The Storm Time Evolution of the Ionospheric Disturbance Plasma Drifts

Abstract

In this paper, we use the C/NOFS and ROCSAT-1 satellites observations to analyze the storm time evolution of the disturbance plasma drifts in a 24 h local time scale during three magnetic storms driven by long-lasting southward IMF Bz. The disturbance plasma drifts during the three storms present some common features in the periods dominated by the disturbance dynamo. The newly formed disturbance plasma drifts are upward and westward at night, and downward and eastward during daytime. Further, the disturbance plasma drifts are gradually evolved to present significant local time shifts. The westward disturbance plasma drifts gradually migrate from nightside to dayside. Meanwhile, the dayside downward disturbance plasma drifts become enhanced and shift to later local time. The local time shifts in disturbance plasma drifts are suggested to be mainly attributed to the evolution of the disturbance winds. The strong disturbance winds arisen around midnight can constantly corotate to later local time. At dayside the westward and equatorward disturbance winds can drive the F region dynamo to produce the poleward and westward polarization electric fields (or the westward and downward disturbance drifts). The present results indicate that the disturbance winds corotated to later local time can affect the local time features of the disturbance dynamo electric field.