Energy-dependent dynamics of keV to MeV electrons in the inner zone, outer zone, and slot regions.
We present observations of the radiation belts from the Helium Oxygen Proton Electron and Magnetic Electron Ion Spectrometer particle detectors on the Van Allen Probes satellites that illustrate the energy dependence and L shell dependence of radiation belt enhancements and decays. We survey events in 2013 and analyze an event on 1 March in more detail. The observations show the following: (a) at all L shells, lower energy electrons are enhanced more often than higher energies; (b) events that fill the slot region are more common at lower energies; (c) enhancements of electrons in the inner zone are more common at lower energies; and (d) even when events do not fully fill the slot region, enhancements at lower energies tend to extend to lower L shells than higher energies. During enhancement events the outer zone extends to lower L shells at lower energies while being confined to higher L shells at higher energies. The inner zone shows the opposite with an outer boundary at higher L shells for lower energies. Both boundaries are nearly straight in log(energy) versus L shell space. At energies below a few 100 keV, radiation belt electron penetration through the slot region into the inner zone is commonplace, but the number and frequency of "slot filling" events decreases with increasing energy. The inner zone is enhanced only at energies that penetrate through the slot. Energy- and L shell-dependent losses (that are consistent with whistler hiss interactions) return the belts to more quiescent conditions.
Space Science and Applications Group Los Alamos National Laboratory Los Alamos New Mexico USA; The New Mexico Consortium Los Alamos New Mexico USA.
Geoffrey D
GD
Reeves
Space Science and Applications Group Los Alamos National Laboratory Los Alamos New Mexico USA; The New Mexico Consortium Los Alamos New Mexico USA.
Reiner H W
RH
Friedel
Space Science and Applications Group Los Alamos National Laboratory Los Alamos New Mexico USA; The New Mexico Consortium Los Alamos New Mexico USA.
Brian A
BA
Larsen
Space Science and Applications Group Los Alamos National Laboratory Los Alamos New Mexico USA.
Ruth M
RM
Skoug
Space Science and Applications Group Los Alamos National Laboratory Los Alamos New Mexico USA.
Herbert O
HO
Funsten
The Aerospace Corporation Los Angeles California USA.
Seth G
SG
Claudepierre
The Aerospace Corporation Los Angeles California USA.
Joseph F
JF
Fennell
The Aerospace Corporation Los Angeles California USA.
Drew L
DL
Turner
The New Mexico Consortium Los Alamos New Mexico USA.
Mick H
MH
Denton
Institute for the Study of Earth, Oceans, and Space and Department of Physics University of New Hampshire Durham New Hampshire USA.
Harlan E
HE
Spence
The Aerospace Corporation Los Angeles California USA.
J Bernard
JB
Blake
Laboratory for Atmospheric and Space Physics University of Colorado Boulder Boulder Colorado USA.
Daniel N
DN
Baker
acceleration; energetic particles; inner zone; outer zone; radiation belts; slot region