The Search for Predictable Features of Relativistic Electron Events: Results from the GEM Storms Campaign

Abstract

We have examined the relativistic electron events associated with four geomagnetic storms driven by CME-produced magnetic clouds in order to discover some of the underlying consistent behavior that is common to these events. The geomagnetic conditions for the four events showed considerable variation as did the fluxes at fixed energies and fixed L-shell. By combining data from nine different satellites and by selecting specific parameters we found several characteristics of the relativistic electron events that were consistent from storm to storm. Our analysis focused on geosynchronous orbit and on L ≃ 4.2 which is near the heart of the outer electron belt. We examined a large number of parameters and combinations of parameters and found that among the most consistent sets were (1) the temporal behavior of the electron fluxes at L≃4.2 and L≃6.6, (2) the temporal evolution of the spectra at L≃4.2 and L≃6.6, and (3) the gradients of the phase space densities between L≃4.2 and L≃6.6, The characteristics of those parameters may be common to all relativistic electron events and if so that they hold important clues to the physical processes operating during these events. The fact that they are common to these four storms already provides an important framework for evaluating the success of various predictive space weather models that are being developed and tested against these four events.