Evgenii D. Tereshchenko

Statistical tomography of subkilometer irregularities in the high‐latitude ionosphere

[1]xa0First results are reported on statistical tomography of kilometer-scale irregularities in the F layer high-latitude ionosphere from amplitude data of satellite radio probing. Basic formulae for statistical tomography of three-dimensionally (3-D) anisotropic small-scale irregularities are presented. It is shown that 3-D anisotropy disguises spatial distribution of irregularities but is not an insuperable difficulty for tomographic reconstruction. An example is shown of imaging the spatial distribution of the variance of electron density fluctuations over the Kola peninsula in February 1996. Iterative procedure of tomographic inversion was used in the reconstruction. Further steps of applying statistical tomographic approach are outlined.

Radiotomographical Detection of Ionosphere Disturbances Caused by Ground Explosions

Long-lived local disturbances of the ionospheric density over the site of ground industrial explosions were detected by the ionosphere radiotomography method. It is assumed that the density anomalies arise because of the initiation of vortex motion in a neutral component after acoustic impulse passage.

Polarization of ELF waves generated during “beat-wave” heating experiment near cutoff frequency of the Earth-ionosphere waveguide

High-frequency heating of the ionosphere is effective for generating extremely low frequencies (ELF, 3–3000 Hz) through modulation of the auroral electrojet current. While the amplitudes of the resulting ELF waves depend on the auroral electrojet current strength, the polarization of their horizontal magnetic field remains relatively stable. In this work, we determined that at the distance of several wavelengths from an ionospheric ELF source created by two HF heating waves separated by an ELF frequency, polarization parameters are influenced by the Earth-ionosphere waveguide. Previous experiments in the vicinity of the ionospheric ELF source have determined that the right-hand polarization of the magnetic field measured at the ground typically prevails, whereas in this paper we demonstrate that at the distance of 660 km to the east of the European Incoherent Scatter, a circular left-hand polarization dominates. We interpret this effect as a result of “trapping” of the left-hand mode between the upper and lower boundaries of the Earth-ionosphere waveguide, while the right-hand or whistler mode leaks into the ionosphere.