Observations of plasma entry into the magnetosphere at late magnetic local times Original Research Article

After the plasma cloud from a coronal mass ejection had passed the Earth on January 11, 1997, the Interball-2 satellite observed several consecutive dispersion ramps of magnetosheath protons above the evening sector auroral region. These protons were encountered at high magnetic latitudes over a wide local time sector, closer to midnight than has been previously reported. At the time of observations the IMF was strongly northward and the polar cap was highly contracted. Simultaneous observations from Interball-2, Polar, and SuperDARN indicate that magnetosheath plasma was observed in the region of sunward convection, and had most likely entered the magnetosphere either through the evening sector flank magnetopause or in the tail. The characteristics of the dispersion ramps suggest that they were caused by several temporally limited injections through a spatially wide area.