Recent advances in studies of magnetosphere-ionosphere coupling.

This paper highlights some of the studies carried out over the last two years (1983-85) in the field of magnetosphere-ionosphere coupling. Our understanding of the physical processes in the coupling system has increased in the following respects: 1. Global simulation models have started to attempt to include several crucial ionospheric and magnetospheric parameters self-consistently. 2. Understanding of the high-latitude electric field pattern has been significantly upgraded. Convection models for different interplanetary magnetic field (IMF) orientations have been developed. 3. While magnetospheric substorms continue to attract attention, studies have also been devoted to the state of the magnetosphere-ionosphere system for northward IMF. 4. Combined data sets and simulation models have been brought to bear on the problem of the westward traveling surge and the Harang discontinuity. 5. Considerable attempts have been made to determine scale lengths of the V-shaped potential structure. 6. Recent satellite observations have centered on the role of ionospheric ions and magnetospheric electrons that are accelerated through the potential structure. 7. We now understand that enhancements in auroral conductance facilitate the degree of penetration of the convection electric field into the inner magnetosphere. 8. Recent technical innovations include use of multiple radar techniques to sense the electrodynamic properties of the ionosphere coupled with the magnetosphere.