ON THE ROTATION OF THE POLAR-CAP POTENTIAL PATTERN AND ASSOCIATED POLAR PHENOMENA

Geomagnetic and radar observations indicate that the potential and convection pattern in the northern polar cap are significantly rotated clockwise with respect to the noon-midnight meridian. On the basis of simple models, some of the basic roles of the highly conductive belt (the auroral oval) on the rotation was examined. It is shown that it develops a space charge distribution along the boundaries in such a way as to rotate the potential pattern clockwise. The rotation angle was estimated as a function of the ratio of the conductivity in the auroral oval to that in the polar cap for a given set of conditions for an assumed conductivity ratio.