Feasibility study of the O II 83.4-mm imaging of the inosphere and magnetosphere Original Research Article

Recent in-situ plasma observations find that large amounts of O+ are escaping from the terrestrial ionosphere to the magnetosphere. Remote-sensing methods using the extreme ultraviolet (EUV) emission of O+ have been expected to be a powerful tool to provide a global perspective on the escaping processes. The overall picture is also very important for the practical use such as monitoring space weather. O+ ions resonantly scatter the solar photons with wavelength 83.4 nm. The key to the success of the observation is to prevent from detecting the H Ly-α line (121.6 nm), which is stronger than the predicted O 11 emission by four orders of magnitude. We have successfully detected O II emission from the uppermost part of the ionosphere using the sounding rocket SS-520-2 to investigate heavy ion escape from the. cusp/cleft region. This success demonstrates the capability of the remote-sensing method to take an instantaneous 2-dimensional image of the O+ distribution, and provides a way for optical observation of the magnetosphere. We plan to obtain O II images of the polar wind using the Telescope for EXtreme ultraviolet light, which is an upgrade version of the instrument for the sounding rocket, in the Upper atmosphere and Plasma Imager component (UPI-TEX) on the SELenological and ENgineering Explorer (SELENE). We refer to the feasibility of the O 11 imagery from the lunar orbit satellite.