Abstract

We report on the POLAR/CEPPAD discovery of a trapped, 60°<θ<120° pitch angle electron population in the outer cusp (7−9+ Re), whose energetic electron component extends from below 30 keV to ∼2 MeV. Because the time variability in the outer cusp precludes mapping with POLAR, we have carried out test particle simulations using the Tsyganenko 1996 model (T96) to demonstrate the trapping of these energy electrons in the outer cusp region and the resonant frequencies of its trapped motion. We discuss the boundaries and regions of the cusp trap and show that it is analogous to the dipole trap. We show that the phase space densities observed there are equal or greater than the phase space densities observed in the radiation belts at constant magnetic moment, thus allowing the possibility of diffusive filling of the radiation belts from the cusp

Department

Physics

Publication Date

6-1998

Journal Title

Geophysical Research Letters

Publisher

American Geophysical Union

Digital Object Identifier (DOI)

10.1029/98GL01399

Document Type

Article

Rights

Copyright 1998 by the American Geophysical Union.

Included in

Physics Commons

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