Responses of Ionospheric F layer Radial Current to the Enhanced Solar Wind Input

Using Challenging Minisatellite Payload and the Republic of China Satellite-1 observations, the response of ionospheric radial current (IRC) in the F region to the enhancement of merging electric field (E_m) at different magnetic local times (MLT) is investigated. Possible physical mechanisms are discussed in terms of neutral wind, conductivity, and prompt penetration electric field (PPEF). The disturbance IRC (ΔIRC) increases in the upward (downward) direction in the daytime (nighttime) within 3 h after E_m enhancement. However, disturbance zonal winds increase westward (eastward) at 12–18 MLT (00–06 MLT). The reduced F region electron density may help weaken IRC at 06–12 MLT and 18–24 MLT. This work indicates that the daytime eastward (nighttime westward) PPEF drives equatorward (poleward) Hall current at low latitudes, resulting in both upward (downward) ΔIRC and eastward (westward) plasma drift at the F region magnetic equator.