Global observations of energetic electrons around the time of a substorm on 27 August 2001

Abstract

The magnetospheric substorm that occurred shortly after 04:00 UT on 27 August 2001 has been a topic of detailed study (Baker et al., 2002; Li et al., 2003). These studies included analysis of data from energetic electron detectors aboard the Cluster and Polar spacecraft that were located in the magnetotail during the substorm. Serendipitously, Chandra, the X-ray observatory, also carrying an energetic electron detector, was located in the magnetotail several hours earlier in local time. Examination of data from the three magnetotail positions revealed that enegetic electrons (>35 keV) appeared simultaneously at all three locations, and that the appearance was ten minutes after the injection into geostationary orbit (GEO) as determine by examination of drift dispersion at several local times in GEO orbit. In addition to the substorm-associated electrons, time-correlated electron bursts were observed by the magnetotail spacecraft for a few hours prior to the substorm.