The auroral signature of earthward flow bursts observed in the magnetotail

Abstract

We present direct evidence that transient Earthward flow bursts in the magnetotail can produce an observable signature in the optical aurora. This signature is north‐south aligned auroral structures that are extensions of transient intensifications near the poleward boundary of the auroral oval. Our study focuses on the period from 0500 to 0700 UT on January 7, 1997, during which five distinct flow bursts are observed in the Geotail data. At that time, the spacecraft was located approximately 30 R E downtail on field lines that project down to the CANOPUS array of ground based instruments. We find that each of the flow bursts seen in the Geotail data is associated with an auroral poleward boundary intensification (PBI) observed in the CANOPUS meridian scanning photometer (MSP) data, which appears as a north‐south aligned auroral structure in the CANOPUS all‐sky imager (ASI) data. Based on these observations we estimate that the fast flows originated between 50 and 100 R E downtail.