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| Titel |
Effect of plasma density on diffusion rates due to wave particle interactions with chorus and plasmaspheric hiss: extreme event analysis |
| VerfasserIn |
A. Sicard-Piet, D. Boscher, R. B. Horne, N. P. Meredith, V. Maget |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 32, no. 8 ; Nr. 32, no. 8 (2014-08-29), S.1059-1071 |
| Datensatznummer |
250121102
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| Publikation (Nr.) |
 copernicus.org/angeo-32-1059-2014.pdf |
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| Zusammenfassung |
| Wave particle interactions play an important role in controlling the
dynamics of the radiation belts. The purpose of this study is to estimate
how variations in the plasma density can affect diffusion rates resulting
from interactions between chorus waves and plasmaspheric hiss with energetic
particles and the resulting evolution of the energetic electron population.
We perform a statistical analysis of the electron density derived from the
plasma wave experiment on the CRRES satellite for two magnetic local time
sectors corresponding to near midnight and near noon. We present the
cumulative probability distribution of the electron plasma density for three
levels of magnetic activity as measured by Kp. The largest densities are
seen near L* = 2.5 while the smallest occur near L* = 6. The broadest
distribution, corresponding to the greatest variability, occurs near L* = 4. We calculate diffusion coefficients for plasmaspheric hiss and whistler
mode chorus for extreme values of the electron density and estimate the
effects on the radiation belts using the Salammbô model. At L* = 4 and
L* = 6, in the low density case, using the density from the 5th percentile
of the cumulative distribution function, electron energy diffusion by chorus
waves is strongest at 2 MeV and increases the flux by up to 3 orders of
magnitude over a period of 24 h. In contrast, in the high density case,
using the density from the 95th percentile, there is little
acceleration at energies above 800 keV at L* = 6, and virtually no
acceleration at L* = 4. In this case the strongest energy diffusion occurs
at lower energies around 400 keV where the flux at L* = 6 increases 3
orders of magnitude. |
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