Restructuring of Nightside Convection During Substorm

Several features in the nightside convection patterns near the substrom onset time have been reported in the past. In this presentation, concurrent SuperDARN observations of plasma convection and IMAGE satellite data on global distribution of auroral luminosity are used to illustrate several effects in the convection patterns. For example, we show appearance of large-scale vortices in the dusk and dawn sectors near the onset time, their evolution and subsequent setup of enhanced plasma flows at the equatorward edge of the return dusk flows. Another focus of the study is the timing of the equatorward convection enhancements with respect to the substorm onset time.