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| Titel |
A universal mirror wave-mode threshold condition for non-thermal space plasma environments |
| VerfasserIn |
M. P. Leubner, N. Schupfer |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 9, no. 2 ; Nr. 9, no. 2, S.75-78 |
| Datensatznummer |
250006688
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| Publikation (Nr.) |
 copernicus.org/npg-9-75-2002.pdf |
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| Zusammenfassung |
| Magnetic
fluctuations are recognized in a large variety of space plasmas by
increasingly high resolution, in situ observations as mirror wave mode
structures. A typical requirement for the excitation of mirror modes is a
dominant perpendicular pressure in a high-beta plasma environment.
Contrary, we demonstrate from a realistic kinetic analysis how details of
the velocity space distributions are of considerable significance for the
instability threshold. Introducing the most common characteristics of
observed ion and electron distributions by a mixed suprathermal-loss-cone,
we derive a universal mirror instability criterion from an energy
principle for collisionless plasmas. As a result, the transition from two
temperature Maxwellians to realistic non-thermal features provides a
strong source for the generation of mirror wave mode activity, reducing
drastically the instability threshold. In particular, a number of
space-related examples illuminate how the specific structure of the
velocity space distribution dominates as a regulating excitation mechanism
over the effects related to changes in the plasma parameters. |
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