On the Reversal from “Sunward” to “Antisunward” Plasma Convection in the Dayside High Latitude Ionosphere

Preliminary observations of dayside high latitude ionospheric plasma convection with the Sondrestrom incoherent-scatter adar indicate that plasma can be observed to enter the polar cap region through rotational reversals at most local times between dawn and dusk and not just in a narrow region around noon. Assuming that rotational reversals are signatures of a solar wind-magnetosphere interaction which drives magnetospheric convection, the observations indicate that this interaction occurs over a longitudinally wide area of the dayside magnetosphere. The observations also show that the distribution of F-region plasma in the polar cap is dependent on ionization sources anywhere between dawn and dusk in the dayside high latitude ionosphere.