Wednesday

The Interplanetary Magnetic Field (IMF) By component can have a profound effect on the asymmetry of the solar wind-magnetosphere coupling by introducing a ‘twisted’ magnetotail configuration, giving closed magnetotail field lines an induced By component. In this paper, we discuss and analyse the link between magnetotail fast flows, from data taken by Cluster, and concurrent ionospheric flow bursts measured by SuperDARN, in an attempt to understand better their azimuthal asymmetry. We identify 604 fast flow events in the tail plasma sheet, from Cluster data between 2001-2014. We filter our event list to only include events that explicitly imply a dawn-dusk flow asymmetry in the magnetotail, e.g. dawnward flow observed duskward of midnight. We then look at the statistical correlation between these localised flows in the tail and the larger-scale magnetospheric morphology as inferred from the upstream IMF orientation and concurrent ionospheric flow patterns. Our results indicate a complicated picture with the dawn-dusk sense of the flows in the magnetotail disagreeing with the direction of the large-scale convection pattern in many cases. Furthermore, for events where radar data reveal a large-scale asymmetry, the convection pattern only seems to agree with the sense of the IMF By ~70% of the time. We apply different filtering thresholds to see how agreement with the expected flow direction varies, finding the best improvement when specifying that the local sense of By measured by Cluster in the Tail indicates a consistent twist (by comparing to the IMF By=0 T96 modelled tail magnetic field at Cluster’s location).