[P-EM11] Dynamics of the Inner Magnetospheric System

[PEM11-06] Spatial relationship of SAPS and particle boundaries as observed by Arase

*堀 智昭¹、三好 由純¹、中村 紗都子¹、笠羽 康正²、中川 朋子³、北原 理弘¹、松田 昇也⁵、西谷 望¹、熊本 篤志²、土屋 史紀²、笠原 禎也⁴、浅村 和史⁵、Jun Chae-Woo¹、風間 洋一⁶、Wang Shiang-Yu⁶、桂華 邦裕⁷、笠原 慧⁷、横田 勝一郎⁸、松岡 彩子⁹、篠原 育⁵ (1.名古屋大学宇宙地球環境研究所、2.東北大学惑星プラズマ・大気研究センター、3.東北工業大学工学部情報通信工学科、4.金沢大学、5.宇宙航空研究開発機構宇宙科学研究所、6.台湾中央研究院、7.東京大学大学院理学系研究科地球惑星科学専攻、8.大阪大学理学研究科、9.京都大学 理学研究科 地磁気世界資料解析センター)

キーワード：SAPS、内部磁気圏、地球、電場

Relative displacement of subauroral polarization stream (SAPS) and particle boundaries in the inner magnetosphere is extensively investigated using the particle and field data obtained by the Arase satellite. The two major theoretical paradigms of SAPS, the current generator and the voltage generator models, both attribute the source of the poleward electric field (E-field) to a latitudinal (radial in the magnetosphere) gap between the ion and electron plasma sheets (PS). Indeed, the enhancement of electric field is frequently observed around the intermediate region between the two PS along inner magnetosphere passes of Arase in the evening-to-midnight sector. A close examination of the Arase observations, however, reveals that their relative position varies significantly from event to event: the radially-inner boundary of SAPS, for example, can form either in the intermediate region or at a further inward location of the PS gap. The plasmapause, as identified by the plasma wave observations, can appear either at the SAPS inner edge or at a further outward point. It is also found that most of the events show a broader radial width of SAPS E-field than the ion-electron PS gap. We discuss possible scenarios that can explain the variety of the spatial relationship of SAPS with both the PS and plasmapause.