Characteristics of Auroral Particles Observed by EXOS-C

抄録

The low-energy particle experiment (ESP) onboard the EXOS-C satellite has given us new information on characteristics of low-energy electrons and ions. Our observations of auroral electrons and ions are mostly consistent with the observational results obtained by others. However, some interesting characteristics of ions precipitating into the auroral region have also been found and discussed in this paper. 1) Three types of energy dispersions of ions in the noon sector were observed at different magnetic activities. The first is the increasing energy with increasing invariant latitude, the second is the decreasing energy, and the last is no energy dispersion. 2) Ions penetrating into the evening and midnight sectors could be divided into two patterns of the energy spectra. Ions in the energy range of 1 to 10keV are populous in the region of the diffuse electron precipitation, while the ion spectra harden in the discrete precipitation. 3) Intense precipitating or trapped ions were observed in the region of the diffuse electron precipitation of the morning sector.