Search

We discuss the results of studies of natural and artificial small-scale turbulence in the upper ionosphere. The first data on the spectrum of sizes of irregularities at altitudes 240–340 km were obtained in the 1970s by the method of aspect scattering of radio waves and the method of radio-raying of the ionosphere by radio signals from Earth-orbiting satellites. New data on the irregularities with a size of about 20 m were obtained by the method of backscattering of radio waves in the period 2009–2011 using the “Sura” facility radar. The radar measurements allow one to complement the empirical model of irregularities in the F layer of the ionosphere.

The signals of radio-wave backscattering from small-scale irregularities located at the altitudes from 200 to 400 km were first recorded by the “Sura” facility radar in 2006. The experiments with the “Sura” facility were repeated in the summer of 2009. Radar signals scattered in the altitude range 300–500 km were observed in 10% of the cases. Pronounced variation in the radar-signal intensity was observed during modification of the ionosphere by high-power radio waves. We discuss the possibility of an experimental study of the spectrum of small-scale turbulence in the upper ionosphere by the modified method of backscattering of HF waves.

We present the results of numerical simulation and physical experiments to verify the possibility of generating a virtual superluminal VLF source by HF ionospheric heating with a scanning beam.

The results of an investigation of VLF radiation generated by a mobile ionospheric source are presented. Radiation at frequency F appears due to the operation of two powerful HF transmitters at frequencies f and f±F fed to two space-separated antennas. The intensity of the signals received at the ground depends on the location of the source with respect to the receiving point and is determined by the sign and value of the frequency shift F. The proposed model of the phenomena satisfactorily explains the experimental results.

The essence of the correlation-sounding method is to take the correlation function of direct and ionosphere-reflected signals.

Partial realization of such a control algorithm allowed us in a number of experiments to increase the registration time and intensity of scattered ultrashort waves