Magnetopause coupling processes and ionospheric responses: a theoretical perspective

In recent years much progress has been made in establishing the mechanisms for mass, momentum and energy transfer from the solar wind into the terrestrial magnetosphere; in particular, the importance of reconnection, at least at disturbed times, is generally agreed. In the simplest circumstances, where dayside and nightside reconnection rates are balanced and steady, the simple open magnetospheric model would pertain. In general, however, reconnection is unsteady, day-night flux transfer occurs in an irregular way and the full complexity of the solar-wind-magnetosphere-ionosphere system becomes apparent. A hierarchy of coupling times, for each of which different processes dominate, needs to be considered. (author)