Bottom-type scattering layers and equatorial spread <i>F</i>
Jicamarca radar observations of bottom-type coherent scattering layers in the post-sunset bottomside F-region ionosphere are presented and analyzed. The morphology of the primary waves seen in radar images of the layers supports the hypothesis of kudeki+bhattacharyya-1999 that wind-driven gradi...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2004-12-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/22/4061/2004/angeo-22-4061-2004.pdf |
| Summary: | Jicamarca radar observations of bottom-type coherent scattering layers
in the post-sunset bottomside F-region ionosphere are presented
and analyzed. The morphology of the primary waves seen in radar
images of the layers supports the hypothesis of
kudeki+bhattacharyya-1999 that wind-driven gradient drift
instabilities are operating. In one layer event when topside
spread <i>F</i> did not occur, irregularities were distributed
uniformly in space throughout the layers. In another event when
topside spread <i>F</i> did eventually occur, the irregularities within
the pre-existing bottom-type layers were horizontally clustered, with
clusters separated by about 30km. The same horizontal periodicity was
evident in the radar plumes and large-scale irregularities that
emerged later in the event. We surmise that horizontal periodicity in
bottom-type layer irregularity distribution is indicative of
large-scale horizontal waves in the bottomside F-region that may
serve as seed waves for large-scale Rayleigh Taylor
instabilities.
<br><br><b>Key words.</b> Ionosphere (equatorial ionosphere; ionospheric
irregularties; plasma waves and instabilities) |
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| ISSN: | 0992-7689 1432-0576 |