On the origin of electric fields in the plasmasphere

Whistler data recorded continuously at Sanae, Antarctica (L=4) over a 24 hour period of quiet magnetic conditions (average Kp=1) have been analysed to obtain plasma convection patterns. A duskside plasmaspheric bulge is present, centered on 1700 UT. The westward electric fields determined for this bulge region suggest that quiet time plasma drift is predominantly controlled by internal ionospheric current systems of dynamo origin, while in a limited local time sector there is some evidence of the magnetospheric dawn-to-dusk electric field being responsible