Artificial control of equatorial spread-F

Abstract

We have studied the influence of a large amplitude electric field oscillating near the upper hybrid frequency on the dispersion characteristics of low frequency Rayleigh-Taylor modes and collisional drift modes. Since these modes have been proposed as principal constituents of spread-F, we investigate the conditions for the parametric excitation or control of these F-region irregularities, by an external field. We obtain the modified growth rates as well as the threshold power necessary to carry out such a ground based 'modification' experiment. The propagation characteristics of the pump wave are also briefly discussed.