SIBERIAN JOURNAL OF PHYSICS. Scientific Journal. 2021. V16, i 1

 

Quantum Optics, Quantum Electronics

 

Lizunov S. A., Zhukov V. P., Bulgakov A. V., Bulgakova N. M. A Numerical Study of the Dynamics of Gold Heating by Ultra-Short Dichromatic Laser Pulses // Siberian Journal of Physics, 2021, vol. 16, no. 1, p. 5–20. (in Russ.) DOI 10.25205/2541-9447-2021-16-1-5-20

The interaction of femtosecond laser pulses of moderate intensity with metals by the example of gold is studied. The main attention is paid to dichromatic regimes of laser irradiation corresponding to a new trend in the field of laser pro-cessing of materials. Based on the two-temperature approximation, a new model is created which involves a dichro-matic source of the laser radiation energy and also takes into account the influence of the electron temperature on the reflection coefficient of the irradiated material and thermophysical properties of its electronic subsystem. For numerical implementation of the model, an implicit divergent finite-difference scheme is created with an improved method for describing the melting process in comparison with previous works. The model calculations have shown that the absorption of the laser energy by gold depends on the sequence of two pulses at different wavelengths and the delay time between them, and for correct description of the absorbed energy, it is necessary to take into account the change of the reflection coefficient of the surface during irradiation. The developed model may be of interest for optimizing the processing of materials with ultra-short dichromatic laser pulses.

Keywords
laser processing of metals, ultra-short laser pulses, dichromatic radiation, optical properties, numerical simulation

Funding
The work was carried out within the framework of the state contract with IT SB RAS and with the support of the RFBR (project no. 19-38-90203)

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High-Energy and Accelerator Physics, Physics of High-Temperature Plasma

 

Shamanin I. V., Arzhannikov A. V., Prikhodko V. V., Shmakov V. M., Modestov D. G., Lutsik I. O., Polozkov S. D., Bedenko S. V. Hybrid “Fusion-Fission” Reactor Facility on Thorium Fuel with a Source of Additional Thermonuclear Neutrons // Siberian Journal of Physics, 2021, vol. 16, no. 1, p. 21–43. (in Russ.) DOI 10.25205/2541-9447-2021-16-1-21-43

The results of full-scale numerical experiments of a hybrid thorium-containing fuel cell facility operating in a close-to-critical state due to a controlled source of fusion neutrons are discussed in this work. The facility under study was a complex consisting of two blocks. The first block was based on the concept of a high-temperature gas-cooled thorium reactor core. The second block was an axially symmetrical extended plasma generator of additional neutrons that was placed in the near-axial zone of the facility blanket. The calculated models of the blanket and the plasma generator of D-T neutrons created within the work allowed for research of the neutronic parameters of the facility in stationary and pulse-periodic operation modes. This research will make it possible to construct a safe facility and investigate the properties of thorium fuel, which can be continuously used in the epithermal spectrum of the considered hybrid fusion-fission reactor.

Keywords
hybrid “fusion-fission” reactor, thorium-containing fuel, plasma pulse-periodic generator, repetitively pulsed operation, “wave” fission

Funding
This research was supported by RFBR, project no. 19-29-02005

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Physics of a Fluid, Neutral and Ionized Gases

 

Kocharin V. L., Semionov N. V., Kosinov A. D., Yatskikh A. A., Shipul S. A., Yermolaev Yu. G. Experimental Study of the Influence of Unit Reynolds Number on the Laminar-Turbulent Transition on the Model Swept Wing with a Subsonic Leading Edge at M = 2 //Siberian Journal of Physics, 2021, vol. 16, no. 1, p. 45–53. (in Russ.) DOI 10.25205/2541-9447-2021-16-1-44-52

Experimental studies of the influence of unit Reynolds number on the laminar-turbulent transition in a supersonic boundary layer of a swept wing with a subsonic leading edge at Mach number 2 are performed. The experiments were performed on a model of a swept wing with a swept angle of the leading edge of 72 degrees and with a 3% profile with a variable chord length in span. The hot-wire measurements showed that a laminar-turbulent transition in a supersonic boundary layer of a swept wing with a subsonic leading edge occurs earlier (~25-30%) than on a model with a supersonic leading edge with the same oncoming flow parameters. It is shown that a change unit Reynolds number insignificant influence the laminar-turbulent transition in the boundary layer of a swept wing with a subsonic leading edge.

Keywords
experiment, supersonic flow, laminar-turbulent transition, turbulence, boundary layer, swept wing

Funding
The work is supported by Russian Foundation for Basic Research (grant No. 19-08-00772). The study was conducted at the Joint Access Center “Mechanics” of ITAM SB RAS

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Usynina Yu. I., Yermolaev Yu. G., Kosinov A. D., Semionov N. V. Research on the Influence of the Unit Reynold’s Number on the Characteristics of N-Waves at M = 2.5 //Siberian Journal of Physics, 2021, vol. 16, no. 1, p. 53–64. (in Russ.) DOI 10.25205/2541-9447-2021-16-1-53-64

This paper presents the results of studying the features of the development of weak shock waves generated by a twodimensional roughness on the wall of the working part of a supersonic wind tunnel in a free flow at a Mach number of 2.5. The measurements were performed with a constant resistance thermoanemometer. It is shown that a twodimensional sticker induces weak shock waves into the free flow. They cause distortion of the average flow, the shape of which corresponds to the N-wave. High-intensity pulsations were recorded in the region of passage of a pair of weak shock waves. With an increase in the unit Reynolds number, the level of distortions of the average flow remains practically constant, but an increase in nonstationary disturbances is observed. It was found that the greatest increase in pulsations caused by Mach waves is observed in the area of the maximum gradient of the average flow. It is found that an increase in the number ReLleads to an expansion of the frequency range of unstable disturbances generated by a pair of weak shock waves.

Keywords
experimental studies, supersonic flow, N-wave, unit Reynolds number, thermoanemometer

Funding
The work was carried out within the framework of the Program of Fundamental Scientific Research of the State Academies of Sciences for 2013-2020 (project ÀÀÀÀ-À17-117030610125-7). The authors are grateful to the Center for collective use “Mechanics” for the provided equipment

 

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Sadovsky I. A., Katasonov M. M., Pavlenko A. M. Investigation of the Development of Local-ized Disturbances in the Boundary Layer of a Flat Plate under Conditions of Moderate Degree of the Incoming Flow Turbulence behind the Surface Step // Siberian Journal of Physics, 2021, vol. 16, no. 1, p. 65–80. (in Russ.) DOI 10.25205/2541-9447-2021-16-1-65-80

In a wind tunnel on a flat plate in a separated flow behind a rectangular step, the emergence and development of localized disturbances generated by low-frequency impulse deviations of the local surface section under conditions of low and moderate degrees of the incoming flow turbulence is studied. The results were obtained by hot-wire anemometry at low subsonic flow velocity. It was found that impulse deviations of the wall generate disturbances, which are socalled Streaky structures and wave packets of oscillations. The separation of the laminar boundary layer accelerates the growth of wave packets with subsequent turbulization of the near-wall flow. The specific features of the behavior of localized disturbances under conditions of moderate degree of free-stream turbulence are revealed.

Keywords
boundary layer, flow separation, transition to turbulence, streaky structures, wave packets, moderate free-stream turbulence level

Funding
This work was partially carried out within the framework of the Program of Basic Scientific Research of State Academies of Sciences for 2013–2020 (project AAAA-A17-117030610128-8) and with state support for scientific research conducted under the guidance of leading scientists in Russian universities, agreement No. 075-15-2019-1923

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Yatskikh A. A., Panina A. V., Kocharin V. L., Yermolaev Yu. G., Kosinov A. D., Semeniov N. V. Experimental Studies of the Impact of Periodic Modulation of the Flow on the De-velopment of Disturbances in the Boundary Layer of a Swept Wing at a M = 2.5 // Siberian Journal of Physics, 2021, vol. 16, no. 1, p. 81–90. (in Russ.) DOI 10.25205/ 2541-9447-2021-16-1-81-90

The results of experimental studies on the impact of periodic flow modulation on the development of natural disturbances and artificial localized wave packets in the boundary layer of a swept wing with a leading edge swept angle of 40 degrees at a Mach number M = 2.5 are presented. The boundary layer was modulated using periodic roughness on the model surface. Artificial wave packets were generated by a pulsed glow discharge. Hot-wire anemometer measurements showed that, according to the experimental conditions, periodic modulation of the boundary layer leads to the stabilization of the development of controlled localized disturbances and to an increase in the growth of natural disturbances.

Keywords
experiment, supersonic flow, hot-wire anemometer, laminar-turbulent transition, turbulence, boundary layer, swept wing

Funding
The research was carried out within the framework of the Program of Fundamental Scientific Research of the state academies of sciences in 2013-2020 (project No. AAAA-A17-117030610125-7) and was supported by the Grant of the President of the Russian Federation (MK-2491.2019.1). The study was conducted at the Joint Access Center “Me-chanics” of ITAM SB RAS

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Solid-State and Semiconductor Physics, Physics of Nanostructures

 

Azarov I. A., Kuper K. E., Lemzyakov A. G., Porosev V. V., Shklyaev A. A. The Modification of Optical Properties of the Surfaces by the Glancing Angle Deposition Technique // Siberian Journal of Physics, 2021, vol. 16, no. 1, p. 91–100. (in Russ.) DOI 10.25205/2541-9447-2021-16-1-91-100

The paper considers the optical properties and structure of thin films of titanium dioxide formed by the glancing angle deposition method. It was show that this method allows the formation of coatings having a significantly lower refractive index than that of the initial material. Thus, the experimentally obtained value of the refractive index of thin films of titanium dioxide was ~1.2, which is almost two times less than that of a polycrystalline material. This allows you to use this method to produce the coatings with a variable refractive index using only one material, changing the geometry of the deposition process only.

Keywords
glancing angle deposition, titanium dioxide, optical properties, ellipsometry

Funding
The reported study was funded by RFBR and Novosibirsk region according to the research project 19-42-540009 r_a. The work was done at the shared research center SSTRC on the basis of the VEPP-4 – VEPP-2000 Complex at BINP SB RAS, using equipment supported by project RFMEFI62119X0022. The SEM and ellipsometry studies were per-formed on the equipment of CKP “VTAN” in the ATRC department of NSU

 

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Gilev S. D., Prokopiev V. S. Electrical Resistivity of Aluminum under Shock Compression // Siberian Journal of Physics, 2021, vol. 16, no. 1, p. 101–108. (in Russ.) DOI 10.25205/2541-9447-2021-16-1-101-108

Electrical resistance measurements of aluminum foil are conducted under shock compression using the electric contact technique. Shock wave pressure p dependences of the electrical resistance R and the resistivity r are obtained for pressure range up to 22 GPa. The found dependence R(p) is a monotonically increasing smooth function of the pressure. The dependence r(p) is more complex: with increasing pressure, the electrical resistivity first decreases and then increases.

Keywords
electrical resistance, resistivity, aluminum, shock compression, high pressure and temperatures

 

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Izmailova G. R. Simulation of Electromagnetic-Acoustic Heating of the Oil Layer in Laboratory Conditions // Siberian Journal of Physics, 2021, vol. 16, no. 1, p. 109–116. (in Russ.) DOI 10.25205/2541-9447-2021-16-1-109-116

This paper describes an experiment to study the combined effects of high-frequency electromagnetic and acoustic fields on a model of an oil reservoir. A mathematical model is described that describes the physical processes that occur in the reservoir. The heat equation takes into account heat transfer with the environment by introducing an additional term. The largest discrepancy between theoretical and experimental data does not exceed 28%. Qualitative coincidence of theoretical and experimental curves indicates the adequacy of the mathematical model.

Keywords
high-frequency electromagnetic field, heat sources, thermoacoustic effect, thermal conductivity, reservoir model, temperature field

 

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Instructions to Contributors

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