Is BBF Exciting the Current Sheet Flapping Near Earth Magnetotail?

Abstract:

The flapping current sheet is observed frequently in the magnetotail. Some times, the BBF and flapping current sheet are observed by spacecraft simultaneously. But some flapping current sheets case is not associated with BBF. Some study show BBF excited the flapping current sheet. The simulation result show the ion flow has the vorticity during the period of flapping wave. Our observation show after a reconnection event observed, a typicle flapping current sheet event is observed associated periodic bursty bulk flows. The flapping wave period is two minutes. The bust of speed ion flow and the flapping current sheet are with the same period. The current J_xand J_y also have period peak. The periodic variation is accompanied by simultanesous in-phase periodic oscillation of the Bx and By component. Ion and electron flux also oscillates with the same period of B_x and B_y. The observation show that during one cycle of flapping current sheet, the ion flows has the vorticity, which is consistent with the simulation results. But, during the reconnection event, the ion flows have not the vorticity. This result show the source of the ion flows during the reconnection event and the flapping event is not the same. The flapping current sheet motion generates the ion vorticity motion.