[P-EM12] Dynamics of the Inner Magnetospheric System

[PEM12-P32] Plasma waves causing 20 Hz intensity modulation of pulsating aurora: High-speed Tjörnes-Arase-Syowa conjugate observation

*内田 ヘルベルト陽仁¹、片岡 龍峰^2,1、村瀬 清華¹、松田 昇也³、笠原 禎也⁴、小路 真史⁵、三好 由純⁵、篠原 育³、松岡 彩子⁶、栗田 怜⁷、細川 敬祐⁸、今城 峻⁵ (1.総合研究大学院大学、2.国立極地研究所、3.宇宙航空研究開発機構宇宙科学研究所、4.金沢大学、5.名古屋大学宇宙地球環境研究所、6.京都大学、7.京都大学生存圏研究所、8.電気通信大学)

キーワード：脈動オーロラ、コーラス波動、高速撮像

We show the evidence of the simultaneously observed ~20 Hz intensity modulation of the auroral luminosity and the chorus wave intensity, and the evolution of pulsating aurora in terms of the transition of on and off of the pulsating patch, patch size, and pulsating period in different timescales. Pulsating auroras were observed by ground-based high-speed imagers after an auroral breakup at Tjörnes in Iceland and at its magnetic conjugate station, Syowa Station in Antarctica simultaneously on 22 September 2018. Two identical all-sky imagers at both stations and a narrow field-of-view imager at Syowa station were used to elucidate the hierarchical structure of the modulation in the auroral luminosity and the evolution of pulsating patches at different time scales. A few minutes before the main pulsation start, a fast intensity modulation of ~20 Hz was identified by the narrow field-of-view imager with ~3 Hz modulation in a small aurora patch. The foot-print of the Arase satellite was located within the all-sky field of view at that time, and the Plasma Wave Experiment onboard the Arase satellite observed chorus emissions whose intensity was modulated at the same period of the auroral fast intensity modulation. The patch size and the pulsation period evolved in time at both hemispheres and the period settled in the period of main pulsation. The pulsating patches differ in its shape and period between both hemispheres although several synchronized patches were also observed when the pulsating aurora drifted away from the all-sky field-of-view.