Computer simulation of electron and ion densities and temperatures in the equatorial F region and comparison with Hinotori results

Abstract

A time‐dependent three‐dimensional computer simulation of equatorial F region ionosphere has been carried out to understand the electron temperature structure observed by Hinotori satellite in the low and middle ionosphere. This model provides three‐dimensional distributions of ion densities, electron temperature, and ion temperatures. The simulations showed the electron temperature enhancements around the equator in the morning, in the midlatitude in the afternoon, and around the equatorial anomaly region from afternoon to midnight. The enhancements in the morning are due to photoelectron heating. The afternoon enhancements in the midlatitude come from the balance of heating and cooling. When no meridional neutral wind is included in the simulation, the electron temperature did not show remarkable enhancements in the midlatitude in the afternoon because of strong cooling by the dense electron density. Around the equatorial anomaly region the electron temperature increased at high altitude in the evening because of the competing effects of plasma cooling and the plasma movements. Since the ionospheric plasma zonal E×B drift is eastward near the sunset (where E is ionospheric electric field and B is magnetic field) and the vertical drift is downward, the high‐altitude dayside hot plasma can enter into the topside F region in the premidnight. The computer simulations were directly compared with the Hinotori satellite data. The simulation results were consistent with the equatorial electron density and temperature observed by the Hinotori satellite.