Radial diffusion modeling with empirical lifetimes: comparison with CRRES observations

Abstract. A time dependent radial diffusion model is used to quantify the competing effects of inward radial diffusion and losses on the distribution of the outer zone relativistic electrons. The rate of radial diffusion is parameterized by Kp with the loss time as an adjustable parameter. Comparison with HEEF data taken over 500 Combined Release and Radiation Effects Satellite (CRRES) orbits indicates that 1-MeV electron lifetimes near the peak of the outer zone are less than a day during the storm main phase and few days under less disturbed conditions. These values are comparable to independent estimates of the storm time loss rate due to scattering by EMIC waves and chorus emission, and also provide an acceptable representation of electron decay rates following the storm time injection. Although our radial diffusion model, with data derived lifetimes, is able to simulate many features of the variability of outer zone fluxes and predicts fluxes within one order of magnitude accuracy for most of the storms and L values, it fails to reproduce the magnitude of flux changes and the gradual build up of fluxes observed during the recovery phase of many storms. To address these differences future modeling should include an additional local acceleration source and also attempt to simulate the pronounced loss of electrons during the main phase of certain storms.

[1]  R. Thorne,et al.  Parasitic pitch angle diffusion of radiation belt particles by ion cyclotron waves , 1972 .

[2]  Richard M. Thorne,et al.  Electron scattering loss in Earth's inner magnetosphere: 1. Dominant physical processes , 1998 .

[3]  R. Horne,et al.  Model of the energization of outer‐zone electrons by whistler‐mode chorus during the October 9, 1990 geomagnetic storm , 2002 .

[4]  Richard M. Thorne,et al.  Statistical analysis of relativistic electron energies for cyclotron resonance with EMIC waves observed on CRRES , 2003 .

[5]  Louis J. Lanzerotti,et al.  Particle Diffusion in the Radiation Belts , 1974 .

[6]  A. Chan,et al.  Fully adiabatic changes in storm time relativistic electron fluxes , 1997 .

[7]  G. Reeves,et al.  Acceleration and loss of relativistic electrons during geomagnetic storms , 2003 .

[8]  Jay M. Albert,et al.  Radial diffusion analysis of outer radiation belt electrons during the October 9, 1990, magnetic storm , 2000 .

[9]  Richard M. Thorne,et al.  The influence of wave-particle interactions on relativistic electron dynamics during storms , 2013 .

[10]  Richard M. Thorne,et al.  Timescale for radiation belt electron acceleration by whistler mode chorus waves , 2005 .

[11]  Richard M. Thorne,et al.  Relativistic electron pitch-angle scattering by electromagnetic ion cyclotron waves during geomagnetic storms , 2003 .

[12]  R. Horne,et al.  Resonant diffusion of radiation belt electrons by whistler‐mode chorus , 2003 .

[13]  C. Kennel,et al.  Pitch-angle diffusion of radiation belt electrons within the plasmasphere. , 1972 .

[14]  Richard M. Thorne,et al.  Outer zone relativistic electron acceleration associated with substorm‐enhanced whistler mode chorus , 2002 .

[15]  R. Anderson,et al.  An ISEE/Whistler model of equatorial electron density in the magnetosphere , 1992 .

[16]  C. Kennel,et al.  Relativistic electron precipitation during magnetic storm main phase , 1971 .

[17]  R. Thorne,et al.  Equilibrium structure of radiation belt electrons , 1973 .

[18]  J. Albert.  Evaluation of quasi-linear diffusion coefficients for EMIC waves in a multispecies plasma , 2003 .

[19]  R. Horne,et al.  Timescale for MeV electron microburst loss during geomagnetic storms , 2005 .

[20]  Richard M. Thorne,et al.  Potential waves for relativistic electron scattering and stochastic acceleration during magnetic storms , 1998 .

[21]  Scot R. Elkington,et al.  Resonant acceleration and diffusion of outer zone electrons in an asymmetric geomagnetic field , 2003 .

[22]  Richard M. Thorne,et al.  Time dependent radial diffusion modeling of relativistic electrons with realistic loss rates , 2004 .

[23]  T. O'Brien,et al.  Quantification of relativistic electron microburst losses during the GEM storms , 2004 .

[24]  N. Herlofson,et al.  Particle Diffusion in the Radiation Belts , 1962 .

[25]  M. Hudson,et al.  Simulation of the prompt energization and transport of radiation belt particles during the March 24, 1991 SSC , 1993 .

[26]  R. Thorne,et al.  Gyroresonant acceleration of electrons in the magnetosphere by superluminous electromagnetic waves , 2001 .