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Zusammenfassung:
This study presents a systematic analysis of ion flow, and accompanying electric and magnetic fields, from the Space Weather Modeling Framework (SWMF). Inside of 10 R_E the flow speeds are typically under 50 km/s during quiet and moderate driving conditions, but fast flows well in excess of 100 km/s regularly develop during the main phase of storm intervals. In particular, a strong sunward flow is seen in the simulation results, at various places in the near-Earth tail region and near the terminator plane, between 5 and 12 R_E. These regions (extending from the nightside around both dawn and dusk flanks) can have persistent flows over 200 km/s, confined near the equatorial plane and with local electric fields in excess of 10 mV/m. They seem to be fairly persistent and exist in regions of low plasma pressure; the inclusion or exclusion of an inner magnetospheric drift physics model does not significantly alter there timing, location, or intensity. As the driving diminishes, so do these fast flows. The field lines are clearly not electric equipotentials during these intervals, with a peak electric field at the equatorial plane (rather than the ionosphere, as equipotential mapping would dictate). The features and physics of these fast flows are presented and discussed. Comparisons are made against flow and field measurements from various spacecraft, like the Van Allen Probes, GOES, THEMIS, and MMS, showing that, occasionally, signatures like this flow feature exist in the data, but not on such a regular basis as in the code results.
