Paper#: 95
Poster #: 17
Session Name: Poster Session 1
Room: East Ballroom
Day: Tuesday
Time: 10:10 a.m.-Noon
Abstract Title: Energetic Electron Plashs Before the Main Substorm Injection
PresentSurname: Kozelov, B.V.
All Authors: T.V. Kozelova, L.L. Lazutin , B.V. Kozelov
Abstract : Sudden increases of particle fluxes (injections) during substorm in the magnetosphere are the signature of particle acceleration and are the subject of intensive study. However, plashs of particles occurring sometimes before the main injection are not fully investigated. We examine here transient (15 - 30 s) plashs of energetic electron > 21.5 keV (with time resolution < 1s) observed before the main injections on the CRRES. We found that the highest increases of electron fluxes are observed within the range of PA ~ 60-120 deg. (electron acceleration perpendicular to the magnetic field) near the inner edge of the plasma sheet. Near the outer boundary of trapped energetic particle region, the earthward field-aligned fluxes and isotropic fluxes within the range of PA ~ 40-170 deg. were observed. The electron plash onsets correlate with the rapid transient enhancement of magnetic field during ~ 2-4 s. It is likely that particles are accelerated by induced E field arising from these (dBz/dt)- bursts of magnetic field. The (dBz/dt) bursts co-exist with more large scale time-dependent variations of magnetic field: dipolarization (~1 min), impulse of Bz component (~30 s) or oscillations (~50 s). These more large scale processes can lead to additional particle energization through the induced E fields arising from this global field reconfiguration. The work is supported by grant RFBR-01-05-64827-a.