Plasma-perturbation evolution in the F-region and estimation of ionospheric parameters from sounding data

The problem of plasma perturbation caused by the point emission of energy on the order of 1014 ergs in the F-region is examined. Perturbation is observed by radio-frequency sounding in the first 15 sec after an explosion. A homogeneous medium and spherical symmetry of the charge are assumed. The conditions for the appearance of strong shock waves in the F-region are analyzed. The structure of the plasma-perturbation front for a shock wave with a Mach number of less than 10 is found everywhere except for a narrow open-quotes layerclose quotes near a plane perpendicular to the constant magnetic field. A theoretical model is compared with experimental results