5:15 PM - 6:30 PM
[PEM16-P20] Horizontal structures of Helium ion in the upper ionosphere observed by ISS-IMAP/EUVI
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.