FSUE FNPTS NIIIS named after Yu.Sedakov (Russia)

Background. The generation and development of experimental facilities for research in the field of near-Earth plasma physics is an extremely urgent task. The Sura short-wave heating stand is the only operating mid-latitude research facility in the world on the active effect on the Earth’s ionosphere. The new physical results obtained at the HAARP, which has a higher transmitter radiation power, stimulate work to assess the possibilities of upgrade and determine the achievable parameters of near-Earth plasma perturbations for other facilities including the Sura stand. Aim. Numerical simulation and analysis of achievable parameters of large-scale thermal disturbances of near-Earth plasma during facility upgrading and promising power levels implementation of the Sura stand. Methods. The simulation was conducted using open source SAMI2 code supplemented by an upgraded heating source model using direct calculation of the abnormal absorption coefficient to approximate the cold plasma at the Gaussian spectrum of elongated inhomogeneities. Results. Exposure results for both daytime and late evening hours were investigated. For daytime conditions it was obtained that the promising power levels implementation at the Sura facility results in an almost twofold increase of the density and electrons temperature perturbations in the artificial duct region at the Earth’s outer ionosphere heights. For late evening conditions it is obtained that the upgrade of the heating facility also results in a twofold increase of electron temperature perturbations. At the same time, the increase of the electron density relative perturbations level is not so significant and at most 20% relative to the actual facility characteristics. Conclusion. It has been shown that the generated thermal perturbation parameters are non-linearly dependent on the radiation power of the pump wave and their growth is saturated due to the plasma redistribution in the abnormal absorption region.

The results of the study of strip parametric passive radio transponders are presented. Stripline parametric passive radio transponders are made in the form of a system of three parametric generators connected to the pump signal strip antenna and the response signal strip antenna. The results of numerical and field experiments are presented for a pump signal frequency of 800 MHz and a response signal of 400 MHz, which are in good agreement.

Experimental results on selective excitation of improper waves and leaky wave of a round open dielectric waveguide are obtained using an example of the E01 leaky wave.

The change in the carrier mobility in GaAs structures after irradiation is numerically simulated. For each investigated scattering potential, the model parameters are determined at which the calculation data are consistent with the results of the experiment. It is shown for the first time that the form of the potential of scattering at radiation-induced defects determines the time and space dynamics of the velocity overshoot in short structures.

In this paper we present the results of development of the optocouplers for secondary power supplies. The dies of the optical radiation emitters are based on double heteroepitaxial AlGaAs structures, and the dies of the radiation receivers are based on silicon-on-sapphire. Dies were bonded to metal-ceramic packages using the optically clear silicone-organic adhesive. The results of the optocoupler testing showed the level of resistance to γ-neutron radiation, which meets the requirements for radiationresistant devices used in control and communication systems.

Excitation experiment technique of the E01 leaky wave in a round open dielectric waveguide is given. Experimental research results of the E01 leaky wave characteristics of a round open dielectric waveguide are presented.

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It is proposed that the Poole–Frenkel effect be applied to predict radiation-induced charge accumulation in thermal silicon dioxide. Various conduction mechanisms of thermal silicon dioxide are considered, the conditions of the appearance of the Poole–Frenkel effect in it are determined, and the characteristics of donor centers participating in Poole–Frenkel electrical conductivity are calculated. A donor center level at an energy of 2.34 eV below the conduction-band bottom is determined and the concentration of ionized donor centers of 1.0 × 109 cm–3 at 400 K and a field strength of 10 MV/cm is found. It is concluded that the Poole–Frenkel effect can be applied not for prediction of the absolute value of the radiation-induced charge but for comparison of the samples in terms of the ability to accumulate it.