NASA NTRS1980
Plasma convection patterns in the high-latitude F region are examined, and their implications for F region plasma distributions and the magnetosphere-solar wind interaction are discussed. In-situ electric field measurements in the ionospheric plasma above invariant latitudes of 60 deg are presented which show that the dominant plasma motion is one of two-cell convection perpendicular to the magnetic field, with motion directed away from the sun at invariant latitudes above 70-75 deg and return flow at lower latitudes. AE-C data revealing the presence of eastward, rather than antisunward, convection in the polar cap region is also noted. Analysis of the F region plasma distributions that may result from the two convection patterns indicates that total ion concentrations may differ by two or three orders of magnitude in different signatures of the high-latitude F region, and may account for the mid-latitude F region trough. The F region patterns are also shown to imply that in an open magnetosphere, a region of reconnection extends across a substantial portion of the magnetotail, while in a closed magnetosphere, the viscous interaction may weaken as the plasma moves down the tail, or remain strong with the boundary layer extending down the tail. The importance of further measurements of the stability of the F region convection pattern is pointed out.