HR: 0800h
AN: SA21A-0293    [Abstracts]
TI: The Influence Of Substorm-Induced Electric Fields On The Build-up Of Particle Radiation During Geospace Magnetic Storms
AU: * Metallinou, A F
EM: ametal@astro.auth.gr
AF: Aristotle University of Thessaloniki, Department of Physics, Section of Astrophysics, Astronomy and Mechanics, Thessaloniki, 54124 Greece
AU: * Metallinou, A F
EM: ametal@astro.auth.gr
AF: National Observatory of Athens, Institute for Space Applications and Remote Sensing, Penteli, Athens, 152 36 Greece
AU: Daglis, I A
EM: daglis@space.noa.gr
AF: National Observatory of Athens, Institute for Space Applications and Remote Sensing, Penteli, Athens, 152 36 Greece
AU: Delcourt, D C
EM: dominique.delcourt@cetp.ipsl.fr
AF: Centre d'Etude des Environnements Terrestre et Planetaires, CNRS-Observatoire de Saint-Maur,4, avenue de Neptune, Paris, 94107 France
AB: The enhanced magnetospheric convection electric field and the substorm-induced electric fields are the drivers of plasma acceleration during geospace magnetic storms. The relative influence of the two drivers on the development of the storm-time ring current is the topic of this study. We use a three-dimensional dynamic ion-tracing model, to construct maps of the temporal and spatial variations of ion number densities in the inner magnetosphere. Outflowing ionospheric oxygen ions and protons are traced under two distinct scenarios: in the first case, we follow their transport and acceleration under the influence of a large convection electric field only. In the second case, an impulsive electric field is added due to magnetic field dipolarization, as observed by spacecraft during substorm expansion. Plasma sheet particles are also traced under the above conditions. According to this study the inclusion of substorm-induced electric fields renders ion acceleration much more efficiently. The difference in energization is much more prominent for O+ ions, which have been observed to be preferentially accelerated by substorm-induced electric fields. For both ion species large-scale magnetospheric convection alone is not sufficient to accelerate these particles to ring current energies.
DE: 7954 Magnetic storms (2788)
SC: SPA-Aeronomy [SA]
MN: Fall Meeting 2005