Spatial distribution of the demodulated low-frequency field in the ionosphere perturbed by a high-power short-wave radiation

Simplified models of the region of lower ionosphere perturbed by the high-power modulated short-wave radiation of a ground station are used to calculate (in the ray-optics approximation) distributions of the relative amplitude of the demodulated low-frequency field above the maximum of the F2 layer. Calculations are performed for conditions corresponding to the operating conditions of the HAARP station (Alaska, USA). Calculations show that the center of the “effective” ionospheric demodulator is located at altitudes of 50–75 km in the ionosphere and the distribution of the field amplitude has a characteristic narrow (10–20 km) spatial peak, which agrees well with the published results of ground-based and satellite measurements.