资源环境科技发展态势分析平台

We present Super Dual Auroral Radar Network observations of ionospheric convection during substorms. Substorms were grouped according to their onset latitude, onset magnetic local time, and the prevailing sense of interplanetary magnetic field (IMF) B-Y. The radar observations were then sorted according to substorm group and average convection patterns produced. Here we discuss the patterns corresponding to substorms with onsets occurring in the 65 degrees-67 degrees onset latitude range, at either early (20-22 h) or late (01-03 h) magnetic local times, during intervals of either dominant positive or negative IMF B-Y. We show that the morphology of the convection patterns differs from that predicted by existing empirical models, with the location of the nightside convection throat being largely consistent with the location of substorm onset. The expected IMF B-Y-induced dawn-dusk convection asymmetry can be enhanced on the nightside when the substorm onset occurs at a fortuitous location but can equally be removed or even reversed from this expected state. Thus, the nightside convection asymmetries are seemingly unrelated to the instantaneous sense of IMF B-Y.