Time history effects at the magnetopause: Hysteresis in power input and its implications to substorm processes

The energy input processes through the magnetopause are examined in the GUMICS-4 global MHD simulation. We demonstrate that the energy input through magnetopause is strongly controlled by the IMF clock angle, but also on the previous level of magnetic activity. This hysteresis ap pears in a variety of model runs, and seems to originate from the nature of magnetopause reconnection. These results are shown to imply that the substorm energetics is directly driven by the incoming energy. Based on these results, the differences between the substorm dynamics and substorm energetics are discussed.