... Electric field from solar wind/IMF system is mapped (either directly or via magnetosphere ) to the high-latitude ionosphere , creating horizontal E в B plasma drift called convection. ... In the simplest case, occurring during southward IMF, the F-region plasma flows antisunward over the polar caps (open field lines, i.e., solar wind regime), and returns sunward within the auroral oval (closed field lines, i.e., magnetospheric regime). ... Eather, R. H., Polar cusp dynamics, J. Geophys. ...