Modelling high-latitude ionosphere for time-varying plasma convection

The author discusses how variations in the pattern of convective plasma flows should be included in self-consistent time-dependent models of the coupled ionosphere-thermosphere system. The author shows how these variations depend upon the mechanism by which the solar wind flow excites the convection. The modelling of these effects is not just of relevance to the polar ionosphere. This is because the influence of convection is not confined to high latitudes: the resultant heating and composition changes in the thermosphere are communicated to lower latitudes by the winds which are also greatly modified by the plasma convection. These thermospheric changes alter the global distribution of plasma by modulating the rates of the chemical reactions which are responsible for the loss of plasma. Hence the modelling of these high-latitude processes is of relevance to the design and operation of HF communication, radar and navigation systems worldwide