E. A. Benediktov

Diagnostics of the lower ionosphere by the method of resonance scattering of radio waves

Abstract Results are presented on measurements of lower ionosphere parameters (electron concentration, coefficient of ambipolar diffusion, etc.) by the method of resonance scattering of radio waves by periodic artificial irregularities. The method of resonance scattering is based on the generation of periodic irregularities in the ionospheric plasma by powerful radio emission and investigation of the characteristics of the back scattering of diagnostic radio waves by these irregularities.

Diagnostics of the ionosphere and neutral atmosphere at E-region heights using artificial periodic inhomogeneities

Abstract An overview of studies of the ionospheric E -region using artificial periodic inhomogeneities (API) is presented. Generation of the electron density API is considered theoretically. Methods of measurements of the electron density profile and neutral atmosphere temperature, density and vertical velocity are outlined and illustrated by experimental results. Some suggestions concerning investigations of the atmospheric turbulence using API are presented.

Studies of the ionosphere and neutral atmosphere using artificial periodic inhomogeneities in the ionospheric plasma

This paper is devoted to a ground-based method for diagnostics of the ionosphere and neutral atmosphere. This method uses one of the numerous physical phenomena observed in the ionosphere illuminated by a high-power radio wave, namely, the generation of artificial periodic inhomogeneities. New results on the ionospheric and atmospheric parameter measurements at E region heights are given.

Artificial periodic inhomogeneities of the ionosperic plasma as a promising line in the ionospheric research

This paper is dedicated to a new method of ionospheric studies, developed at the Radiophysical Research Institute (NIRFI) and based on the creation of artificial periodic inhomogeneities (APIs) of the ionospheric plasma. We review the techniques and present the results of determination of the basic parameters of the ionosphere and atmosphere.

Studies of the Irregular Structure of the Ionosphere using Scattering of Radio Waves on Artificial Periodic Inhomogeneities

We present new results of our studies of the irregular structure of the ionosphere using artificial periodic inhomogeneities (APIs) of the ionospheric plasma. The observations were carried out from 9:00 to 17:00 in August 10–12, 1999 with a height step of 0.7xa0km and digital registration and real-time processing of the signal quadratures. It is shown that in many cases, the amplitude of the scattered signal is determined by the interference of radio waves scattered on APIs and on natural ionospheric formations including sporadic layers and large-scale natural irregularities. This allows one to study the irregular structure of the lower ionosphere by analyzing height-time dependences of the amplitude and phase of the scattered signal.

Study of the Twilight D Region of the Ionosphere using Artificial Periodic Inhomogeneities

We analyze the behavior of the ionospheric D region during sunset and sunrise using the results of measurements performed in August 2000 at the “Sura” facility by the method of artificial periodic inhomogeneities. The measured altitude profiles of the relaxation time and the scattered-signal amplitude are interpreted within the framework of a model with single negative-ion species O2-. Variations in the number densities of atomic and excited molecular oxygen and the altitude profiles of the electron density are found.

A study of the winter-time D-region using the partial reflection technique

Abstract The results of observations performed by a partial reflection radar at Gorky (56,1°N, 44,3°E) during the winters of 1982–1983 and 1983–1984 are presented. The following D-region parameters were measured: electron densities for fixed solar zenith angles (1982–1983 χ ~ 78°, 1983–1984 χ ~ 78°, 84°), wind velocities and frequency spectra of scattered signals. On the basis of simultaneous wind and frequency spectrum measurements the horizontal scale of scattering irregularities is estimated.

Artificial periodic inhomogeneities and a model for the lower part of theD region

The measured height profiles of the relaxation time and amplitudes of artificial periodic inhomogeneities (API) in the ionospheric D region are compared with the model. It is shown that the height dependences of the relaxation time of APIs and the amplitude of the scattered signal can be explained taking into account the hieght profile of the atmosphere density. Most probably, the upper boundary of APIs in the D region is due to the increase in the atomic oxygen density and can serve as an altitude indicator.

Some results of measurement of atmospheric temperature and density using artificial periodic inhomogeneities of the ionospheric plasma

We present the preliminary results of measurement of atmospheric temperature and density at the E-region heights near Nizhny Novgorod in the 1990–1991 period (λ=56.15°N, ϕ=44.3°E). The monthly mean temperature and density are given in the height interval 100–110 km for September and October 1990. The temporal variations of temperature and density, associated with the propagation of acoustic-gravity and internal waves, are presented. The influence of natural turbulence on the measurement accuracy has been analyzed. The method is based on the generation of artificial periodic inhomogeneities (APIs) by a powerful radio wave and registration of the amplitudes of pulse probe radio waves backscattered by APIs.