Phase Variations of Kilometric Radio Waves Associated with Modification of the Ionosphere by High Power Radio Waves

Abstract

Quasi-periodic variations in the phase of kilometric radio waves have been detected to occur at the distance of 1000 km from the “Sura” facility emitting high power, high-frequency radio waves. The main feature of the experiment was the appearance of quasi-periodic variations far away from the facility antenna pattern. The amplitudes of phase variations reached 5÷6°,and the variation period was equal to both the duration of stimulation (5 min) and the duration of the interpulse period (5 min). The amplitude of the phase variations was used to estimate the relative amplitude of the electron density disturbance, which reached 10 %. On reference days, the r. m. s. value of the phase variations never exceeded 0.5°, and the relative fluctuations in electron density were equal to 1÷3%.The observed effect cannot be explained by the acoustic-gravity waves generated by the periodic heating of the ionosphere. It most likely involves coupling in the Earth–atmosphere– ionosphere–magnetosphere system.