 史紀¹¹、熊本 篤志¹¹、中村 紗都子¹、北原 理弘¹、小路 真史¹、松岡 彩子⁴、今城 峻¹、篠原 育⁸ (1.名古屋大学宇宙地球環境研究所、2.電気通信大学、3.国立極地研究所、4.京都大学、5.九州工業大学、6.情報通信研究機構、7.金沢大学、8.宇宙航空研究開発機構、9.東京大学、10.大阪大学、11.東北大学)

キーワード：あらせ衛星、コーラス、脈動オーロラ

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.