SuperDARN observations of the Harang discontinuity during steady magnetospheric convection

We present a study of ionospheric convection patterns observed by the Super Dual Auroral Radar Network (SuperDARN) during two recent steady magnetospheric convection (SMC) events. Our analyses focus on the region near the electrically defined Harang discontinuity (HDE) and indicate, for the first time, that the HDE is often present during SMC events. In comparison with observations made during a typical substorm growth phase, the HDE during the two SMC events studied here is a less pronounced convection feature and often occurs at relatively high geomagnetic latitudes (>70°). In addition the behavior of the HDE during the substorms bounding the SMC events appears to differ from the classic signatures observed during isolated substorms.