Response of the Ionospheric Convection Reversal and Associated Plasma Motions to Changes in the IMF

Abstract:

Systematic observations of the high latitude ionospheric plasma motion reveal that when a two-cell convection pattern can be identified the interplaneary magnetic field (IMF) has a significant influence on the location of the convection reversal boundary. We present results from a study of data from the DMSP F13 and F15 satellites over the period from 2000 to 2007, that describe the location of the reversal boundary, the general plasma motion with respect to it, and how it is reconfigured by changes in B_y and B_z. The data suggest that: (1) changes in B_y and B_z are equally effective in producing reversal boundary motions and the boundary moves more prominently on the dawnside or duskside dependent on the sign of B_y, (2) in general the boundary is not well described by a circle that is usually considered in an expanding/contracting polar cap paradigm, (3) plasma flows across the boundary in the 6-7 and 17-18 LT sectors are very small and may be attributed to the viscous interaction during stable IMF periods, and (4) equatorward motions of the boundary and the plasma are most often seen at the highest latitude locations and poleward motions of the boundary and the plasma are most often seen at the lowest latitude locations.