Nonlinear Theory and Experimental Observations of the Local Collisional Rayleigh-Taylor Instability in a Descending Equatorial Spread-F Ionosphere.
NAVAL RESEARCH LAB WASHINGTON DC
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The nonlinear evolution of the local collisional Rayleigh-Taylor instability in downward-moving equatorial F layers has been studied in a coordinated theoretical and experimental program dealing with actual conditions of bottomside spread F. For ambient bottomside electron density gradient scale lengths L8 and 25 km, we find large percentage depletions and inverse power law spatial power spectra over the intermediate wavelength range wavelength25 m-1 km. In addition we outline a nonlinear theory of the collisional Rayleigh-Taylor instability applicable to an upward or downward moving equatorial F region ionosphere. These results represent the first definitive comparison between experiment and theory with their agreement lending further support to the belief that the collisional Rayleigh-Taylor instability is responsible for large scale size irregularities that occure under conditions of equatorial spread F.
- Atmospheric Physics
- Plasma Physics and Magnetohydrodynamics