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| Titel |
On the origin of falling-tone chorus elements in Earth's inner magnetosphere |
| VerfasserIn |
H. Breuillard, O. Agapitov, A. Artemyev, V. Krasnoselskikh, O. Contel, C. M. Cully, V. Angelopoulos, Y. Zaliznyak, 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 ; 32, no. 12 ; Nr. 32, no. 12 (2014-12-08), S.1477-1485 |
| Datensatznummer |
250121137
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| Publikation (Nr.) |
 copernicus.org/angeo-32-1477-2014.pdf |
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| Zusammenfassung |
| Generation of extremely/very low frequency (ELF/VLF) chorus waves in Earth's
inner magnetosphere has received increased attention recently because of
their significance for radiation belt dynamics. Though past theoretical and
numerical models have demonstrated how rising-tone chorus elements are
produced, falling-tone chorus element generation has yet to be explained. Our
new model proposes that weak-amplitude falling-tone chorus elements can be
generated by magnetospheric reflection of rising-tone elements. Using ray
tracing in a realistic plasma model of the inner magnetosphere, we
demonstrate that rising-tone elements originating at the magnetic equator propagate to
higher latitudes. Upon reflection there, they propagate to lower L-shells
and turn into oblique falling tones of reduced power, frequency, and
bandwidth relative to their progenitor rising tones. Our results are in good
agreement with comprehensive statistical studies of such waves, notably using
magnetic field measurements from THEMIS (Time History of Events and Macroscale Interactions during Substorms) spacecraft. Thus, we conclude that
the proposed mechanism can be responsible for the generation of
weak-amplitude falling-tone chorus emissions. |
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