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| Titel |
Formation of lower-hybrid solitary structures by modulational interaction between lower-hybrid and dispersive Alfvén waves |
| VerfasserIn |
J. O. Hall, G. Stenberg, A. I. Eriksson, M. André |
| 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. 3 ; Nr. 27, no. 3 (2009-03-02), S.1027-1033 |
| Datensatznummer |
250016436
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| Publikation (Nr.) |
 copernicus.org/angeo-27-1027-2009.pdf |
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| Zusammenfassung |
| We investigate the possibility that lower-hybrid solitary structures
(LHSS), which are frequently observed in the Earth's ionosphere and
magnetosphere, are formed as a result of a modulational interaction
between lower-hybrid and dispersive Alfvén waves of initially
small amplitude. A large amplitude lower-hybrid pump wave can
excite density structures with length scales transverse to the
geomagnetic field of the order of the ion gyroradius via a
modulational instability. The structure formation in the nonlinear
stage of the instability is investigated by numerical solutions of
the governing equations, using plasma parameters relevant for
LHSS observations in the upper ionosphere and in the magnetosphere.
The numerical solutions reveal that the
lower-hybrid waves become self-localized inside cylindrically
symmetric (with respect to the ambient magnetic field) density
cavities, in qualitative agreement with observations. Our model
includes thermal electron effects but shows no stabilization at the
ion sound gyroradius, suggesting that any preference of observed
LHSS for that perpendicular scale likely is due to processes
arresting the cavity collapse. |
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