14:15 〜 14:30
[PEM10-13] Characteristics of eastward expansion of substorm auroral bulge
キーワード：サブストーム、オーロラ
After the expansion phase onset of a substorm, auroral bulge expands poleward, westward, and eastward. Its westward expansion is characterized by the rapid westward motion of the Westward Traveling Surge (WTS) on the expanding front. On the other hand, diffuse and pulsating aurora, auroral torch, and Omega-band usually appear and embedded in the eastern part of the bulge, and a discrete aurora is expanding eastward around the poleward edge of the bulge. Such features are well-known and a large amount of studies on the evolution of the substorm bulge have been done so far. But number of studies on the mechanism of the eastward expansion of the bulge seems not so large, comparing with that of the WTS, although number of studies on the evolution of the torch, Omega-band, and pulsating aurora is relatively large. In this study, we will examine details of the evolution of the eastward expansion of bulge at the eastward expanding front by using ground-based observations at Syowa Station, Antarctica.