N. V. Bakhmet'eva

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.

Investigation by backscatter radar of artificial irregularities produced in ionospheric plasma heating experiments

Abstract The artificial ionospheric turbulence occurs in the ionosphere illuminated by high power HF radio waves. There are a lot of irregularities stretched along the geomagnetic field in this region. The investigation of the artificially disturbed ionospheric region is based on the reception of back scattered signals (BSS) which permits the basic parameters of this region to be estimated and its inhomogeneous structure to be described. Experiments were carried out using ‘Sura’ heating facility in the frequency range of ƒ = 4.7–9 MHz (ordinary mode) with the effective radiated power Peff = 50–70 MW beamed vertically upwards. The most important dynamic and statistical BSS characteristics (the built-up time, the relaxation and autocorrelation times, the BSS amplitude spatial correlation function and power spectra) were measured using probe waves in the frequency range of ƒ p = 1.68−6 MHz that made it possible to obtain the basic parameters of the artificial irregularities. The model representation of a disturbed region in a form of a periodic structure gives a possibity to evaluate the scale of the structure, the whole size of the disturbance and its power and to calculate the main BSS characteristics.

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.

Diagnostics of artificial ionospheric turbulence by oblique sounding

The authors present the results of experimental investigations of artificial moderate scale inhomogeneities in the ionospheric F-layer, produced by intense radio waves. The investigations were performed by means of multifrequency oblique sounding along two tracks with lengths of approx. 300 km. We determine the dimensions of the inhomogeneities which contribute maximally to the scattering of the radio waves along these two tracks. We investigate the spectral shape of the amplitude fluctuations.

Investigation of acoustic gravity waves in the upper atmosphere by the artificial periodic inhomogeneities method at Nizhny Novgorod

We present the results of observation of acoustic gravity waves in the height range 60–120 km. AGW were studied by means of plasma velocity measurements. The observations, based upon use of a newly-developed diagnostic technique, were carried out during September 1990–May 1991. The method uses the artificial periodic inhomogeneities (API) which occur in the ionosphere illuminated by high- power HF radio waves. This method, based upon measurements of phases of waves back scattered from API, has a time resolution sufficient to observe short-term variations in the atmosphere. Seasonal variations of daily averaged vertical velocities were obtained. Above the turbopause height upward vertical motions dominated. Wave-like oscillations in the vertical velocity, which are most probably caused by AGW, occurred.