Bibliography
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Radial diffusion simulations of the 20 September 2007 radiation belt dropout
Author | Albert, J.; |
Keywords | radial diffusion |
Abstract | This is a study of a dropout of radiation belt electrons, associated with an isolated solar wind density pulse on 20 September 2007, as seen by the solid-state telescopes (SST) detectors on THEMIS (Time History of Events and Macroscale Interactions during Substorms). Omnidirectional fluxes were converted to phase space density at constant invariants M = 700 MeV G-1 and K = 0.014 RE G1/2, with the assumption of local pitch angle α ≈ 80\textdegree and using the T04 magnetic field model. The last closed drift shell, which was calculated throughout the time interval, never came within the simulation outer boundary of L* = 6. It is found, using several different models for diffusion rates, that radial diffusion alone only allows the data-driven, time-dependent boundary values at Lmax = 6 and Lmin = 3.7 to propagate a few tenths of an RE during the simulation; far too slow to account for the dropout observed over the broad range of L* = 4\textendash5.5. Pitch angle diffusion via resonant interactions with several types of waves (chorus, electromagnetic ion cyclotron waves, and plasmaspheric and plume hiss) also seems problematic, for several reasons which are discussed. |
Year of Publication | 2014 |
Journal | Annales Geophysicae |
Volume | 32 |
Number of Pages | 925-934 |
Section | |
Date Published | 11/2014 |
ISBN | |
URL | http://www.ann-geophys.net/32/925/2014/ |
DOI | 10.5194/angeo-32-925-2014 |