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Titel |
Coherent whistler emissions in the magnetosphere – Cluster observations |
VerfasserIn |
E. M. Dubinin, M. Maksimovic, N. Cornilleau-Wehrlin, D. Fontaine, P. Travnicek, A. Mangeney, O. Alexandrova, K. Sauer, M. Fraenz, I. Dandouras, E. Lucek, A. Fazakerley, A. Balogh, M. André |
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 ; 25, no. 1 ; Nr. 25, no. 1 (2007-02-01), S.303-315 |
Datensatznummer |
250015779
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Publikation (Nr.) |
copernicus.org/angeo-25-303-2007.pdf |
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Zusammenfassung |
The STAFF-SC observations complemented by the data from other
instruments on Cluster spacecraft were used to study the main
properties of magnetospheric lion roars: sporadic bursts of whistler
emissions at f~0.1–0.2fe where fe is the electron
gyrofrequency. Magnetospheric lion roars are shown to be similar to
the emissions in the magnetosheath while the conditions for their
generation are much less favorable: the growth rate of the cyclotron
temperature anisotropy instability is much smaller due to a smaller
number of the resonant electrons. This implies a nonlinear mechanism
of generation of the observed wave emissions. It is shown that the
observed whistler turbulence, in reality, consists of many nearly
monochromatic wave packets. It is suggested that these structures
are nonlinear Gendrin's whistler solitary waves. Properties of
these waves are widely discussed. Since the group velocity of
Gendrin's waves is aligned with the magnetic field, these well
guided wave packets can propagate through many magnetic "bottles"
associated with mirror structures, without being
trapped. |
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