The pulsating auroral generation mechanism has been investigated by observing precipitating electrons using rockets or satellites. However, it is difficult for such observations to distinguish temporal changes from spatial ones. In this study, we reconstructed the horizontal 2-D distribution of precipitating electrons using only auroral images. The 3-D aurora structure was also reconstructed. We found that there were both spatial and temporal changes in the precipitating electron energy.

In this study, we present the comparison between an auroral model and EISCAT radar electron densities during pulsating aurorae. We test whether an overpassing satellite measurement of the average energy spectrum is a reasonable estimate for pulsating aurora electron precipitation. When patchy pulsating aurora is dominant in the morning sector, the overpass-averaged spectrum is found to be a reasonable estimate – but not when there is a mix of pulsating aurora types in the post-midnight sector.

Spatial structures of wave disturbances in the upper atmosphere were investigated with space-borne imaging from the International Space Station. The wave disturbance occurred around an altitude of 100 km, and is called a mesospheric bore. The large-scale structure of mesospheric bores has not been fully captured by previous ground-based imagers, but the space-borne imaging captured a bore with a wide field of view, and showed that bores can have a large undulating wave front as long as 2000 km.

Polar mesospheric clouds (PMCs) or noctilucent clouds (NLCs) are the highest clouds in the Earth's atmosphere. In this paper, we introduce new PMC observations by the Japanese Geostationary Earth Orbit (GEO) meteorological satellite Himawari-8, which was launched in October 2014.

Photo-electrons and secondary electrons from particle precipitation enhance the incoherent scatter plasma line to levels sufficient for detection. A plasma line gives an accurate measure of the electron density and can be used to estimate electron temperature. The occurrence of plasma line enhancements in the EISCAT Svalbard Radar data was investigated. During summer daytime hours the plasma line is detectable in up to 90 % of the data. In winter time the occurrence is a few percent.