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Titel |
Low frequency eigenmodes of thin anisotropic current sheets and Cluster observations |
VerfasserIn |
L. M. Zelenyi, A. V. Artemyev, A. A. Petrukovich, R. Nakamura, H. V. Malova, V. Y. Popov |
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.861-868 |
Datensatznummer |
250016420
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Publikation (Nr.) |
copernicus.org/angeo-27-861-2009.pdf |
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Zusammenfassung |
The eigenmodes of low frequency perturbations of thin anisotropic current
sheets with a finite value of the normal magnetic field, are investigated in
this paper. It is shown that two possible polarizations of symmetric and
asymmetric modes (sausage and kink) exist where the growth rate of
instabilities is positive. In addition, we demonstrate that a tearing
instability might have a positive growth rate in thin anisotropic current
sheets. The class of relatively fast wavy flapping oscillations observed by
Cluster is described. The main direction of wave motion coincides with the
direction of the current and the typical velocity of this motion is
comparable with the plasma drift velocity in the current sheet. The
comparison of these characteristics with theoretical predictions of the
model of anisotropic thin current sheets, demonstrates that, in principle, the
theory adequately describes the observations. |
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