East European Journal of Physics

5

Authors: I. M. Pankratov, V. Y. Bochko

The energy of disruption generated runaway electrons can reach as high as tens of megaelectronvolt and they can cause a serious damage of plasma-facing-component surfaces in large tokamaks like International Thermonuclear Experimental Reactor (ITER). The synchrotron radiation diagnostic allows a direct observation of such runaway electrons and an analysis of their parameters and promotes the safety operation of present day large tokamaks and future ITER. Only this diagnostic will be applied in ITER. In the paper detail analysis of the synchrotron radiation spectra of runaway electrons for the recent Experimental Advanced Superconducting Tokamak (EAST, Institute of Plasma Physics of Chinese Academy of Sciences) experiment parameters has been presented. The calculations are carried out on the base of precise expression for synchrotron radiation spectral density. They make more precise spectra analysis of the previous paper by Zhou R.J., Pankratov I.M., Hu L.Q., et al. (Physics of Plasmas, 2014, Vol. 21, No. 6, 063302). Obtained results are important for correct interpretation of runaway EAST experiments and runaway experiments in other tokamaks.

5

Authors: V. G. Kirichenko, V. A. Kobylnik, T. A. Kovalenko, O. A. Usatova

The study of phase transformations in intermetallic phases, which are released in the form of fine-dispersed inclusions in binary alloys based on zirconium Zr - 1.03 at. % Fe; Zr - 0.51 at. % Fe; after ion irradiation and subsequent isothermal annealing was carried out. Mössbauer spectroscopy on 57Fe nuclei in backscattering geometry with registration of internal conversion electrons, X-ray spectral analysis, X-ray diffraction analysis and electron microscopy were used. As a result, the observed segregation and phase composition of the intermetallic phases in the surface layer change under ion irradiation. Subsequent isothermal annealing after irradiation leads to a change in the concentration of inclusions of intermetallic phases and phase modification in the surface layer.

6

Authors: O. A. Bizyukov, O. D. Chibisov, O. I. Kutenko

The evaporation possibility of micro sized metallic particles during them passage through the region of a magnetized plasma with a Maxwellian velocity distribution with the electron temperature in the range Te=1...100eV at presence of an ion beam with the energy in the range εb=1...6keV is studied theoretically. The floating potential of a macroparticle is obtained using the OML theory, the effect of the electron temperature and the energy of the ion beam on its magnitude is studied. The equation of energy balance on the macroparticle surface is obtained, such energy exchange mechanisms as collisions of particles of an ion beam and plasma particles with the macroparticle, thermal radiation of the macroparticle, as well as cooling due to the evaporation of substance from the macroparticle surface are taken into account. The effect of the temperature of plasma electrons and the ion beam energy on the stationary temperature of the macroparticle is studied. It is shown that for the given plasma and ion beam parameters, the temperature of the copper macroparticle is below the boiling point so that the evaporation of the macroparticle occurs at temperatures below the boiling point. The dependences of the macroparticle evaporation time on the electron temperature and the energy of the ion beam have been obtained.

7

Authors: V. M. Svishch

The entrainment of the light flux by a uniaxial anisotropic medium and its influence on the measurement of stellar aberration are analyzed. The influence of the entrainment of the light flux by an isotropic medium on the measurement of stellar aberration was considered by Fresnel early. The absence of such influence was confirmed by Erie's experience when filling the telescope tube with water. The formula itself was perfectly confirmed by Fizeau's experiments with moving water and the repetition of this experiment with an increase in the accuracy of measurements by Michelson, Zeeman, and others. G.A. Lorentz already on the basis of the electromagnetic theory specified the formula with allowance for the frequency dispersion of the light flux. A. Einstein made an analysis of the schemes of experiments for determining the drag coefficient, covering all possible variants of similar experiments. As a result, he obtained Fresnel and Lorentz formulas, taking into account the frequency dispersion of light, starting from the theory of relativity. The entrainment of light and its influence on the measurement of stellar aberration by a uniaxial anisotropic medium have not been considered anywhere. An analysis of such influence is carried out. The results of the analysis indicate the possibility of measuring the current value of stellar aberration using a uniaxial anisotropic medium. The concept of active light aberration is introduced. The proposed schemes of experiments of using the entrainment of a light flux by an anisotropic substance for measuring the current value of stellar aberration are investigated. It is concluded that it is possible to study the determination of the current velocity of an inertial system relative to the light flux.

7

Authors: P. I. Gladkikh, A. A. Kalamaiko, I. M. Karnaukhov

NESTOR is the hard X-ray source that is under commissioning at NSC KIPT. NESTOR based on the Compton scattering of laser photons on relativistic electrons. The structure of the facility can be represented as the following components: a linear accelerator, a transport channel, a storage ring, and a laser-optical system. Electrons are stored in the storage ring for energy of 40-225 MeV, laser photons are accumulated in the optical resonator. The frequencies of laser and electron bunches are synchronized, the interaction point located in the optical resonator. The measurements showed that parameters of the manufactured bending magnets different from the design ones. The bending magnets have different field index, besides the vertical focusing forces are significantly lower than designed ones. The beam dynamics simulation showed that due to decreasing of the vertical focusing the vertical betatron frequency becomes close to the frequency of the integer resonance Q = 2, as a result the vertical motion in the ring is unstable [1]. The second reason for optimization is the need to increase the length of the drift space for optical resonator. The results of optimization are presented in this paper.

8

Authors: K. Vus, U. Tarabara, K. Semenova, V. Viter, O. Nikitina, V. Trusova, G. Gorbenko

The applicability of Auramine O to the detection and characterization of lysozyme and serum albumin amyloid fibrils has been assessed using the fluorimetric titration and molecular docking. The parameters of the dye binding to native and fibrillar proteins were estimated in terms of the Langmuir adsorption model. It was found that Auramine O displays the high affinity for amyloid fibrils, being of the same order of magnitude as that of the classical amyloid markers. The dye also showed greater fluorescence response to lysozyme fibrils and lower sensitivity to the native protein, than Thioflavin T. Furthermore, unlike Thioflavin T, Auramine O was able to detect the morphological differences between lysozyme and albumin fibrils due to the shifts in the position of the emission maxima of the fibril-incorporated fluorophore. The molecular docking studies revealed that Auramine O and Thioflavin T form the most stable complexes with the G54_L56/S60_W62 groove of lysozyme fibrils, running parallel to the fibril axis. The results obtained suggest the contribution of both hydrophobic and electrostatic interactions to the stabilization of the dye complexes with amyloid fibrils.

14

Authors: Yu. M. Poluektov, A. A. Soroka

For the ideal Fermi gas that fills the space inside a cylindrical tube, there are calculated the thermodynamic characteristics in general form for arbitrary temperatures, namely: the thermodynamic potential, energy, entropy, equations of state, heat capacities and compressibilities. All these quantities are expressed through the introduced standard functions and their derivatives. The radius of the tube is considered as an additional thermodynamic variable. It is shown that at low temperatures in the quasi-one-dimensional case the temperature dependencies of the entropy and heat capacities remain linear. The dependencies of the entropy and heat capacities on the chemical potential have sharp maximums at the points where the filling of a new discrete level begins. The character of dependencies of thermodynamic quantities on the tube radius proves to be qualitatively different in the cases of fixed linear and fixed total density. At the fixed linear density these dependencies are monotonous and at the fixed total density they have an oscillating character.