The timing relationship between bursty bulk flows and Pi2s at the geosynchronous orbit

Abstract

The present study observationally examines relationship between Pi2 pulsations and the bursty bulk flow (BBF) in the plasma sheet. At a Pi2 onset of August 14, 1996, the GEOTAIL satellite and the GOES8 geosynchronous satellite were aligned in the X direction observing transient signatures. Those signatures were examined by referring to a ground low-latitude Pi2 wave detected at the same meridian as GOES8. In the present event, a BBF started prior to the ground Pi2 onset, but it was preceded by a Pi2 onset at GOES8. It is also found that ground Pi2 signatures were correlated much better with geosynchronous Pi2 signatures than with perturbations of the plasma sheet flow velocity measured at GEOTAIL. These results strongly suggest that the BBF was not the cause of the low-latitude Pi2 observed in the present event.