Vestnik NSU. Series: Physics. 2014. V9, i 3

Quantum Optics, Quantum Electronics

S. A. Frolov, V. E. Leschenko, V. I. Trunov. MODEL OF LUMINESCENCE EVOLUTION IN HIGH-POWER LASER SYSTEMS BASED ON PARAMETRIC AMPLIFICATION CASCADES
The paper presents the model of parametric luminescence evolution that takes diffraction, birefringence and group velocity dispersion into account. The distinctive feature of the model is capability to compute full frequency-angular spectra of amplified luminescence generated during parametric amplification of chirped pulses. That allows not only to compute pulse contrast but also to estimate influence of superluminescence on energy of amplified pulses. The results of experiments to measure parameters of parametric luminescence generated during parametric amplification of chirped femtosecond pulses in BBO crystals are presented. The comparison of experimental and simulation results shows good agreement between theory and experiment.

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Radiophysics and Electronics

P. V. Zubarev, S. V. Ivanenko, A. A. Ivanova, A. N. Kvashnin, A. I. Kotelnikov, E. A. Puryga, A. D. Khilchenko, V. G. Shvyrev. DIGITAL ANALYZER OF DIAMOND DETECTOR SIGNALS FOR ITER VERTICAL NEUTRON CAMERA
In this paper, digital analyzer of diamond detector signals of ITER Vertical Neutron Camera (ITER VNC) are described, which uses digital signal processing. Digital analyzer of pulse signals is based on ADC12500PXIe (two channels,
12 bit, 500 MHz, PXI Express), which satisfies the ITER VNC requirements. In this paper, the architecture of digital signal processing unit is given. Trapezoidal digital shaper for pile-up separation and energy spectrum unit are described. In addition, structure of digital analyzer software levels are considered.

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P. A. Bak, A. V. Ottmar, D. A. Starostenko. ALTERNATIVE TECHNIQUE OF INVERTER POWER SOURCE SYNCHRONIZATION
In devices synchronized with electric mains and sensitive to interference (particularly to an inverter power source) it is expedient to also synchronize the power source. The paper describes a method of synchronizing the inverter power supply with the mains. The general aspects of the method are discussed in detail, and possible hardware implementations are considered. External factors and internal parameters affecting the quality of synchronization are analyzed. The results of practical implementation of this method for synchronization of klystron filament power supply are presented.

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Physics of Field, Neutral and Ionized Gases

A. V. Boiko, A. V. Dovgal, A. M. Sorokin. LAMINAR BOUNDARY LAYER SEPARATION AFFECTED BY A LOCAL TEMPERATURE PERTURBATION
Backward-facing step flow with laminar boundary layer separation forced by a local stationary temperature disturbance was experimentally investigated. The results of the study were obtained in quiet wind-tunnel conditions at low subsonic flow velocity. To generate the temperature perturbation, the test model was equipped with a Peltier element placed flush with the wall before the line of separation. At first, the hot-wire technique was adapted to examine the flow with temperature gradients; then, the velocity characteristics were determined making clear the effects of heat transfer on boundary layer separation.

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B. Yu. Zanin, M. M. Katasonov, M. V. Mikhaelis, A. M. Pavlenko. EXPERIMENTAL STUDIES OF THE EFFECT OF VORTEX DISTURBANCES ON THE FLOW AROUND THE WING MODEL AT LOW REYNOLDS NUMBERS
Results of experimental investigations in subsonic wind tunnels, which studied the impact of artificial forcing on the flow in the boundary layer of straight wing model were described. The feature of this work is the use of such locally impact that can change the general flow pattern. The influences of the angle of attack, free stream turbulence level, and wake behind thin thread on the flow near the wing profile were studied at this paper. The method of oil-film based on titanium dioxide was applied for flow visualization, also hot-wire measurements were used. The obtained results were analyzed with the aim of finding the most efficient ways of vortex control to the flow.

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E. S. Gesheva, S. I. Shtork, S. V. Alekseenko. INVESTIGATION OF CHARACTERISTICS OF CONCENTRATED VORTEX IN THE TANGENTIAL CHAMBER USING PIV TECHNIQUE AND COMPUTER SIMULATION
The work is focused on a detailed study of the characteristics of the vortex flow in the chamber tangential type, modeling, in particular, the common furnace coal-fired boilers. It was shown that the vortex structure formed in the chamber
with diaphragm is a vortex filament with the relative radius rm / R = 0,1 and a length of about the size of the camera l / R = 6. During researches it was measured the velocity field and vortices using a static method of diagnosis flow PIV,
and performed the verification of calculated data obtained using the LES and DES methods for simulation of turbulent flows in the CFD package Star CCM +. Calculated velocity profiles and vortex precession frequency agree with experimental data, which indicates the correctness of chosen approach of modeling of turbulent swirling flow.

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I. E. Gerasimov, D. A. Knyazkov, A. G. Shmakov, O. P. Korobeinichev N. Hansen, C. K. Westbrook. INVESTIGATION OF METHYL PENTANOATE FLAME STRUCTURE BY MOLECULAR-BEAM MASS SPECTROMETRY AND MODELING
The structure of four stoichiometric and fuel-rich premixed flames of methyl pentanoate stabilized at low (20 torr) and atmospheric pressures has been studied by molecular-beam mass spectrometry. The data obtained have been compared with results of numerical simulations, performed with implication of two detailed chemical kinetic mechanisms, one of which has been developed by the authors of this work. While both mechanisms have predicted concentration profiles for most of the species quite well, some discrepancies between experimental and modeling data have been observed for carbon monoxide and some intermediate products. Considerable differences in several profiles simulated with different mechanisms have been noted. Analysis of reaction paths in investigated flames has shown most of these differences to be caused by different reactions and kinetics used for isomerization of primary radicals of methyl pentanoate oxidation in these mechanisms.

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V. S. Berdnikov, K. A. Mitin, A. V. Mitina. CONJUGATE HEAT TRANSFER U-SHAPED SILICON ROD WITH THE ENVIRONMENT WITH GAS THERMOGRAVITATIONAL CONVECTION
The conjugated natural convective heat transfer of electrically heated U-shaped silicon rod which placed in a rectangular container filled with gas with isothermal cold walls was numerically studied in a three-dimensional formulation of the problem. The temperature was maintained constant at the control point which placed on a surface of the U-shaped rod by selection of voltage. Temperature difference between the control point and the cold walls is 70 K. The equations of natural convections in Cartesian coordinates with Boussinesq approximation in terms of temperature, vortex and vector potential of velocity field were solver by FEM. Convective flows spatial form and temperature fields inside gas and the solid were investigated.

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Solid-State and Semiconductor Physics, Physics of Nanostructures

A. S. Krinitsyn, I. V. Tikhomirov, K. N. Yugay. THE TEMPERATURE OF BEREZINSKY – KOSTERLITZ – THOULESS TRANSITION IN TWO-DIMENSIONAL SUPERCONDUCTOR IN AN EXTERNAL FIELD
The Method of Monte-Carlo calculated temperature of Berezinsky – Kosterlitz – Thouless transition in twodimensional superconductor 2nd type in the presence of an external magnetic field. It is shown that near the upper critical
field filling cells with a size of ? x ? relation, where ? – coherence length at a given temperature, corresponds to half. It is also shown that ТBKT decreases with increasing interaction between the vortices and antivortices and increase of the external applied magnetic field.

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D. A. Yatsenko, S. V. Tsybulya. CALCULATION METHOD OF DIFFRACTION FROM ORDERED NANOPARTICLE ASSEMBLIES
Systems with an ordered (quasiordered) packing of nanosized particles or a regular arrangement of pores are specific objects of research for diffraction methods. Such organized systems (nanostructures) are often characterized by diffraction effects in the form of additional diffraction peaks depending on the type of packing. At research of the structured samples it is important to determine the nanostructure parameters and characteristics associated with the shape and sizes of the particles or pores. Approaches will be considered below, allow to determine the parameters of nanostructures from the diffraction data.

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Computer Science, Information-Communication Technologies

P. B. Cheblakov, A. A. Derbenev, S. E. Karnaev, A. V. Makeev. BASIC SOFTWARE FOR NSLS-II BOOSTER SYNCHROTRON MAGNETIC SYSTEM CONTROL
NSLS-II booster synchrotron magnetic system requires a specific control hardware and software. This article describes the control system as a whole and its concepts of operation. Principles of control were proposed and EPICS-based software was developed, permitting individual independent digital control of each power supply. This design provides precise alteration of power supplies operation in each synchrotron cycle with frequency of 1 or 2 Hz.

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