Observations and Fokker-Planck Simulations of the L-Shell, Energy, and Pitch Angle Structure of Earth's Electron Radiation Belts During Quiet Times

摘要

abstract_textpThe evolution of the radiation belts in L-shell (L), energy (E), and equatorial pitch angle (alpha(0)) is analyzed during the calm 11-day interval (4-15 March) following the 1 March 2013 storm. Magnetic Electron and Ion Spectrometer (MagEIS) observations from Van Allen Probes are interpreted alongside 1D and 3D Fokker-Planck simulations combined with consistent event-driven scattering modeling from whistler mode hiss waves. Three (L, E, alpha(0)) regions persist through 11 days of hiss wave scattering; the pitch angle-dependent inner belt core (L similar to 2.2 and E 700 keV), pitch angle homogeneous outer belt low-energy core (L similar to 5 and E similar to 100 keV), and a distinct pocket of electrons (L similar to 4.5, 5.5 and E similar to 0.7, 2 MeV). The pitch angle homogeneous outer belt is explained by the diffusion coefficients that are roughly constant for alpha(0) similar to 60 degrees, E 100 keV, 3.5 L L-pp similar to 6. Thus, observed unidirectional flux decays can be used to estimate local pitch angle diffusion rates in that region. Top-hat distributions are computed and observed at L similar to 3-3.5 and E = 100-300 keV./p/abstract_text