Ground-based acoustic parametric generator impact on the atmosphere and ionosphere in an active experiment

Abstract

Abstract. We develop theoretical basics of active experiments with two beams of acoustic waves, radiated by a ground-based sound generator. These beams are transformed into atmospheric acoustic gravity waves (AGWs), which have parameters that enable them to penetrate to the altitudes of the ionospheric E and F regions where they influence the electron concentration of the ionosphere. Acoustic waves are generated by the ground-based parametric sound generator (PSG) at the two close frequencies. The main idea of the experiment is to design the output parameters of the PSG to build a cascade scheme of nonlinear wave frequency downshift transformations to provide the necessary conditions for their vertical propagation and to enable penetration to ionospheric altitudes. The PSG generates sound waves (SWs) with frequencies f 1 = 600 and f 2 = 625 Hz and large amplitudes (100-420 m s −1 ). Each of these waves is modulated with the frequency of 0.016 Hz. The novelty of the proposed analytical-numerical model is due to simultaneous accounting for nonlinearity, diffraction, losses, and dispersion and inclusion of the two-stage transformation (1) of the initial acoustic waves to the acoustic wave with the difference frequency f = f 2 − f 1 in the altitude ranges 0-0.1 km, in the strongly nonlinear regime, and (2) of the acoustic wave with the difference frequency to atmospheric acoustic gravity waves with the modulational frequency in the altitude ranges 0.1-20 km, which then reach the altitudes of the ionospheric E and F regions, in a practically linear regime. AGWs, nonlinearly transformed from the sound waves, launched by the two-frequency ground-based sound generator can increase the transparency of the ionosphere for the electromagnetic waves in HF (MHz) and VLF (kHz) ranges. The developed theoretical model can be used for interpreting an active experiment that includes the PSG impact on the atmosphere-ionosphere system, measurements of electromagnetic and acoustic fields, study of the variations in ionospheric transparency for the radio emissions from galactic radio sources, optical measurements, and the impact on atmospheric aerosols. The proposed approach can be useful for better understanding the mechanism of the acoustic channel of seismo-ionospheric coupling.

Analysis of shock wave propagation in the atmosphere through generated sound waves

“…The results of the analysis of sound waves generated by a shock wave released by anti-hail acoustic guns are given in [5]. The time dependence of the frequency and intensity of acoustic waves in the frequency range from 100 to 5000 Hz was obtained in [4][5][6][7][8]. In reference [5], it was established that the shock wave released by anti-hail acoustic guns reaches the ionosphere at an altitude of about 100 km.…”

“…In reference [5], it was established that the shock wave released by anti-hail acoustic guns reaches the ionosphere at an altitude of about 100 km. This result was obtained through the analysis of the physical processes described in references [4][5][6]. Theoretical aspects of shock wave propagation are described in [7][8][9].…”

Spectral Analysis and Information Entropy Approaches to Data of VLF Disturbances in the Waveguide Earth-Ionosphere

“…In the approximation of geometrical optics, relations were obtained that allow us to estimate fluctuations in neutral density and vertical displacement of the neutral gas volume at reflection heights from fluctuations in the amplitudes of radio waves. An influence on the atmosphere and ionosphere by nonlinear AGWs caused by tsunami has been modeled theoretically in [ 25 ]; corresponding influence caused by ground-based acoustic generator has been established experimentally in [ 26 ] and theoretically in [ 27 , 28 , 29 , 30 , 31 ]. As shown in the review by [ 32 ], a study of VLF waves in the WGEI allows us to cover the wide range of the physical processes in the system of Atmosphere–Ionosphere, in particular “lightning-induced short term perturbations; extra-terrestrial radiation bursts; energetic particle precipitation events; solar eclipses; lower atmospheric waves penetrating into the D-region; sudden stratospheric warming events; the annual oscillation; the solar cycle; and, finally, the potential use of VLF narrow-band measurements as an anthropogenic climate change monitoring technique”.…”

Влияние Звуковой Волны Нарадиальный Температурный Градиент Газа Положительного Столба

“…К ним относятся, например, влияние на такие параметры плазмы, как напряженность электрического поля внутри плазмы, распределение концентрации заряженных частиц, которое тесно связано с температурой газа [1,2]. Акустические волны также могут воздействовать на совокупность заряженных частиц и вызывать излучение электромагнитных волн в различных диапазонах -от УНЧ до светового [3][4][5]. Второе направление -влияние плазмы на параметры акустических волн, например, усиление звука и нестабильности в плазме [6].…”