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Information × Registration Number 0208U004863, 0106U001575 , R & D reports Title Interaction of electromagnetic waves and particles fluxes with materials in plasma installations popup.stage_title Head Girka Igor Olexandrovich, Registration Date 23-12-2008 Organization Kharkov national university named after V.N. Karazin popup.description2 The objects of the investigation are the impurity transport at plasma periphery of the toroidal magnetic devices and changes of properties of dielectric materials at the action of high temperature in different media. The aims of the investigation research are the role of the plasma ELM- activity and the magnetic resonance structures in the impurity transport at the plasma periphery as well as influence of high temperate annealing of spinel crystals in reduced, oxidized, and neutral media on the physical properties of this material. Method of investigations: The particle motion near the resonance point has been analyzed by the numerical integrating of the guiding center equations. The analytical treatment of the resonance condition "particle- magnetic field perturbation" has been done. The semianalytical research methods, which are based on the formation of the drift resonances due to the resonance magnetic perturbations of the particular mode, have been developed. This consideration operates with modeling of the Larmor radius of a single particle. In the framework of this consideration the nonideal MHD theory is also complemented by the analysis of the single particle motion. The processes taking place at the annealing at high temperature in reduced or oxidized atmospheres, the change of composition, structure, optical and mechanical properties of spinel crystals were investigated by the methods of optical spectroscopy, X-ray diffractometry, radioluminescence and optical microscopy. From the first D-T experiments on JET and TFTR it became obvious that large MHD activity causes a fast ion loss fraction up to ? 50%, which would be intolerably large for a reactor [2]. As it was shown analytically in [3] resonant interaction between a spectrum of Alfven waves and ?-particles can take place, leading to significant anomalous transport of the particles. The resonant interaction is also very important for helical systems, because spectrum of these phenomena is wider due to helical symmetry. A lot of experimental investigations on tokamaks are devoted to decreasing heat load on plasma faced components of the divertor and controlling impurity transport at plasma edge. The solution to the problem of the resonant interaction right now does not give the answers on the many questions concerning the relations between the amplitudes, phases and frequencies of the observed magnetic field perturbations and particle fluxes. There were investigated spinel crystals of different compositions MgO·nAl2O3 of n=1.0 and 2.5 after annealing in vacuum, hydrogen, and oxygen of different prolongation at variation of temperature. There were obtained data on the optical absorption, radioluminescence, lattice parameter and mechanical properties. After annealing in vacuum and hydrogen the crystals are more ordered as compared with untreated ones. Non-stoichiometric crystals MgO·2.5Al2O3 annealed in hydrogen have much higher concentration of anionic vacancies which leads to formation of additional hole and electron centres. Annealing in the oxygen atmosphere causes the extraction from surface layer primarily magnesium oxide and transformation of non-stoichiometric spinel into ?-Al2O3. This fact was proved by investigation of radioluminescence spectra in which the bands at 280 and 320 nm were observed which are related to F and F+centres in ?-Al2O3 and also emission lines of Mn2+ and Cr3+ -ions in ?-Al2O3. In X-ray-structure analysis there appear the reflection lines which undoubtedly belong to ?-Al2O3 phase. According to the technical recommendations we concluded that physical properties of stoichiomentric spinel crystals are more resistant to influence of different aggressive media as compared with non-stoichiometric ones. The results of this project can be used at the investigation of problems of the controlled thermonuclear fusion in the Institute of Plasma Physics at National Science Center "Kharkiv Institute of Physics and Technology". Results can be used also for analysis of experiments at tokamaks, particularly at Joint European Torus (JET),and torsatrons such as Large Helical Device (LHD). Results on the change of parameters of crystals and ceramics at the action of different atmospheres and temperature can be used for prediction of changes in properties of materials at the influence of plasma factors. Product Description popup.authors popup.nrat_date 2020-04-02 Close