講演情報
[PEM13-P13]Statitstical study of pulsating auroras and ducted chorus waves: Arase - ground joint observations
*伊藤 ゆり1,2、小川 泰信2,1、田中 良昌2,3,1、門倉 昭2,3、吹澤 瑞貴2、細川 敬祐4、三好 由純5、堀 智昭5、笠原 禎也6、松田 昇也6、篠原 育7 (1.総合研究大学院大学、2.国立極地研究所、3.情報・システム研究機構 データサイエンス共同利用基盤施設、4.電気通信大学、5.名古屋大学宇宙地球環境研究所、6.金沢大学、7.宇宙航空研究開発機構／宇宙科学研究所)
キーワード：
脈動オーロラ、ホイッスラーモードコーラス波動、密度ダクト
Pulsating aurora (PsA), which is characterized by quasi-periodic luminosity modulation of ~2–30 sec, is a common aurora associated with ~10 keV electron precipitation. During PsA, much higher energy (i.e., sub-relativistic/relativistic) electrons precipitate into the ionosphere at the same time [Miyoshi et al., 2015; Miyoshi et al., 2021; Oyama et al., 2017]. The highly energetic electrons penetrate to lower altitudes and induce ozone depletion in the mesosphere and the upper stratosphere [Miyoshi et al., 2021]. Our previous study has observationally proposed a "duct model", in which patchy PsA and energetic electron precipitation (EEP) are controlled by the magnetospheric density ducts and the resultant high-latitude propagation of chorus waves [Ito et al., 2024]. Other recent studies have also conducted statistical analyses of ducts, wave propagation latitudes, and PsA types, respectively [Li et al., 2011; Meredith et al., 2020; Tesema et al., 2020]. However, past studies investigated such related phenomena separately and none of them has directly targeted their physical relationship on a statistical basis.
In order to properly examine their association, we make a statistical analysis of PsA and chorus waves from 2017 to the present during which simultaneous conjugate observations were achieved with the Arase satellite and multi-point ground instruments. The conditions were as follows: 1) Arase was located at higher than 10º, 2) No loss of satellite mapping data, and 3) Optical determination of auroras (i.e., diffuse auroras, amorphous pulsating auroras, and patchy pulsating auroras) is possible in the vicinity of Arase. 64 nights, 141 hours of conjunctions were found, with a total duration of 25.5 hours for the events selected for this study. In this presentation, we report details of the analysis method, observed data, correspondence between high-latitude chorus waves and PsA types, and some initial results on the electron density variation in the magnetosphere.
In order to properly examine their association, we make a statistical analysis of PsA and chorus waves from 2017 to the present during which simultaneous conjugate observations were achieved with the Arase satellite and multi-point ground instruments. The conditions were as follows: 1) Arase was located at higher than 10º, 2) No loss of satellite mapping data, and 3) Optical determination of auroras (i.e., diffuse auroras, amorphous pulsating auroras, and patchy pulsating auroras) is possible in the vicinity of Arase. 64 nights, 141 hours of conjunctions were found, with a total duration of 25.5 hours for the events selected for this study. In this presentation, we report details of the analysis method, observed data, correspondence between high-latitude chorus waves and PsA types, and some initial results on the electron density variation in the magnetosphere.