Collisional Rayleigh-Taylor instability and shear-flow in equatorial Spread-F plasma

Abstract. Collisional Rayleigh-Taylor (RT) instability is considered in the bottom side of the equatorial F-region. By a novel nonmodal calculation it is shown that for an applied shear flow in equilibrium, the growth of the instability is considerably reduced. Finite but small amounts of diffusion enhances the stabilization process. The results may be relevant to the observations of long-lived irregularities at the bottom-side of the F-layer.

Key words. Ionosphere (ionospheric irregularities, equatorial ionosphere, plasma waves and instabilities)