Analysis of the response of an HF radio signal to ionospheric plasma disturbances caused by acoustic shock waves

We analyze the form of the response of an HF radio signal scattered by the nonstationary disturbances of the electron density N_e caused by acoustic shock-wave disturbances in the upper atmosphere from rockets in the active section of the trajectory. A typical picture of the manifestation of additional modes in the spectrum of an oblique Doppler HF sounding signal is presented. The evolution of the signal response under different conditions of the experiment is discussed. Siberian Physicotechnical at Tomsk State University, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 42, No. 1, pp. 36–44, January, 1999.     

On the frequency dependence of anomalous attenuation of sounding waves in the case of ionospheric modification by high-power radio emission

The dependence of anomalous attenuation of sounding waves on the frequency f is studied experimentally in the case of ionospheric F-layer modification by high-power radio emission. It is shown that anomalous attenuation increases for |f−f₀| < 20 kHz, f<f₀ (f₀ is the pump-wave frequency) and decreases for f>-f₀ compared with the frequencies that are more distant from f₀. This phenomenon is caused by plasma displacement and formation of a stepped electron-density profile in the region of upper hybrid resonance of the pump wave. Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 41, No. 8, pp. 966–977, August, 1998.     

Microwave and IR radiation of the upper atmosphere during periods of enhanced solar activity

A two-temperature nonequilibrium plasma in the E and D atmospheric layers at heights between 50 and 110 km during periods of enhanced solar activity is formed. The highly excited states (Rydberg states) of the A**N₂ and A**O₂ quasi-molecules are populated due to interaction with the neutral medium in the plasma. This results in propagation delays of the signals of global navigation satellite systems and in enhanced positioning uncertainties. Radiation transitions between the Rydberg states of the quasi-molecules lead to the appearance of super-background noncoherent radiation in the decimeter and infrared ranges. The decimeter radiation degrades the signal-to-noise ratio of navigation systems. The super-background infrared radiation can be used to make the tomography of the excited layer and to detect the Rydberg states.     

Disturbance of the phase of high-power radio waves reflected from the ionospheric F-region

Scientific-Research Radiophysics Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 33, No. 2, pp. 143–149, February, 1990.     

Variations in the ionospheric wave perturbation spectrum during periodic heating of the plasma by high-power high-frequency radio waves

We present the results of spectral analysis of temporal variations in the Doppler frequency shift of the ionosphere-reflected signals from a high-frequency vertical ionospheric sounding radar located near the city of Kharkov in the days of exposure of the ionospheric plasma to the high-power radio emission of the Sura facility (Nizhny Novgorod) and in the reference day in the absence of such an exposure. It was established that the spectral characteristics of quasiperiodic variations in the Doppler frequency shift in the range of periods 10–60 min in the days of work of the facility and in the reference day differed significantly. This is considered as evidence in favor of the generation (amplification) of acoustic–gravity waves propagating at the ionospheric altitudes by high-power periodic high-frequency radiation of the Sura facility.