Configuration of the magnetosphere-ionosphere convection system under northward IMF conditions with nonzero IMF By

Abstract

The configuration of the magnetosphere-ionosphere convection system is investigated by analyzing outputs of a global magnetohydrodynamic (MHD) model for the solar wind-magnetosphere-ionosphere (S-M-I) coupling process. The input interplanetary magnetic field (IMF) to the model is inclined 45° from the due-northward direction with downward IMF. The results clearly show that the round cell and crescent cell are formed in the polar ionosphere and that the lobe cell and merging cell in the magnetosphere are connected to the core of the round cell and to the outer round and crescent cells, respectively. The open field lines that construct the lobe-cell circulation are generated through the open-field-line reconnection on the poleward side of the cusp, together with unconnected field lines. The open magnetic field lines that extend from the outer round cell in the Northern (Southern) Hemisphere and construct the merging-cell convection are generated through the closed-field-line reconnection in the Northern (Southern) Hemisphere, while the open magnetic field lines that extend from the crescent cell in the Northern (Southern) Hemisphere are generated in the Southern (Northern) Hemisphere. Convecting through the lobe, the open field lines from the northern outer round cell reconnect with the open field lines from the southern crescent cell in the northeast edge of the twisted plasma sheet. The features of the merging-cell convection can become very complicated in the plasma sheet. Copyright 1999 by the American Geophysical Union.