Bottom-type scattering layers and equatorial spread F

Other literature type English OPEN
Hysell, D. L. ; Chun, J. ; Chau, J. L. (2004)
  • Journal: (issn: 1432-0576, eissn: 1432-0576)
  • Related identifiers: doi: 10.5194/angeo-22-4061-2004
  • Subject:
    arxiv: Physics::Atmospheric and Oceanic Physics | Physics::Space Physics

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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