Geotail observations of a fast tailward flow at X GSM = −15 R E

Abstract

Geotail observed a fast tailward flow burst (a speed of >600 km/s) with southward B z in the Earth's magnetotail at a radial distance of 15.5 R E on March 30, 1995. Ions in this burst consisted of a single‐component plasma showing convection motion, and these ions were confined near the neutral sheet. This flow burst was likely associated with a pseudobreakup rather than a major substorm onset. In this event, magnetic reconnection appeared to take place only for the field lines near the neutral sheet. The magnetic reconnection was quenched soon and resulted in a short‐lived tailward flow burst embedded in the plasma sheet.