Statistical survey of dispersionless substorm injections observed by the CRRES MICS ion spectrometer

We have used medium energy (40-400keV) ion data from the MICS instrument flown on the CRRES spacecraft during the first half of 1991 to identify and study the distribution of approximately 90 dispersionless sub-storm injection signatures. During this period the geostationary transfer orbit of CRRES provided good sampling for local times from 18:00 through to 02:00, and L-Shells between 4 and 8. Each signature has been classified in terms of its type (single or multiple), composition (Ionospheric or solar wind rich) and prevailing magnetospheric conditions (represented by Dst). The resulting database has been used to investigate the dependencies of these parameters on each other and, after correction for S/C sampling effects on the observed spatial distribution of the events.