Heliophysics Science Division
Sciences and Exploration Directorate - NASA's Goddard Space Flight Center

April 22, 2011, 12:00 pm - 1:00 pm

April 22, 2011, 12:00 pm - 1:00 pm

Identifying Loss Mechanisms of Radiation Belt Electrons During Flux Dropout Events



Dr. Chia-Lin Huang, University of New Hampshire

Since the discovery of Earth's radiation belts, a major interest of scientists has been to identify the physical processes that control the violently fluctuating and seemingly unpredictable flux levels of the outer belt. This belt (~3-10 Re) is populated by hundred keV to MeV electrons--sometimes referred to as "killer electrons" because they can penetrate shielding, damage satellite electronics, and cause spacecraft failures. The electron flux level is maintained through a competition between multiple source and loss processes occurring within the magnetosphere and driven by the solar wind. While most of the attention has focused on understanding electron flux enhancement, data from the geosynchronous regions uncovered many unexplained rapid flux decreases. The two possible loss mechanisms include precipitation into the atmosphere due to wave-particle interactions and drift loss of electrons past the magnetopause boundary. There has been limited progress, however, in identifying and quantifying these loss mechanisms during electron dropout events. Thus, we both determine the relative importance of loss mechanisms that control the relativistic electron flux dropouts at geosynchronous orbit and characterize the preferential solar wind conditions for each loss mechanism.