[P-EM11] New frontier: Observations of the middle and upper atmospheres from ISS

[PEM11-16] 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、山崎 敦²、村上 豪²、吉川 一朗³ (1.京都大学大学院理学研究科地球物理学教室、2.宇宙航空研究開発機構　宇宙科学研究所、3.東京大学)

キーワード：上部電離層, ヘリウムイオン

Horizontal structures of ionised 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 HeII radiation (30.4 nm) from the International Space Station (ISS) since October 2012. North-south asymmetry and longitudinal structure of ionised Helium were found. North-south asymmetry in solstice seasons is well consistent with the 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.