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| Titel |
Limitations of Hall MHD as a model for turbulence in weakly collisional plasmas |
| VerfasserIn |
G. G. Howes |
| 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 ; 16, no. 2 ; Nr. 16, no. 2 (2009-03-27), S.219-232 |
| Datensatznummer |
250013133
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| Publikation (Nr.) |
 copernicus.org/npg-16-219-2009.pdf |
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| Zusammenfassung |
| The limitations of Hall MHD as a model for turbulence in weakly
collisional plasmas are explored using quantitative comparisons to
Vlasov-Maxwell kinetic theory over a wide range of parameter
space. The validity of Hall MHD in the cold ion limit is shown, but
spurious undamped wave modes exist in Hall MHD when the ion
temperature is finite. It is argued that turbulence in the dissipation
range of the solar wind must be one, or a mixture, of three
electromagnetic wave modes: the parallel whistler, oblique whistler,
or kinetic Alfvén waves. These modes are generally well described by
Hall MHD. Determining the applicability of linear kinetic damping
rates in turbulent plasmas requires a suite of fluid and kinetic
nonlinear numerical simulations. Contrasting fluid and kinetic
simulations will also shed light on whether the presence of spurious
wave modes alters the nonlinear couplings inherent in turbulence and
will illuminate the turbulent dynamics and energy transfer in the
regime of the characteristic ion kinetic scales. |
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