MULTISATELLITE OBSERVATIONS OF THE OUTER ZONE ELECTRON VARIATION DURING THE NOVEMBER 3-4, 1993, MAGNETIC STORM

The disappearance and reappearance of outer zone energetic electrons d uring the November 3-4, 1993, magnetic storm is examined utilizing dat a from the Solar, Anomalous, and Magnetospheric Particle Explorer (SAM PEX), the Global Positioning System (GPS) series, and the Los Alamos N ational Laboratory (LANL) sensors onboard geosynchronous satellites. T he relativistic electron flux drops during the main phase of the magne tic storm in association with the large negative interplanetary B-z an d rapid solar wind pressure increase late on November 3. Outer zone el ectrons with E > 3 MeV measured by SAMPEX disappear for over 12 hours at the beginning of November 4. This represents a 3 orders of magnitud e decrease down to the cosmic ray background of the detector. GPS and LANL sensors show similar effects, confirming that the flux drop of th e energetic electrons occurs near the magnetic equator and at all pitc h angles. Enhanced electron precipitation was measured by SAMPEX at L greater than or equal to 3.5. The outer zone electron fluxes then reco ver and exceed prestorm levels within one day of the storm onset and t he inner boundary of the outer zone moves inward to smaller L (<3). Th ese multiple-satellite measurements provide a data set which is examin ed in detail and used to determine the mechanisms contributing to the loss and recovery of the outer zone electron flux. The loss of the inn er part of the outer zone electrons is partly due to the adiabatic eff ects associated with the decrease of Dst, while the loss of most of th e outer part (those electrons initially at L greater than or equal to 4.0) are due to either precipitation into the atmosphere or drift to t he magnetopause because of the strong compression of the magnetosphere by the solar wind. The recovery of the energetic electron flux is due to the adiabatic effects associated with the increase in Dst, and at lower energies (<0.5 MeV) due to rapid radial diffusion driven by the strong magnetic activity during the recovery phase of the storm. Heati ng of the electrons by waves may contribute to the energization of the more energetic part (>1.0 MeV) of the outer zone electrons.