Multi-point observation of the high-speed flows in the plasma sheet

The structure of the high-speed flows in the midtail plasma sheet is discussed based on results from multi-point observation of Cluster spacecraft in summer 2001 and 2002. The average rate of change in flow speed along the “dawn-dusk” direction (perpendicular to the main flow and in the plane of the tail current sheet) and along the “north-south” direction suggests that the full width of the flow channel is 12,000-17,000 km in the “dawn-dusk” direction and about 9000-12,000 km in the “north-south” direction. This is consistent with the results obtained from the analysis of the dipolarization front of the flows. The profile of the gradient of the flow in the north-south direction and the shape of the dipolarization front suggest that the BBF has the shape of a localized flux tube.