Properties of radio wave reflection from an optically thick, plane monotonic layer of ionospheric plasma with random density irregularities are considered by investigating numerically the influence of multiple scattering on the angular distribution and the integral intensity of the reflected signal. We use an improved solution of the radiative transfer equation in the approximation of small‐angle scattering in invariant ray coordinates (“SASIRC”). The case of midlatitude ionosphere conditions is treated in most detail, but some conclusions about latitudinal dependence are also obtained, for both vertical and slightly oblique sounding cases. Conclusions from earlier versions of the theory showing a strong anomalous‐attenuation effect are confirmed, with adjustments of the quantitative results. We describe a special amplitude calibration procedure for estimation of anomalous attenuation in practical experiments using dynasonde techniques, and discuss the application of our results to an explanation of ionogram spread F.

The influence of multiple scattering in a plasma layer with random irregularities on the propagation time of a totally reflected pulse signal has been considered. Two approaches have been implemented. The first one is based on an analytical solution of the radiative transfer equation. The second one is based on a numerical simulation in the spirit of the Monte Carlo technique. The general conclusion is that, subject to relative position of a transmitter and a receiver and the irregularity shape, one can observe both a decrease and an increase of the propagation time in comparison with the reflection from the same layer deprived of random irregularities. The numerical estimates made in this paper regard the case of radio sounding of the ionospheric plasma. It has been shown that the magnitude of the considered effect is of the order of the characteristic pulse length applied in the ionosphere vertical sounding.

The radiation energy balance equation describing propagation of nonmonochromatic radiation (pulses of waves and modulated radiation) in a plane slab of magnetized plasma with random irregularities in the invariant ray coordinates has been obtained. Its solution in the small angle (in the invariant ray variables) scattering approximation has been considered.

This paper presents a theoretical study of the influence of electron density small-scale irregularities on radio propagation under vertical sounding of the equatorial ionosphere. The sounder is assumed to radiate in the plane perpendicular to geomagnetic field lines. An approximate analytical solution of the equation of radiation energy balance in a plane layer of randomly inhomogeneous plasma has been obtained for this case. Analysis of the results shows that multiple scattering leads to attenuation of signal power and change of the signal arrival angles in the sounder vicinity.

Numerical simulation of radio energy transfer in the ionospheric layer with random small-scale irregularities for the case of a point ground-based source and total reflection has been carried out using a specially designed algorithm based on Monte Carlo method ideas. The model demonstrates a redistribution of the reflected radiation power at the Earth's surface caused by multiple scattering. The data obtained can serve as confirmation of the effect of the anomalous attenuation of the signal power in the vicinity of the sounder. This result is in agreement with a more rigorous theory of the anomalous attenuation effect based on the solution of the radiative transfer equation.

The idea of new diagnostics method for the small-scale irregular structures of magnetically confined plasma is suggested in the present paper. The method can be based on measurements of intensity attenuation of the normal sounding waves. Anomalous attenuation arises due to multiple scattering effects investigated earlier for ionospheric radio propagation. It has been shown that multiple scattering regime can realize in a tokamak plasma. Calculations of normal sounding wave anomalous attenuation in a tokamak plasma have been carried out. This quantity is large enough to be registered experimentally.