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Information × Registration Number 0304U004194, 0103U004199 , R & D reports Title Particle flux and waves interaction with materials in problems of controlled thermonuclear synthesis popup.stage_title Поглинання поверхневих електромагнітних хвиль електронами у перехідному шарі діелектрик-плазма. Дослідження зміни властивостей оптичних матеріалів під дією факторів плазми Head Lapshin V.I., Registration Date 26-03-2004 Organization Kharkov National University named after V.N.Karazin popup.description2 Object of research - transient layer dielectric - plasma, magnesium aluminate spinel single crystals of different compositions MgOЧnAl2O3 (n=1.0 and 2.5). The purpose of activity - to study the influence of the Debye layer on the absorption of the surface electromagnetic wave at its propagation along the interface dielectric - plasma, to find the distribution of the electrical field in the Debye layer and absorption of energy of the wave in this layer by electrons of plasma, to investigate the optical absorption in magnesium aluminate spinel single crystals of different compositions after neutron, X-ray and UV irradiation. Method of research - to study the influence of the Debye layer on the absorption of the surface electromagnetic wave at its propagation along the interface dielectric - plasma the kinetic theory of high frequency oscillations of free plasma is utilized. To determine the potential of plasma the Poisson equation is utilized, the Maxwell - Boltzmann distribution was applied to find thecorrection to the distribution function of electrons, the distribution of the electromagnetic field of the surface wave was obtained by solving the set of Maxwell equations, to estimate the damping of the surface wave the energy conservation law is utilized. While solving this problem the integral equation is derived that allows determining the component of the electrical field of the surface wave that is normal to interface dielectric - plasma. This equation is resolved with the help of a computer. The numerical calculation also is used for finding the absorption coefficient of the surface wave. Magnesium aluminate spinel single crystals MgOЧnAl2O3 of different compositions (n=1.0 and 2.5) were grown by Verneuil method using pure green materials. Optical absorption was neasured in the range of photon energy 1.2-6.6 eV by using single or dual-beam spectrophotometers. Irradiation was provided with X-ray tube of copper anode at voltage 40 kV and currant 10 mA or deuterium lamp of 400 W power. There were provided detail investigations of absorption spectra in magnesium aluminate spinel single crystals subjected to UV, X-ray or neutron irradiation. By variation of irradiation time and using isochronal annealing there were found additional absorption bands at 4.15 eV for MgOЧ1.0Al2O3 crystals and 4.46 eV MgOЧ2.5Al2O3 crystals. From consideration of value of energy shift this absorption band, their high intensity, this band in nonstoichiometric spinel crystals could be identified with electron center related to the lattice defects. The outcomes of this activity can be utilized in devices and equipment, where the surface electromagnetic waves are present, which propagate along an interface dielectric - plasma, and also for the diagnostics of plasma. Product Description popup.authors popup.nrat_date 2020-04-02 Close