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Radial diffusion modeling with empirical lifetimes: comparison with CRRES observations

Shprits Y. Y., R. M. Thorne, G. D. Reeves, R. Friedel, (2005), Radial diffusion modeling with empirical lifetimes: comparison with CRRES observations, Annales Geophysicae, 23, 1467–1471, doi:10.5194/angeo-23-1467-2005

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.

Authors (sorted by name)

Friedel Reeves Shprits Thorne

Journal / Conference

Annales Geophysicae

Acknowledgments

Support for this study came from the Collaborative Research Minigrant Program of (IGPP/LANL). The research was also funded in part by NSF grant ATM-0402615 and NASA grant NNG04GN44G

Grants

ATM-0402615 NNG04GN44G

Bibtex

@Article{angeo-23-1467-2005,
AUTHOR = {Shprits, Y. Y. and Thorne, R. M. and Reeves, G. D. and Friedel, R.},
TITLE = {Radial diffusion modeling with empirical lifetimes: comparison with CRRES observations},
JOURNAL = {Annales Geophysicae},
VOLUME = {23},
YEAR = {2005},
NUMBER = {4},
PAGES = {1467--1471},
URL = {https://www.ann-geophys.net/23/1467/2005/},
DOI = {10.5194/angeo-23-1467-2005},
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.}
}