Development of auroral streamers in association with localized impulsive injections to the inner magnetotail

During continuous magnetospheric activity it is not uncommon to observe nar row (in MLT) transient particle injections (duration about 1-2 minute at E = 100 keV and local time extent less than or equal to 1 hour MLT) in the ni ghtside part of geosynchronous orbit. Using global UV images from POLAR spa cecraft we analyze the development of auroral activity on December 22, 1996 during a sequence of such injections observed by two LANL spacecraft. We f ound that narrow transient injections are associated with specific localize d auroral form, the auroral streamer, which develops in this local time sec tor. The streamer first appear as a bright spot in the poleward part of the double oval approximate to 2-5 minutes before the geosynchronous plasma in jection, and then develops equatorward, reaching in many cases the equatorw ard boundary of the UV aurora. We interprete the observations as evidence t hat some high speed flow bursts (BBFs) of small cross-tail extent (less tha n 1 h MLT), formed in the distant tail or midtail, can intrude as close to the Earth as the geosynchronous distance before being stopped.