Solar zenith angle and solar activity dependences of vertical profile of electron number density in the nightside auroral region

概要

論文の詳細を見る
Solar zenith angle and solar activity dependences of electron number density in the nightside auroral region from the topside ionosphere to the magnetosphere within a geocentric radial distance of 2.6 R_E were statistically investigated based on analysis of 7-years of plasma wave data measured by the plasma wave instrument onboard the Akebono (EXOS-D) satellite. The results are summarized as follows: (1) Electron number density N_e changes depending on solar zenith angle and solar activity: N_e in sunlight is about 3 times larger than that in darkness, and N_e during solar maximum is about 10 times larger than that during solar minimum. (2) During solar maximum, geopotential scale height is almost constant within a range from 250km to 400km. During solar minimum, geopotential scale height is drastically changes at a geopotential height around 2000-2500km, or an actual height of 3000-4000km: Geopotential scale height is 250-400km below the transition height and larger than 500km above the transition height. In order to discuss the auroral phenomena in various seasonal and solar activity conditions, the variations of ambient electron number density, as obviously shown in this study, should be taken into consideration in future studies.
国立極地研究所の論文