[P-EM28_29PM2] 磁気圏-電離圏結合

[PEM28-15] カスプにおけるオーロラ増光の時間空間分布

*田口 聡¹、細川 敬祐¹、小川 泰信² (1.電気通信大学、2.国立極地研究所)

キーワード：オーロラ, カスプ, 粒子降下, 磁気リコネクション, 全天イメージャ

Previous studies have shown that mesoscale auroral forms occur near the equatorward edge of the background, stable cusp aurora, and that they move in a direction that is consistent with the motion of the magnetic field line after reconnection on the dayside magnetopause. In this study we pay attention to its initial brightening using data from a high-sensitivity all-sky imager at Longyearbyen, Svalbard. The imager has a field-of-view that spans more than 4 hours in MLT, and can observe auroral brightenings that are widely separated in MLT. We determined the position of dayside auroral brightening using the 630-nm auroral images, and examined how these positions are distributed in the cusp, focusing on intervals when IMF was extremely stable. Results of analyses show that brightening occurs over a wide dayside MLT range. We show detailed spatiotemporal patterns for successive brightening events, and discuss the patterns in terms of the formation of intermittent reconnection on the dayside magnetopause.