Investigation by backscatter radar of artificial irregularities produced in ionospheric plasma heating experiments

The artificial ionospheric turbulence occurs in the ionosphere illuminated by high power HF radio waves. There are a lot of irregularities stretched along the geomagnetic field in this region. The investigation of the artificially disturbed ionospheric region is based on the reception of back scattered signals (BSS) which permits the basic parameters of this region to be estimated and its inhomogeneous structure to be described.Experiments were carried out using ‘Sura’ heating facility in the frequency range of ? = 4.7–9 MHz (ordinary mode) with the effective radiated power P_eff = 50–70 MW beamed vertically upwards. The most important dynamic and statistical BSS characteristics (the built-up time, the relaxation and autocorrelation times, the BSS amplitude spatial correlation function and power spectra) were measured using probe waves in the frequency range of that made it possible to obtain the basic parameters of the artificial irregularities. The model representation of a disturbed region in a form of a periodic structure gives a possibity to evaluate the scale of the structure, the whole size of the disturbance and its power and to calculate the main BSS characteristics.     

Trapping of sensing radio waves in an artificial large-scale ionospheric cavity

The results of phenomenological analysis of data from oblique chirp sounding of the ionosphere in a 2007 heating experiment with possible recording of the effect of trapping sounding-radiation in an artificial ionospheric cavity and spotlighting it in the near (over the Earth’s surface) zone of the Sura facility are presented. The physical aspects of forming an additional trace on ionograms of oblique radio-sounding of the perturbed region of the ionosphere are discussed.     

Specific behavior of the radioemission wave field near the maximum usable frequency

The character of a change in the wave field in the frequency range near the maximum usable frequency is analyzed for the model of a simple ionospheric layer. The estimates of the characteristic scale of diffraction damping of the wave field in the frequency range, which are in rather good agreement with the experimental data of LFM or chirp sounding of the ionosphere on two mutually perpendicular paths, have been obtained.     

Technology and Operation Mode of Sludge Deposition Polygons as Important Geoenvironmental Factors for Surrounding Areas

Doklady Earth Sciences - A sewage sludge storage facility was built in late 20th and early 21st century to free up land for the construction of a new residential complex Mar’inskii Park. This...     

Acoustic gravity waves and the atmospheric electric field perturbations accompanying them

Data on observations of acoustic gravity waves and variations in the electric field strength in the surface layer of the atmosphere are presented. Analysis of the obtained data shows that synchronous variations in the pressure and electric field strength appear with the passage of a weather front, solar terminator, and in some other cases. It is seen that the amplitude of electric field perturbations is approximately proportional to the amplitude of variation in the pressure. A possible mechanism of generating electric field perturbations during the passage of microbaroms has been considered.     

Autoscala: an aid for different ionosondes

Autoscala is a software to automatically scale ionospheric characteristics from an ionogram. Initially it was only applied to the ionograms recorded by the AIS-INGV ionosondes installed at Rome and Gibilmanna (Italy), and Tucumán (Argentina), that are not able to record the polarization of the received echo. Recently, Autoscala was also applied to the ionograms recorded by the AIS-Parus ionosonde installed at Moscow (Russia), that is not able to tag the received echo in terms of polarization, and by the VISRC2 ionosonde installed at Warsaw (Poland) that is instead able to perform the polarization tagging of the ordinary and extraordinary echoes. This work shows different examples of processing performed on ionograms recorded by all these three different types of ionosondes.     

Possibilities of radio sounding of the ionosphere in the decameter range on board a geostationary satellite

It is shown that besides the known method of topside ionospheric sounding (TS) in the decameter range using low-orbit transit satellites, the same frequency range could be used for ionospheric diagnostics, but using geostationary satellites by the method of multifrequency radio transillumination (MRT). The trajectory and energetic features related to the application of this method in the direct problem of transionospheric sounding of the ionosphere are discussed.     

Analysis of the wave field mode structure on the Moscow–Akademik Vernadskii Antarctic station superlong path

The Doppler spectrum of an exact time harmonic radio signal for the frequency of 5 MHz on the Moscow–Akademik Vernadskii Ukrainian Antarctic station radio path in November 2002, which had two clearly defined spectral groups, has been analyzed. It is shown that an insignificant frequency shift corresponds to a standard radio wave propagation in a short direct direction. The assumption that the formation of a spectral group with a considerable frequency shift is refraction is theoretically justified based on a simplified model of the morning terminator transition region. The field strength, signal-to-noise ratio, and Doppler frequency shift obtained in the scope of the IRI-2001 extended global ionospheric model for the classical radio wave propagation modes on a superlong radio path are estimated.     

Megacity Aerosol Pollution and Atmospheric Electric Field Disturbances

Izvestiya, Atmospheric and Oceanic Physics - The relationship between electric field variations and microparticle concentrations in the atmospheric surface layer has been studied using the example...