The magnetotail current sheet movement detected by Cluster

Using Cluster four spacecraft data, we have made a statistical research on the motion properties of the magnetotail current sheets of the year 2004 and 2005 with various methods. We find that most of the current sheets are propagating from the midnight tail region to dawn and dusk flanks which is consistent with previous studies. Most of the current sheets are propagating with the velocities smaller than 100 km/s, and the exceptions account for 6.5 % of all events. We have also found that `Enter/Retreat´ current sheets more favorably occur during the southward interplanetary magnetic field (IMF).