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| Titel |
Features of energetic particle radial profiles inferred from geosynchronous responses to solar wind dynamic pressure enhancements |
| VerfasserIn |
Y. Shi, E. Zesta, L. R. Lyons |
| 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 ; 27, no. 2 ; Nr. 27, no. 2 (2009-02-19), S.851-859 |
| Datensatznummer |
250016419
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| Publikation (Nr.) |
 copernicus.org/angeo-27-851-2009.pdf |
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| Zusammenfassung |
| Determination of the radial profile of phase space density of relativistic
electrons at constant adiabatic invariants is crucial for identifying the
source for them within the outer radiation belt. The commonly used method is
to convert flux observed at fixed energy to phase space density at constant
first, second and third adiabatic invariants, which requires an empirical
global magnetic field model and thus might produce some uncertainties in the
final results. From a different perspective, in this paper we indirectly
infer the shape of the radial profile of phase space density of relativistic
electrons near the geosynchronous region by statistically examining the
geosynchronous energetic flux response to 128 solar wind dynamic pressure
enhancements during the years 2000 to 2003. We thus avoid the disadvantage
of using empirical magnetic field models. Our results show that the flux
response is species and energy dependent. For protons and low-energy
electrons, the primary response to magnetospheric compression is an increase
in flux at geosynchronous orbit. For relativistic electrons, the dominant
response is a decrease in flux, which implies that the phase space density
decreases toward increasing radial distance at geosynchronous orbit and
leads to a local peak inside of geosynchronous orbit. The flux response of
protons and non-relativistic electrons could result from a phase density
that increases toward increasing radial distance, but this cannot be
determined for sure due to the particle energization associated with
pressure enhancements. Our results for relativistic electrons are consistent
with previous results obtained using magnetic field models, thus providing
additional confirmation that these results are correct and indicating that
they are not the result of errors in their selected magnetic field
model. |
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