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| Titel |
Ion temperature anisotropy effects on threshold conditions of a shear-modified current driven electrostatic ion-acoustic instability in the topside auroral ionosphere |
| VerfasserIn |
P. J. G. Perron, J.-M. A. Noël, K. Kabin, J.-P. St.-Maurice |
| 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 ; 31, no. 3 ; Nr. 31, no. 3 (2013-03-07), S.451-457 |
| Datensatznummer |
250019005
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| Publikation (Nr.) |
 copernicus.org/angeo-31-451-2013.pdf |
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| Zusammenfassung |
| Temperature anisotropies may be encountered in space plasmas when there is a
preferred direction, for instance, a strong magnetic or electric field. In
this paper, we study how ion temperature anisotropy can affect the threshold
conditions of a shear-modified current driven electrostatic ion-acoustic
(CDEIA) instability. In particular, this communication focuses on
instabilities in the context of topside auroral F-region situations and in
the limit where finite Larmor radius corrections are small. We derived a new
fluid-like expression for the critical drift which depends explicitly on ion
anisotropy. More importantly, for ion to electron temperature ratios typical
of F-region, solutions of the kinetic dispersion relation show that ion
temperature anisotropy may significantly lower the drift threshold required
for instability. In some cases, a perpendicular to parallel ion temperature
ratio of 2 and may reduce the relative drift required for the onset of
instability by a factor of approximately 30, assuming the ion-acoustic speed
of the medium remains constant. Therefore, the ion temperature anisotropy
should be considered in future studies of ion-acoustic waves and
instabilities in the high-latitude ionospheric F-region. |
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