[P-EM16] 大気圏・電離圏

[PEM16-P20] ISS-IMAP/EUVIで観測された夕方側電離圏上部Heイオンの水平構造

*穂積 裕太¹、齊藤 昭則¹、吉川 一朗²、山崎 敦³、村上 豪³ (1.京都大学大学院理学研究科、2.東京大学、3.宇宙航空研究開発機構　宇宙科学研究所)

Horizontal structures of ionized Helium in the upper ionosphere of dusk side were obtained from observation of resonant scattering light. The Extreme Ultra Violet Imager (EUVI) of the ISS-IMAP (Ionosphere, Mesosphere, upper Atmosphere and Plasmasphere mapping) mission has taken image of He II radiation (30.4 nm) from the International Space Station (ISS) since October 2012. North-south asymmetry and longitudinal structure of ionized Helium were found. North-south asymmetry in solstice seasons are well consistent with previous in-situ measurement and numerical simulation. However, the longitudinal structure is not reported before and cannot be explained by numerical simulation with SAMI2-model. The longitudinal difference of meridional wind is a candidate of the Helium ion structure.