Numerical simulation of ionospheric storms

Numerical modelling of ionospheric storms in April 1973 has been made within the framework of a model of neutral atmosphere. The calculations were carried out by numerical integration of continuity equations for NO+, O2+, and O+ of the equations of thermal balance for O+ electrons and ions and of the equations of motion for meridional and zonal components of velocity of thermospheric winds. Time changes of ionozphere and thermosphere parameters (during the period from 31.03 till 3.04 1972) as well as high-altitudes profiles of electron concentration and temperature for day and night conditions on 2.04 1973 are given. It is shown that, when there is a high magnetic activity it is impossible to attribute observed reductions of electron concentration only to changes in neutral composition because of counteracting effect of thermospheric winds. As an additional mechanism it is necessary to attract ionosphere heating from above at the expense of thermal conductivity from protonosphere and take account of oscillatory excitation of N2 molecules with electron shock