Multipoint observations of dipolarization front formation by magnetotail reconnection

We present multipoint observations of magnetotail plasma sheet dynamics during an event in which magnetic reconnection and dipolarization were observed at -16 < X < -15 R-E (mid-tail) and at -10 < X < -4.8 R-E (near-Earth plasma sheet), respectively. Timing analysis of the observations shows that the near-Earth dipolarization was a consequence of mid-tail reconnection. Large-amplitude magnetic field oscillations were observed in the temporal and spatial vicinity of the reconnection site. Interpreted as current sheet flapping, they enable reconstruction of a complex sheet structure with an embedded thin current sheet of ion inertial scale size. Detailed analysis of the orientation of the dipolarization front and of plasma motions around it reveals that the front of the reconnection jet was interchange unstable.