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| Titel |
A fluid description for Landau damping of dispersive MHD waves |
| VerfasserIn |
T. Passot, P. L. Sulem |
| 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 ; 11, no. 2 ; Nr. 11, no. 2 (2004-04-14), S.245-258 |
| Datensatznummer |
250009137
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| Publikation (Nr.) |
 copernicus.org/npg-11-245-2004.pdf |
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| Zusammenfassung |
| The dynamics of long oblique MHD waves in a collisionless plasma
permeated by a uniform magnetic field is addressed using a
Landau-fluid model that includes Hall effect and
electron-pressure gradient in a generalized Ohm's law and
retains ion finite Larmor radius (FLR) corrections to the
gyrotropic pressure (Phys. Plasmas 10, 3906, 2003). This
one-fluid model, built to reproduce the weakly
nonlinear dynamics of long dispersive Alfvén waves propagating along an
ambient field, is shown to correctly capture the
Landau damping of oblique magnetosonic waves predicted
by a kinetic theory based on the Vlasov-Maxwell system.
For oblique and kinetic Alfvén waves (for which second order
FLR corrections are to be retained), the linear character of waves
with small but finite amplitudes is established, and
the dispersion relation reproduced in the regime of adiabatic protons and
isothermal electrons, associated with the condition
me/mp << β << Te/Tp,
where β is the squared ratio
of the ion-acoustic to the Alfvén speeds. It is shown that in
more general regimes, the heat fluxes are, to leading order,
not gyrotropic and dependent on the Hall effect to leading order. |
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