Mechanisms for generating oscillations in the infrasound frequency range in the upper atmosphere by periodic high-power radio transmissions

Abstract

Intercomparisons of possible mechanisms for generating infrasound oscillations in the ionosphere in the 100 − 350 km altitude range by high-power periodic radio transmissions from a groundbased HF heater have been made. The most effective mechanism is shown to be modulation of the ionospheric currents near the upper hybrid resonance resulting in the modulation of the ponderomotive force and finally, in the modulation of the atmospheric pressure in the 250 − 350 km altitude range. The heater effective power of 100 MW produces infrasound amplitudes of 1 to 10% at the upper-hybrid resonance altitude level during the day and night, respectively. The theoretical estimates are in good agreement with the observations made by the author with the HF Doppler radar at a distance of ~1000 km from the heater.