Solar wind control of electric fields and currents in the magnetosphere and ionosphere

Solar wind-magnetosphere/ionosphere interactions were examined during the International Magnetospheric Study. Permanent field-aligned currents with a steady antisunward polar cap convection are due to steady generation of electric currents in the low-latitude boundary layer and at the boundary of the plasma layer during viscous-like solar wind during magnetosphere interaction. Merging of the interplanetary magnetic field (IMF) with geomagnetism causes growth of the polar cap size and symmetric enhancement of the antisunward convection across the polar cap in the presence of a southward IMF component, and a corresponding increase of the potential drop across the polar cap. It also causes polar cap contraction, asymmetric enhancement of antisunward convection, and displacement of the polar cap along the dawn-dusk meridian.