DRIFT TURBULENCE IN PLASMA OF LOWER HYBRID SOLITARY STRUCTURES IN THE EARTH’S IONOSPHERE

D.V. Chibisov

Full Text :   (370 kB, Rus.) 

Abstract
The linear and nonlinear stages of the drift instability in plasma of lower hybrid solitary structures that are observed in the Earth's ionosphere are investigated. Because these structures have axial symmetry, the analysis is based on the theory, which considers as elementary small-scale perturbations the cylindrical waves. It is shown that the linear stage of drift instability with an increase of oscillations amplitude changes to the nonlinear stage in a broad spectrum of the wave numbers. A quasi-linear stage of instability is considered, the estimates of turbulent diffusion of ions, which leads to the destruction of these structures, are performed.

KEY WORDS: lower-hybrid solitary structures, lower-hybrid cavities, ionosphere, the drift turbulence, turbulent diffusion.

PARTIAL HAMILTONIAN FORMALISM, MULTI-TIME DYNAMICS AND SINGULAR THEORIES

S. A. Duplij

Full Text :   (350 kB, Rus.) 

Abstract
In this paper we formulate singular theories (determined by degenerate Lagrangians)without involving constraints. We construct a partial Hamiltonian formalism in reduced phase space (with arbitrary number of momenta). The equations of motion are first-order differential equations, and they coincide with ones of the multi-time dynamics under a certain condition, which in a singular theory is coincidence of number of generalized momenta to the rank of the Hessian matrix. Non-canonical generalized velocities satisfy the system of linear algebraic equations, which sets the appropriate classificatio of singular theories (gauge and nongauge). To describe the time evolution of physical quantities we introduce a new anti-symmetric bracket (similar to the Poisson bracket). It is shown how the extension of the phase space leads to constraints, and the new bracket goes in to the Dirac bracket. Quantization is briefl discussed.

KEY WORDS: action, degenerated Lagrangian, Hamiltonian, Hessian, rank, Hamilton-Jacobi equation, many-time dynamics, bracket

NEUTRAL STRANGE HADRON PRODUCTION IN HEAVY ION COLLISIONS AT ENERGIES = 8,7-17,3 GEV

V.A. Kizka, A.Yu. Korchin, V.S. Trubnikov

Full Text :   (1300 kB, Rus.) 

Abstract
The data on the yield of neutral strange hadrons at the collisions of heavy ions(Au+Au, Pb+Pb) at energies = 8,7-17,3 GeV are presented. The ratios of yields of the neutral strange hadrons Λ⁰/K_S⁰ are compared for the different centrality collisions of heavy ions. The nuclear modification factor R_CP as function of transverse momentum for different colliding energies is investigated. The experimental results for Au+Au collisions at energy = 9,2 GeV are compared with the different theoretical models (UrQMD2.3, EPOS1.67, HIJING1.7), describing the dynamics of processes of heavy ions collision. It was shown that the model UrQMD2.3, describing heavy ion collisions without using partonic degrees of freedom being created in area of heavy ion interaction, gives better agreement with experimental data than the models EPOS1.67 and HIJING1.7 that use the partonic degrees of freedom.

KEY WORDS: neutral strange hadrons, nuclear modification factor, parton degree of freedom.

J-DEPENDENCE OF THE POLARIZATION OBSERVABLE OF STRIPPING REACTIONS AT LOW ENERGIES ON LIGHTWEIGHT NUCLEI

V.D. Sarana, N.S. Lutsay, N.A. Shlyakhov

Full Text :   (1400 kB, Rus.) 

Abstract
On the basis of consideration of change the pictures of angular dependences cross section, polarization and the vector analyzing power (VAP) of ⁹Be(d,p₀)¹⁰Be reactions the investigated interval of energy from 2,0 to 15,0 MeV is divided into three zones that have essential distinctive features: the 1st - "classical" from the point of view of behavior VAP and polarization, the 2nd - "abnormal" from the point of view of behavior of polarization, the 3rd - "double problems" from the point of view of behavior of polarization and energy dependence of the interferential pictures of the differential cross section. It is revealed parameterization of DWBA calculations that describes "abnormal" polarization in (d,p) reaction in the 2nd zone. J-dependence of polarization that differs from observed in the "classical" area is found. Using our experimental cross section and VAP data in the 3rd area for the analysis on optical model and DWBA, it is shown that along parameterization, found in the 2nd area, it is possible to reproduce simultaneously well the features of behavior of cross section, polarization and VAP in reaction ⁹Be(d,p₀)¹⁰Be and, using j-dependence VAP, for mixed on j transition ⁹Be(d,p₁)¹⁰Be* (3,37 MeV) absolute and relative spectroscopic factors close to calculated on shell model are found.

KEY WORDS: nuclear reactions, beryllium, stripping, cross section, VAP, proton polarization, DWBA, optical potentials, j-dependence

ANALYSIS OF SYNCHROTRON RADIATION EMITTED BY RUNAWAY ELECTRONS IN TOKAMAKS

M. Pankratov, I.V. Pavlenko, O.A. Pomazan

Full Text :   (1200 kB, Eng.) 

Abstract
The synchrotron radiation diagnostics allows a direct observation of the runaway electron beams and an analysis of their parameters. Strong oscillations of the instantaneous curvature radii of electron orbits were a characteristic feature of recent EAST and KSTAR tokamak runaway electron experiments. Incorrect analysis of synchrotron radiation spectra of runaway electrons was carried out by EAST team. In presented paper the detail theoretical analysis of the synchrotron radiation spectra of the runaway electrons which gyrate around their guiding centers in the curved magnetic field is presented for cases when the curvature radius of electron orbit oscillates strongly. Key parameter of the analysis is the ratio of the cyclotron rotation velocity to the velocity of the vertical centrifugal drift. This analysis is applied for correct calculations of synchrotron radiation spectra for EAST and KSTAR runaway electron parameters.

KEY WORDS: synchrotron radiation; runaway electrons; tokamak; curved magnetic field

INFLUENCE OF THE SAFETY FACTOR VARIATION ON EXCITATION OF RESONANT MAGNETIC PERTURBATION IN TOKAMAK ROTATING EDGE PLASMAS

I.M. Pankratov, I.V. Pavlenko, O.A. Pomazan, A.Ya. Omelchenko

Full Text :   (900 kB, Eng.) 

Abstract
Recently the possibility of resonant excitation of pressure perturbation by external helical magnetic perturbations near the rotating plasma edge was shown taking into consideration the finite plasma conductivity. In present paper the influence of the small safety factor variation on the pressure perturbation and on the plasma current response is studied. This phenomenon may explain the existence of the small window of safety factor values where ELMs were completely eliminated. The possibility to control the plasma current response to penetration of external helical resonant magnetic perturbations into the edge plasmas is shown. The investigation is carried out in the frame of one-fluid MHD.

KEY WORDS: resonant magnetic perturbations; edge localized modes; plasma rotation; plasma conductivity; tokamak.

WAVES OF MAGNETIZED PLASMA-FILLED WAVEGUIDE WITH ZERO VALUE OF EITHER OF TWO TRANSVERSE WAVENUMBERS

V.I. Shcherbinin, V.I. Tkachenko

Full Text :   (900 kB, Eng.) 

Abstract
This paper describes the electromagnetic properties of the waves in a magnetized plasma-filled waveguide with one transverse wavenumber being equal to zero. It was found, that despite zero denominators of the field expressions for such waves, the validity of these expressions is not violated. As a result it was shown that the wave frequency and field change continuously when one of its transverse wavenumbers crosses zero. It was also found, that the point of such crossing changes with the sign change of the wave azimuthal index.

KEY WORDS: plasma-filled waveguide, magnetized plasma, dispersion equation, eigenfrequencies, eigenfields

ON OPPORTUNITY OF DROPLET SPUTTERING OF HEAVY METALS BY HEAVY IONS OF LOW AND INTERMEDIATE ENERGIES

A.I. Kalinichenko, S.S. Perepelkin, V.E. Strel’nitskij

Full Text :   (500 kB, Rus.) 

Abstract
A droplet sputtering of heavy metals by heavy ions in energy range of elastic loss domination is theoretically investigated. It is shown that the droplet sputtering is possible at ion energies E both below and above the maximum permissible energy of nonlocal thermoelastic peak (NTP_<) formation - a singly connected overheated region approximated by spherical segment. At E < E_NTP melt emission from subsurface NTP_< is possible in the range of ion energies E₁<E<E₂, and quantity E₁ and E₂ depend on sort of bombarding ions and structure of target material. At E > E_NTP the droplet sputtering provides nonlocal thermoelastic peak (NTP_>), forming from subsurface subcascade and/or on cross of several subsurface subcascades. Localization, size and energy content NTP_>, being random quantities, were determined by modeling with program package SRIM2008. Parameters and probability of NTP_> forming, providing the droplet sputtering and cratering are determinated at ion energies E = 200 keV in cases of combinations "ion Au+ in Au" and "ion U+ in U". Estimates of sputtering yields of droplet sputtering are determinated in the viewed cases.

KEY WORDS: heavy metals, ion bombardment, atomic cascade, thermoelastic peak, droplet sputtering, cratering

EFFECT OF THE FLAT ELECTRODE DIAMETER ON THE IGNITION AND BURNING OF DC DISCHARGE

V.A. Lisovskiy, V.V. Malinovskiy, V.A. Derevyanko

Full Text :   (1200 kB, Rus.) 

Abstract
This paper studied the effect of electrode diameter (55 mm, 25 mm, 12 mm, 5 mm, 2.4 mm and 0.8mm) on the ignition of the discharge in nitrogen and its modes of burning at a distance between electrodes 25 mm. The decrease in the electrode diameter was found at large gas pressures to discharge ignition at lesser voltages than for large size electrodes and at low gas pressures to the shift of breakdown curves to higher breakdown voltages. We revealed that all breakdown curves we had registered intersected at the nitrogen gas pressure value of p ≈ 0.9 Torr close to the inflection point of the breakdown curves for large electrodes. To the left of the inflection point the distortion of the uniform distribution of the electric field between the electrodes of moderate diameter impedes the ionization multiplication within the discharge gap and the breakdown voltage grows, and to the right of the inflection point the conditions for gas breakdown became easier to meet due to the redistribution of the electric field. We found that the expanding discharge spot quickly covered all surface of moderate size electrodes, therefore the normal mode might be observed within a narrowing range of discharge current, whereas the decrease in the electrode diameter lowered the growth rate of the discharge current with the voltage increasing. We employed the dogleg feature of the current-voltage characteristics to determine the ratio of the normal current density to the gas pressure squared for different electrode diameter and gas pressure values to be about (J/p²)n ≈ 0.233 mA/(cm·Torr)² what was in good agreement with the results of other authors.

KEY WORDS: DC glow discharge, the diameter of the electrode, the ignition of the discharge, normal mode, abnormal mode, the normal current density.

THE CHILD-LANGMUIR COLLISIONAL LAWS FOR THE CATHODE SHEATH OF GLOW DISCHARGE IN NITROGEN

V.A. Lisovskiy, V.A. Derevyanko, V.D. Yegorenkov

Full Text :   (1600 kB, Rus.) 

Abstract
This communication reports the measurements of dc sheath thickness d together with the voltage drop U across it at different current I values in nitrogen. For the case of a narrow gap when the discharge consists only of a cathode sheath and a negative glow almost all voltage applied across the electrodes drops across the cathode sheath. We observe that at the nitrogen pressure p < 1 Torr, as well as for p > 1.5 Torr the Child-Langmuir collisional law version characterized by the constant ion mobility is valid. Within the pressure range of 1 < p < 1.5 Torr none of Child-Langmuir law versions (with a constant mobility or a constant ion mean free path) are not applicable for the description of the dc cathode sheath in nitrogen. The available references enable us to conclude that at p < 1 Torr the discharge is dominated by N⁺ ions whereas for p > 1.5 Torr N₄⁺ ions dominate. These ions are not prone to charge exchange with N₂ molecules and they move in the dc cathode sheath with constant mobility. Within the pressure range of 1 < p < 1.5 Torr the discharge contains N⁺, N₂⁺, N₃⁺ and N₄⁺ ions in comparable concentrations therefore none of the Child-Langmuir law versions can be valid.

KEY WORDS: glow discharge, the cathode sheath, positive ions, nitrogen, the Child-Langmuir law

PHOTOLUMINESCENCE AND CATALYTIC PERFORMANCE OF GAMMA ACTIVATED ZNO NANOPARTICLES

N.P. Dikiy, A.N. Dovbnya, E.P. Medvedeva, I.D. Fedorets, N.P. Khlapova, Yu.V. Lyashko, D.V. Medvedev

Full Text :   (900 kB, Rus.) 

Abstract
A methanol conversion on γ-activated nanoparticles of ZnO is investigated at room temperature through the example of a model reaction. Activation of nanoparticles of ZnO is carried out by slowing-down γ - radiation on the high-current electronic accelerator in NSC KIPT at energy of electrons 22 MeV and a current 500 mА. An element composition, crystallinity and character of an intermolecular interaction in samples of activated and initial nanoparticles of ZnO are studied by the methods of γ-spectroscopy, X-ray diffraction and IR-spectroscopy. The transformations were analysed and it was shown that there were no essential changes in the structure of ZnO: activated nanoparticles of ZnO maintained the monophase state and crystallinity of the initial state. The energy band diagram of nanoparticles of ZnO explains the photoluminescence results. Measurements of photoluminescence allow to suppose that the observed increase in intensity of luminescence in a case of γ-activated nanoparticles of ZnO is attained by a mutual amplification of the highly active oxygen superficial centers action and Auger electrons from ⁶⁵Zn. A considerable increase in catalytic activity of ZnO after its γ-activation is ascribed to the synergy of factors of ionizing radiation - noticeable ionization losses of Auger electrons near the surface of ZnO nanoparticles from ⁶⁵Zn - and influence of high-reactionary formations of a heterogeneous catalysis.

KEY WORDS: nanoparticles ZnO, electron accelerator, gamma-activation, X-ray diffractometry, IR-spectroscopy, methanol conversion, catalytic activity of ZnO

THE ENERGY RESOLUTION OF THE X-RAY SPECTROMETER WITH SI(LI) DETECTOR

D.A. Sanzharevsky, V.A. Stratienko, A.V. Shchagin

Full Text :   (800 kB, Rus.) 

Abstract
Results of experimental research of the energy resolution of the X-ray spectrometer based on cooled Si(Li) detector against from the energy of the incident photons are presented. The experimental data on the energy resolution are compared to results of calculated data. The Fano factor of the detector and the noise of the electronics are determined. Analytical expression for description of the energy resolution of the spectrometer in the range from about 1 to about 100 keV is found.

KEY WORDS: X-ray radiation, X-ray detector, Fano factor, energy resolution

THE STRUCTURE AND EPR OF THE LOWSIZE POWDERS KNb_1-xFe_xO₃

I.S. Golovina, V.Е. Rodionov, S.A. Haynakov, V.V. Lytvynenko

Full Text :   (1300 kB, Rus.) 

Abstract
The compounds of KNb_1-xFe_xO₃ system (at 0.01 < х < 0.8), synthesized by a technique of oxidation of metal in molten potassium nitrate with the addition of potassium hydroxide, have been investigated by means of XRD, SEM and EPR methods. Homogeneity range and solubility limit of iron have been established. The XRD data showed that in the compositions with x>0.2, in addition to the solid solution, an impurity phase α-Fe₂O₃ is emerged. In the EPR spectra even at х=0.05, a ferromagnetic resonance signal at g=2.004 is registered, which presumably also corresponds to α-Fe₂O₃ phase. In the compositions with x=0.1 and above, another ferromagnetic signal at g≈15 arises, which may corresponds to the formation of α-Fe clusters.

KEY WORDS: potassium niobate, nanopowders, phase composition, electron paramagnetic resonance

PECULIARITIES OF HYDROGEN SORBTION BY METAL-HIDRIDE IN PLASMA OF GLOW DISCHARGE

I.N. Sereda

Full Text :   (330 kB, Rus.) 

Abstract
The paper is devoted to experimental investigations of the processes peculiarities of hydrogen absorption and desorption by getter hydride-forming Zr₅₀V₅₀ alloy in plasma of glow discharge. Such a way creates a possibility to make reactions that using common methods is only at extreme conditions. In this work the conditions of hydrogen absorption by such alloys in glow discharge were determined. The correlation between the absorbed hydrogen quantity depending on external discharge parameters and desorbed hydrogen quantity were carried out.

KEY WORDS: metal-hydride, glow discharge, sorption-desorption of hydrogen, mass-spectrometry, plasma

MATERIALS ON THE BASIS OF ZIRCONIUM FOR CREATING OF MEDICAL IMPLANTS

M.M. Pylypenko, A.A. Drobyshevskaya, R.V. Azhazha, Yu.S. Stadnik, I.G. Tantsyura, D.V. Kovteba

Full Text :   (2300 kB, Rus.) 

Abstract
The aspects of production workpieces from zirconium and alloy Zr1%Nb using high temperature deformation for medical implants are considered, their physical and mechanical properties are studied. The results of the temperature effect on the formation of the oxide film on the surface of these materials are presented. The changes in the structure and properties of zirconium workpieces due to exposure of thermal treatment in the air up to 800 °С are analyzed.

KEY WORDS: zirconium, zirconium alloy, properties, structure, metal implants

THE ANALYSIS OF THERMAL REGIMES OF SPENT NUCLEAR FUEL STORAGE AT ACCIDENT CONDITIONS

S.V. Alyokhina

Full Text :   (600 kB, Rus.) 

Abstract
The expected accident conditions with blocking of ventilated channels of spent nuclear fuel storage containers on Zaporizhska NPP were considered. By solving of conjugate heat transfer problems the maximal temperatures inside containers at each of considered accidents were calculated. On base of received results the system of accidents gradation was proposed.

KEY WORDS: spent nuclear fuel, dry storage, conjugate heat transfer problem, thermal state, design basis accident.