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| Titel |
Nonlocal nonlinear coupling of kinetic sound waves |
| VerfasserIn |
O. Lyubchyk, Y. Voitenko |
| 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 ; 32, no. 11 ; Nr. 32, no. 11 (2014-11-13), S.1407-1413 |
| Datensatznummer |
250121131
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| Publikation (Nr.) |
 copernicus.org/angeo-32-1407-2014.pdf |
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| Zusammenfassung |
| We study three-wave resonant interactions among kinetic-scale oblique sound
waves in the low-frequency range below the ion cyclotron frequency. The
nonlinear eigenmode equation is derived in the framework of a two-fluid plasma
model. Because of dispersive modifications at small wavelengths perpendicular
to the background magnetic field, these waves become a decay-type mode. We
found two decay channels, one into co-propagating product waves (forward
decay), and another into counter-propagating product waves (reverse decay).
All wavenumbers in the forward decay are similar and hence this decay is
local in wavenumber space. On the contrary, the reverse decay generates waves
with wavenumbers that are much larger than in the original pump waves and is
therefore intrinsically nonlocal. In general, the reverse decay is
significantly faster than the forward one, suggesting a nonlocal spectral
transport induced by oblique sound waves. Even with low-amplitude sound waves
the nonlinear interaction rate is larger than the collisionless dissipation
rate. Possible applications regarding acoustic waves observed in the solar
corona, solar wind, and topside ionosphere are briefly discussed. |
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