G. I. Grigor’ev

Acoustic-gravity waves in the earth’s atmosphere (review)

We present the modern theory of small-amplitude acoustic-gravity waves (AGWs) in the Earth’s atmosphere. Main attention is paid to the propagation and radiation of AGWs by different sources. We also consider problems of their dissipation, stability, and interaction with the ionospheric plasma. Basic methods of detecting the wave processes in the upper atmosphere in the AGW frequency range are briefly discussed. Experimental data on atmospheric inhomogeneities are compared with theoretical findings.

Response of mesospheric ozone to the heating of the lower ionosphere by high-power HF radio emission

We detected a decrease in the intensity of microwave radiation at the atmospheric ozone line at a frequency of 110836.04 MHz during ionospheric modification by high-power HF radiowaves radiated by the Sura Ionospheric Heating Facility. The obtained experimental data allowed us to hypothesize that this effect was caused by the fact that mesospheric ozone was affected by internal gravity waves generated in the E region of the ionosphere during its high-power HF radiowave heating.

Spectral characteristics of magnetogravity waves generated by high energy mass source in the equatorial region of the atmosphere, Part II

In the first part of study the possibility of high frequency (HF) and low frequency (LF) modes of magnetogravity waves (MGW) propagation in the equatorial atmosphere in conditions of ionospheric F2 layer is demonstrated taking into account the finite conductivity. Here the spectral features of the excited HF MGW mode is studied. At the second part of study the dispersion relations for LF MGW in the ionospheric equatorial region is received. The spectral features of the disturbed components of medium displacement for LF MGW generated by a mass source are investigated. The results are applied to calculate the values of the spectral components of magnetogravity density, pressure and magnetic field disturbances caused by horizontal meteor sweep. The estimates may be useful in the analysis of ionospheric disturbances excited by high-energy geophysical sources.

Vertical Velocities and Temperature of the Neutral Component in the Upper Atmosphere

Results of measurements of the velocity of the vertical plasma motion and the temperature of the neutral component in the upper atmosphere and comparison of variations in these parameters have been described. The measurements have been carried out by the resonance scattering of radio waves by artificial periodic irregularities in the ionospheric plasma. The irregularities arise when the ionosphere is modificated by a powerful high-frequency radio emission from a Sura midlatitude heating facility. Comparison has been conducted using experimental data on altitude- and time-dependent variations in the above parameters obtained in experiments of 2010 and 2014. It has been shown that, above 100 km, wavelike variations in temperature and velocity are commonly observed simultaneously. In the absence of wavelike variations, there is a tendency to an increase in temperature with an increase in the velocity of the vertical plasma motion regardless of direction. This tendency can be attributed to thermal flows directed upward from the turbulent region of the ionosphere.