A study of global structures of the ionosphere by modelling methods

Diurnal variations of the thermosphere and the ionosphere are calculated by solving simultaneous time-dependent continuity equations for O(+), H(+), O2(+), and NO(+) ions, equations of motions for ions and neutrals, the heat conduction equations for electrons and ions, and photoelectron transport equations. Equations are solved in the region from 120 km altitude to the equatorial plane along the field line, therefore coupling processes between the ionosphere and the protonosphere are fairly taken into account. In addition, micro-processes controlling the energy flow in the thermosphere are treated precisely to evaluate the heating efficiency of EUV radiations. It is shown that the calculated results for the structure of the ionosphere based on MSIS (mass spectrometer and incoherent scatter data) atmospheric model show good agreements with observations.