[P-EM14] [EE] Dynamics in magnetosphere and ionosphere

[PEM14-P33] EMCCDカメラによる脈動オーロラ変調特性の観測

*浅野 貴紀¹、三好 由純¹、栗田 怜¹、大山 伸一郎¹、細川 敬祐²、小川 泰信³、西山 尚典³、町田 忍¹ (1.名古屋大学宇宙地球環境研究所、2.電気通信大学大学院情報理工学研究科、3.国立極地研究所)

キーワード：aurora

Pulsating aurora (PsA) shows quasi-periodic intensity modulation with a 2 s to 30 s intervals as a main modulation. PsA is mainly observed from the post-midnight to the morning sectors during the recovery phase of substorms. PsA consists of not only main modulations but also internal modulation with a few Hz. We installed multi-EMCCD cameras in Tromso, Finland, Sodankyla, Kevo Finland and Alaska, US. The cameras with RG665 filters observe high-speed phenomena with 100 Hz sampling rate, while the cameras with different filters observe spectrum of PsA with 10 Hz sampling rate. In order to investigate spatio-temporal characteristics of the main modulations as well as internal modulations, we apply PCA (Principal Component Analysis) and FFT to all-sky images of PsA with 100 Hz sampling rate. PCA decomposes into different modes with periods of a few seconds, indicating that localized structure of the main modulation of PsA. The all-sky images at different frequency derived from FFT show that the spatial distribution of PsA depends on the frequency and the internal modulations with high frequency appear in a part of the main modulations. In this presentation, we will report statistical results on these spatio-temporal characteristics of PsA.