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| Titel |
Numerical study of upper hybrid to Z-mode leakage during electromagnetic pumping of groups of striations in the ionosphere |
| VerfasserIn |
B. Eliasson, T. B. Leyser |
| 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 ; 33, no. 8 ; Nr. 33, no. 8 (2015-08-19), S.1019-1030 |
| Datensatznummer |
250121236
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| Publikation (Nr.) |
 copernicus.org/angeo-33-1019-2015.pdf |
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| Zusammenfassung |
| We investigate numerically the interaction between ionospheric magnetic
field-aligned density striations and a left-hand circularly polarized (L)-mode wave. The L-mode wave is scattered into upper hybrid (UH) waves which
are partially trapped in the striations, but leak energy to
electromagnetic waves in the Z-mode branch. For small-amplitude (1 %)
striations, this loss mechanism leads to a significant reduction in amplitude
of the UH waves. For several striations organized in a lattice, the leaking
of Z-mode waves is compensated by influx of Z-mode radiation from neighboring
striations, leading to an increased amplitude of the weakly trapped UH waves.
For large-amplitude (10 %) striations the trapped UH waves rapidly increase
in amplitude far beyond the threshold for parametric instabilities, and the Z-mode leakage is less important.
The results have relevance for the growth of striations and the onset of UH
and lower hybrid turbulence during electromagnetic high-frequency pumping of
ionospheric plasma, which require large-amplitude UH waves. |
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