Whistle and Hall magnetic field associated with near-Earth magnetotail reconnection observed by Cluster

During 2001-2003, the Cluster spacecraft passed through the near-Earth magnetotail, and observed 14 magnetotail reconnection events. Simultaneously, Cluster observed electromagnetic wave associated with reconnection events. There are three kinds of reconnection events in these 14 events. There are 8 events in the first kind of reconnection event, in this kind of reconnection events wave activity were observed prior to the reconnection event and simultaneously Hall magnetic field was observed. The wave activity included right hand polarized Whistler. The second kind of reconnection events had two events. Whistler waves and Hall magnetic field were observed in this kind of events, but the wave activity was not prior to reconnection events. The third kind of events had two events. The Whistler waves and Hall magnetic were not observed in this kind of reconnection event. In these 14 events, the strong Whistler waves corresponded to Hall magnetic field. Whistler waves may mainly be excited in Hall magnetic field regions.