Theoretical study of the seasonal behavior of the global ionosphere at solar maximum

The seasonal behavior of the global ionosphere was studied using a time-dependent three-dimensional physical model (developed by Shunk and his coworkers) of the ionosphere at altitudes between 120 and 800 km. This model accounts for field-aligned diffusion, cross-field electrodynamic drifts both the equatorial region and at high latitudes, interhemispheric flow, thermospheric winds, polar wind escape, energy-dependent chemical reactions, neutral composition changes, ion production due to solar EUV radiation and auroral precipitation, thermal conduction, diffusion-thermal heat flow, and local heating and cooling processes. The model studies were carried out for both June and December solstice conditions at solar maximum and for low geomagnetic activity. The ionospheric features predicted by the model agreed qualitatively with the available measurements.