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| Titel |
Chorus wave-normal statistics in the Earth's radiation belts from ray tracing technique |
| VerfasserIn |
H. Breuillard, Y. Zaliznyak, V. Krasnoselskikh, O. Agapitov, A. Artemyev, G. Rolland |
| 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 ; 30, no. 8 ; Nr. 30, no. 8 (2012-08-21), S.1223-1233 |
| Datensatznummer |
250017256
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| Publikation (Nr.) |
 copernicus.org/angeo-30-1223-2012.pdf |
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| Zusammenfassung |
| Discrete ELF/VLF (Extremely Low Frequency/Very Low Frequency)
chorus emissions are one of the most intense electromagnetic plasma waves
observed in radiation belts and in the outer terrestrial magnetosphere. These
waves play a crucial role in the dynamics of radiation belts, and are
responsible for the loss and the acceleration of energetic electrons. The
objective of our study is to reconstruct the realistic distribution of chorus
wave-normals in radiation belts for all magnetic latitudes. To achieve this
aim, the data from the electric and magnetic field measurements onboard
Cluster satellite are used to determine the wave-vector distribution of the
chorus signal around the equator region. Then the propagation of such a wave
packet is modeled using three-dimensional ray tracing technique, which
employs K. Rönnmark's WHAMP to solve hot plasma dispersion relation along
the wave packet trajectory. The observed chorus wave distributions close to
waves source are first fitted to form the initial conditions which then
propagate numerically through the inner magnetosphere in the frame of the WKB
approximation. Ray tracing technique allows one to reconstruct wave packet
properties (electric and magnetic fields, width of the wave packet in
k-space, etc.) along the propagation path. The calculations show the
spatial spreading of the signal energy due to propagation in the
inhomogeneous and anisotropic magnetized plasma. Comparison of wave-normal
distribution obtained from ray tracing technique with Cluster observations up
to 40° latitude demonstrates the reliability of our approach and
applied numerical schemes. |
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