講演情報
[PEM15-P09]Investigation of precipitating electrons of the Omega-Band Aurora
*長縄 一輝1、三好 由純1、栗田 怜2、細川 敬祐3、大山 伸一郎1、小川 佳美4、笠原 禎也5、松田 昇也5、堀 智昭1、Wang Shiang-Yu6、風間 洋一6、Jun Chae-Woo1、笠原 慧7、横田 勝一郎8、桂華 邦裕7、松岡 彩子2、寺本 万里子9、山本 和弘1、篠原 育10 (1.名古屋大学、2.京都大学、3.電気通信大学、4.国立極地研究所、5.金沢大学、6.ASIAA、7.東京大学、8.大阪大学、9.九州工業大学、10.ISAS/JAXA)
キーワード：
オーロラ、オメガバンド、あらせ、ELFIN
The Omega band auroras are a type of aurora that occur after auroral breakups, characterized by a structure resembling an inverted Greek letter Omega (Ω). These auroras drift eastward from midnight towards dawn. Also, it has also been revealed that Omega band auroras are composed of various types of auroras, including diffuse, pulsating, and discrete auroras within the torch structures. Previous studies on Omega band auroras have proposed several hypotheses regarding their origins. It is suggested that Omega band is caused by velocity shear resulting from a hybrid of Kelvin-Helmholtz and Rayleigh-Taylor instabilities. Another model, the streamer model, proposes that the poleward auroral streamer directly evolves into the Omega band torch. However, the magnetospheric mechanisms responsible for Omega band auroras remain unclear due to a lack of simultaneous observations in the magnetosphere. This study aims to clarify the dynamics of plasma and waves in the magnetosphere associated with the auroral structures in the Omega band. We analyze ground-based observations at two wavelengths (427.8 nm and 844.6 nm), using two EMCCD cameras installed in Tromsø, Norway, along with conjugate observations by low-altitude satellite as well as the Arase satellite data. In this presentation, we will report on the spatial characteristics of precipitating electrons within the Omega band auroras and their correspondence with phenomena observed Omega band events.