Parameters of artificial irregularities according to results of the observation of backscattering during oblique sounding

The diagnostics of the small-scale structure of an artificially heated region in the ionosphere was performed on the basis of backscattering signals; the heating of the ionosphere was carried out on a midlatitude path during August-September 1980 at two frequencies (4.6 and 5.75 MHz) using a transmitter with a power of 150 kW. The results clearly display the effect of the foreshortening dependence of short-wave scattering by anisotropic irregularities. In addition, it is shown that as the f0F2 approaches the heating frequency, the scattering cross section initially increases, reaches a maximum value when the difference between the critical frequency and the heating frequency is about 1 MHz, and then appreciably decreases. It is noted that the experimental approach proposed here can be used to choose optimal conditions with regard to the effect of artificial disturbances on ionospheric propagation.