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Issue 3, 2025

Physics of nuclei and elementary particles

Radiation technologies for the treatment of biological objects

Radiation technologies for the treatment of biological objects

A. P. Chernyaev$^{1,2}$, V. V. Rozanov$^{1,3}$, E. K. Kozlova$^{1,4}$, I. V. Matveychuk$^3$, U. A. Bliznyuk$^{1,2}$, V. S. Ipatova$^2$

Moscow University Physics Bulletin 2025. N 3.

The article provides an overview of the current state of application of radiation technology in food processing and biomedical products in the world and in Russia. The history of the development of radiation technology and its connection with the development of radiation engineering facilities used for processing biological objects and materials is described. The characteristics of radiation sources and doses used in the processing of food and biomedical products are presented. The main international and national standards governing radiation processing of food products and medical devices, dose control and methods of identification of irradiated food products are presented. The article studies the physical mechanisms of radiation effects on target microorganisms and surrounding biological macromolecules in irradiated biological objects. The main Russian research centers conducting research in the field of radiation treatment of biological objects and materials are given, and industrial centers providing radiation treatment services in the Russian Federation are presented. The article provides an overview of the main directions and results of research on optimization of radiation processing of biological objects and materials carried out at the Department of Accelerator Physics and Radiological Medicine, Faculty of Physics, Moscow State University over the past 15–20 years.

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Physics of nuclei and elementary particles

Human internal radiation doses from radon during heating of dwelling houses with natural gas in northern conditions

Human internal radiation doses from radon during heating of dwelling houses with natural gas in northern conditions

K. V. Nikolaevich, P. K. Alekseevna, P. A. Vladimirovna, M. S. Nikolaevna

Moscow University Physics Bulletin 2025. N 3.

In some sources there is information that natural gas may contain radon, but there are no detailed studies of radon emanation from network natural gas, and also this problem of radon emanation from natural gas has an important practical significance in connection with the implementation of the program of gasification of settlements in Yakutia. It is known that radon is one of the main causes of cancer development, including more often lung cancer. Studies conducted in different countries have shown that even low concentrations of radon registered in residential premises create health risks and contribute to the development of lung cancer. It is known that prolonged exposure to radon with an average concentration increased by 100 Bq/m3 increases the probability of developing lung cancer by 16%. On this basis, the study of radon safety in permafrost conditions is an urgent problem.

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Issues of Improving the Efficiency and Resolution of the Neutron Spectrometer for the National Center for Physics and Mathematics

Issues of Improving the Efficiency and Resolution of the Neutron Spectrometer for the National Center for Physics and Mathematics

A. M. Lapik$^1$, S. S. Belyshev$^2$, V. V. Varlamov$^3$, L. Z. Dzhilavyan$^1$, A. A. Kuznetsov$^{2,3}$, A. L. Polonski$^1$, A. V. Rusakov$^1$, V. I. Shvedunov$^3$

Moscow University Physics Bulletin 2025. N 3.

For γ-quantum energies in the E1 GR region, the following is analyzed: requirements for (γ, n)-experiments with fast neutron spectrometry; parameters of collimated Compton radiation sources HIγS and NCPhM; characteristics of the neutron spectrometer proposed for NCPhM; principles of one-dimensional time-coordinate compensation for neutron spectrometer scintillators. Initial experiments have been conducted to study the possibilities of improving the efficiency and resolution of such a neutron spectrometer using the time-coordinate compensation method

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THE CONDITIONS FOR THE FORMATION OF 17 SUPERCONDUCTING PAIR CORRELATIONS IN SPHERICAL EVEN-EVEN NUCLEI

THE CONDITIONS FOR THE FORMATION OF 17 SUPERCONDUCTING PAIR CORRELATIONS IN SPHERICAL EVEN-EVEN NUCLEI

V. A. Kuz'min$^1$, T. V. Tetereva$^2$

Moscow University Physics Bulletin 2025. N 3.

The formation of superconducting pair correlations between like nucleons in the ground state of spherical even-even nuclei is considered within a special Bogoli ubov transformation. The inuence of the monopole pairing interaction on the energy of single-particle states is taken into account. It is shown that the appear ance of pair correlations depends on the particle number and shell structure. In open subshell nuclei the correlations exist at any attractive monopole interaction and nucleon pairs are distributed over all subshells participating in the pairing interaction. It is con rmed that the superconducting pair correlations appear if the coupling constant exceeds a certain threshold value. Rough upper and lower estimates are obtained for the threshold value

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Misalignment alignment influence on MPD TPC track reconstruction

Misalignment alignment influence on MPD TPC track reconstruction

V. A. Kuzmin

Moscow University Physics Bulletin 2025. N 3.

Using the previously developed method for finding the alignment of the Time Projection Camera (TPC) in the MPD detector, we study the effect of misalignment on the reconstructed parameters of a charged particle track, such as transverse momentum and velocity. The concept of a misalignment unit is introduced for TPC. By simulating the reaction of the TPC to charged particles, we study the distortions that are introduced into the reconstructed track parameters depending on the magnitude of the misalign- ment. The effect of misalignment on the reconstructed track parameters in the MPD TPC is negligible. There is a systematic shift in the measured transverse momentum, depending on the track projection width. This width is determined by the gas and electrical field conditions within the detector chamber. Alignment tools developed for the MPD Time Projection Chamber allow us to estimate this width using experimental data and apply corrections to the reconstructed track parameters.

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Heavy-ion Physics Results by the Compact Muon Solenoid (CMS) Expe\-riment at the Large Hadron Collider (LHC)

Heavy-ion Physics Results by the Compact Muon Solenoid (CMS) Expe\-riment at the Large Hadron Collider (LHC)

S. V. Petrushanko

Moscow University Physics Bulletin 2025. N 3.

This publication presents the latest experimental results on the physics of relativistic heavy ion collisions obtained at the Compact Muon Solenoid (CMS) facility at the Large Hadron Collider (LHC) at CERN.

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Radial dependence of the nucleon effective mass and the ground-state properties of magic nuclei

Radial dependence of the nucleon effective mass and the ground-state properties of magic nuclei

D. Yu. Smoliannikov$^1$, N. N. Arsenyev$^1$, A. P. Severyukhin$^{1,2}$

Moscow University Physics Bulletin 2025. N 3.

The contributions of various terms to the nucleon effective mass are analyzed using the self-consistent Hartree-Fock method based on Skyrme-type energy density functional (EDF). The terms of the EDF that impacts nucleon effective mass at the surface of a nucleus has been included. The effects of these terms on the ground-state properties (nuclear charge radii, binding energy and single-particle spectra) of doubly closed shell nuclei $^{16}$O, $^{40,48}$Ca, $^{56,78}$Ni, $^{100,132}$Sn and $^{208}$Pb are examined. It has been found that the radial dependence of nucleons' effective mass influences both the density diffuseness and the scheme of single-particle levels near the Fermi level. Two new sets of parameters for the nuclear density functional have been proposed.

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Condensed matter physics

The Influence of Thermal Annealing Regimes on the Magnetic Permeability of (Co Fe)75Si10B15 Based Amorphous Ribbons

The Influence of Thermal Annealing Regimes on the Magnetic Permeability of (Co Fe)75Si10B15 Based Amorphous Ribbons

A. A. Isayeva, V. I. Ahmadov, F. S. Mammadov, G. Z. Askerova, S. M. Musayeva

Moscow University Physics Bulletin 2025. N 3.

Данное исследование посвящено влиянию режимов термического отжига на магнитную проницаемость аморфных ленточных образцов (Co Fe)75Si10B15. Благодаря своей уникальной структуре аморфные материалы отличаются высокими магнитными свойствами, на которые могут существенно влиять процессы термического отжига. В данной работе исследовалась зависимость максимальной магнитной проницаемости от времени изотермической выдержки и температуры при термическом отжиге на воздухе при 200°C-400°C, а также изучались процессы диффузии. Основная цель — понять, как изменяется максимальная магнитная проницаемость аморфных ленточных образцов (CoFe)75Si10B15 при различных температурах и временах изотермической выдержки. Результаты показывают, что отжиг при температурах 300-400°C значительно улучшает магнитную проницаемость лент, тем самым расширяя их потенциальные области применения. Данное исследование определяет, как магнитные свойства аморфных лент могут быть улучшены посредством термического отжига. В этом исследовании подчеркивается важность оптимизации термического отжига для дальнейшего развития областей применения аморфной ленты.

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Dynamics of paramagnetic centers in hafnium oxide during electron beam deposition

Dynamics of paramagnetic centers in hafnium oxide during electron beam deposition

E. A. Konstantinova, A. V. Koroleva, A. V. Pavlikov, E. V. Kytina, A. S. Ilin, M. N. Martyshov

Moscow University Physics Bulletin 2025. N 3.

Hafnium oxide, which has a high permittivity, is of interest for use as memristors in electronics. In this paper, a comparative analysis of the type and main characteristics of paramagnetic centers in a series of samples that underwent successive synthesis stages: from the initial target sample to the film on the substrate is performed for the first time. It is found that the main type of defects in the studied materials are oxygen vacancies with an unpaired electron (F+ centers). It is found that during the sputtering of the target (crystalline hafnium oxide), the concentration of F+ centers decreases, probably, during the recharging process. It is found that in the sputtered hafnium oxide film, the concentration of F+ defects increases by an order of magnitude. The discovered experimental fact is explained by the disordered (amorphous) structure of the film. The obtained results are of great importance from both fundamental and practical points of view, since F+ are charge carrier trapping centers and, therefore, have a significant impact on the electronic characteristics of hafnium oxide, which determine its use in electronic devices.

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Контролируемый рост углеродных нанотрубок и высокоупорядоченного графена на поверхности Pt(111) с использованием молекул фторфуллерена

Контролируемый рост углеродных нанотрубок и высокоупорядоченного графена на поверхности Pt(111) с использованием молекул фторфуллерена

D. A. Muzychenko$^1$, S. I. Oreshkin$^2$, V. O. Surov$^1$, A. V. Samorodskiy$^1$, М. Yu. Alexandrov$^1$, V. I. Panov$^1$, А. И. Орешкин$^1$

Moscow University Physics Bulletin 2025. N 3.

Продемонстрирована возможность использования фторфуллерена C60F48 для осуществления контролируемого роста углеродных нанотрубок и доменов высокоупорядоченного графена, стимулированного промежуточным фоторированием поверхности платинового катализатора. Для обеспечения легкого отщепления атомов фтора от углеродного каркаса на поверхности Pt(111) была выбрана молекула C60F48. Показано, что молекулы фторфуллерена распадаются на поверхности Pt(111), теряя атомы фтора уже при комнатной температуре. Высокотемпературный пиролиз способствует фторированию поверхности Pt(111) и связыванию аморфного углерода, вызывая последовательный рост углеродных нанотрубок и графена при повышении температуры.

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Features of pinning mechanism determination in samples of the family of iron pnictides of the class 111

Features of pinning mechanism determination in samples of the family of iron pnictides of the class 111

E. M. Fomina, A. I. Shilov$^2$, E. O. Rahmanov$^{2,3}$, I. V. Zhuvagin$^2$

Moscow University Physics Bulletin 2025. N 3.

The paper analyzed the applicability of the values of the strength 𝐻𝑖𝑟𝑟 of the irreversibility field and the strength 𝐻𝑐2 of the upper critical field in determining the pinning mechanism in a sample of the class 111 family of iron pnictides (𝑁𝑎𝐹𝑒(1−𝑥)𝐶𝑜(𝑥)𝐴𝑠). The methods of calculating 𝐻𝑖𝑟𝑟 and 𝐻𝑐2 were also considered. The first method for determining the values of the intensity 𝐻𝑖𝑟𝑟 of the irreversibility field is based on extrapolation of the zeros of the graph 𝐽𝑐(𝐻). The second method, considered exclusively from a theoretical point of view, is Kramer’s method. It is based on the extrapolation of graph zeros 𝐽1/2 𝑐 * 𝐵1/4(𝐵). Each of the methods requires a qualitative determination of the zeros of the graphs in order to obtain the most accurate result. The strength of the upper critical field is determined by extrapolating the points obtained at the intersection of the graph M(T) with the straight line of the level M = 0. Due to the limited operating range of the measuring device the values 𝐻𝑖𝑟𝑟 for the sample 𝑁𝑎𝐹𝑒(1−𝑥)𝐶𝑜(𝑥)𝐴𝑠 were determined by approximating data from previously obtained results. When using 𝐻𝑖𝑟𝑟, the volume pinning type was determined. The values of 𝐻𝑐2 were also calculated based on the data already obtained and allowed us to determine the surface pinning mechanism. The result is consistent with earlier studies. This means that the pinning mechanism, which was determined using the values 𝐻𝑖𝑟𝑟, is installed incorrectly. It was found that the application of the values of the field strength of irreversibility may lead to incorrect pinning type determination for the sample 𝑁𝑎𝐹𝑒(1−𝑥)𝐶𝑜(𝑥)𝐴𝑠.

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Theoretical and mathematical physics

Remote fiber 3D-microprobing of scattering media

Remote fiber 3D-microprobing of scattering media

D. A. Balakin, A. V. Belinsky

Moscow University Physics Bulletin 2025. N 3.

A new method of microprobing scattering media for studying their three-dimensional structure using femtosecond pulses propagated to the object and back using a bundle of single-mode fibers is considered. In this case, the second harmonic is formed by summing the frequencies of the backscattered and reference signals and it is subsequently detected. Using computer modeling, a number of algorithms for reconstructing the spatial distribution of the attenuation coefficient and their combination are studied.

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Secure Quantum Channels Based on Multiphoton Entanglement

Secure Quantum Channels Based on Multiphoton Entanglement

A. V. Belinsky, A. P. Grigorieva, I. I. Dzhadan

Moscow University Physics Bulletin 2025. N 3.

The possibilities of information transmission by quantum channels with multiphoton. Protocols for quantum key distribution and direct information transmission with strict consideration of the time of sending and receiving messages are compiled, which helps to counteract a wide range of attacks.

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Dual symmetry of effective dense QCD models

Dual symmetry of effective dense QCD models

R. N. Zhokhov$^1$, T. G. Khunjua$^2$, K. G. Klimenko$^3$

Moscow University Physics Bulletin 2025. N 3.

In this paper, we study the symmetry properties of the phase diagram of dense quark matter consisting of $u$ and $d$ three-color quarks within the framework of massless (3+1)-dimensional Nambu-Jona-Lasinio models and quantum chromodynamics. It turns out that in the presence of baryon $\mu_B$, isospin $\mu_I$, chiral $\mu_5$ and chiral isospin $\mu_{I5}$ chemical potentials, the Lagrangians of these models are invariant under the so-called dual transformation. Consequently, the total thermodynamic potentials of these models are dually symmetric. This means that in the full $(\mu_B,\mu_I,\mu_5,\mu_{I5})$-phase portraits of these models, the phases with spontaneous breaking of chiral symmetry and condensation of charged pions are dually conjugate (symmetric) to each other.

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Existence and stability of stationary boundary layer solution in a two-dimensional system of fast and slow reaction-diffusion-advection equations with KPZ-nonlinearities

Existence and stability of stationary boundary layer solution in a two-dimensional system of fast and slow reaction-diffusion-advection equations with KPZ-nonlinearities

A. O. Orlov

Moscow University Physics Bulletin 2025. N 3.

The paper considers a boundary value problem for a singularly perturbed elliptic system of fast and slow equations, which is commonly called a Tikhonov-type system. The problem in question features terms containing the squared gradient of the unknown function (KPZ- nonlinearities). The boundary-layer asymptotics of the solution in the case of the Dirichlet boundary condition is constructed, the existence of a solution with the constructed asymptotics is proved, and its Lyapunov stability is investigated. The proof of the theorem was carried out using asymptotic method of differential inequalities by N. N. Nefedov.

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Estimation of possible supersaturation of solutions at ion exchange in porous media.

Estimation of possible supersaturation of solutions at ion exchange in porous media.

N. A. Tikhonov

Moscow University Physics Bulletin 2025. N 3.

The phenomenon of isothermal supersaturation of solutions in a porous medium at ion exchange is studied on the basis of mathematical modeling. The phenomenon consists in the fact that the solution with concentration significantly higher than the maximal solubility of the substance is formed in the pores of sorbent and no precipitation occurs. The general nature of the phenomenon has been noted in the works of some authors and an explanation was given for the stability of the supersaturated solution in the micropores of ion exchangers. The question of why sediment does not appear in larger pores remains open. In this paper, a model of changing of the number of condensed phase particles in pores is proposed and estimates are obtained that allow one to determine the degree of possible supersaturation depending on the process parameters. It is shown that the phenomenon under consideration can be explained not by a change in thermodynamic conditions in a porous medium, compared to normal conditions, but by the effect of dynamic equilibrium between the association of condensed phase particles in the inner part of the pores, their diffusion and their decomposition near the surface of the ion exchanger grains. The proposed hypothesis is confirmed by quantitative studies and comparison with available experimental data.

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Analytical models of the nonstationary planet’s physical fields in the local version

Analytical models of the nonstationary planet’s physical fields in the local version

A. G. Yagola$^1$, I. E. Stepanova$^2$, A. N. Levashov$^1$, I. I. Kolotov$^1$, A. V. Gorbachev$^1$

Moscow University Physics Bulletin 2025. N 3.

The local versions of the linear integral representation method proposed is implemented for mathematical modeling of anomalous time-dependent field data. Variational settings of coefficient inverse problems for two nonlinear differential equation systems appearing in the magnetic hydrodynamics are described. Uniqueness theorem for the solution of the inverse coefficient problem relating to the charged magnetic liquid is formulated.

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Optics and spectroscopy. Laser physics

Light coupling devices for subwavelength waveguides based on second order surfaces manufactured by two-photon laser lithography

Light coupling devices for subwavelength waveguides based on second order surfaces manufactured by two-photon laser lithography

I. O. Batuev$^1$, K. A. Smirnov$^1$, I. I. Tsiniaikin$^2$, A. I. Maydykovskiy$^1$, T. V. Murzina$^1$

Moscow University Physics Bulletin 2025. N 3.

Light input/output devices are essential for coupling between bulk and fiber optical devices and photonic integrated circuits (PIC). In this work, broadband couplers for optical waveguides lifted from the surface, were fabricated by two-photon laser lithography, and comparison with numerical modeling was conducted. It was demonstrated experimentally that the ellipsoid-based coupler is optimal for coupling light with the waveguide. Average transmittance of a system of two adapters in the spectral range 700-1000 nm for s-polarized radiation amounted to at least 27%.

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erturbation theory of the surface in the problem of elastic light scattering by microparticles

erturbation theory of the surface in the problem of elastic light scattering by microparticles

A. B. Remzievich$^{1,2}$, A. F. Uspenksiy$^{1,2}$, A. A. Fedyanin$^2$, B. S. Lukyanchuk$^2$

Moscow University Physics Bulletin 2025. N 3.

The problem of light scattering by particles of arbitrary axisymmetric shape has been solved using the perturbation theory method. The proposed approach enables the analysis of significant deformations by dividing the overall deformation into smaller ones. Convergence, limitations, and conditions of applicability are discussed, and a comparison with an alternative calculation method is provided.

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An analytical method for estimating the effect of small losses in layers of periodic two-component antireflection structures with coupled wave thicknesses of layers in a period on their optical characteristics

An analytical method for estimating the effect of small losses in layers of periodic two-component antireflection structures with coupled wave thicknesses of layers in a period on their optical characteristics

A. E. Zhitelev, A. V. Kozar

Moscow University Physics Bulletin 2025. N 3.

The paper proposes a method for estimating the effect of low losses in layers of periodic two-component antireflection structures on their optical characteristics using simple analytical ratios. The efficiency of the proposed method is shown for various refractive indices of the illuminated media, absorption coefficients of the materials of the layers of the structure and the number of layers. The correctness of the obtained results is confirmed by numerical experiment.

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Anharmonic quantum oscillator as a model of resonant optics

Anharmonic quantum oscillator as a model of resonant optics

A. M. Basharov

Moscow University Physics Bulletin 2025. N 3.

The peculiarities of the theory of resonant interactions of electromagnetic coherent fields with an anharmonic oscillator in comparison with the case of a multilevel atom are emphasized. It is shown that within the framework of the local approach, algebraic resonance perturbation theory, it is possible to take into account the requirements of the global approach of the theory of open quantum systems. Based on an auxiliary model of the "internal nonlinearity" of an anharmonic oscillator, the possible conditions of resonance of a coherent wave with an anharmonic oscillator with the absorption of a single photon are analyzed.

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Схема квантовых коммуникаций, описываемая регулярным четырехмерным комплексным политопом

Схема квантовых коммуникаций, описываемая регулярным четырехмерным комплексным политопом

А. Ю. Власов$^{1,2}$

Moscow University Physics Bulletin 2025. N 3.

В настоящее время обобщения протоколов квантовых коммуникаций с кубитов на системы с более высокой размерностью пространства состояний (кудиты) обычно используют взаимно несмещённые базисы, конструкция которых известна в любой размерности равной степени простого числа. Однако, в небольших размерностях также существуют формально более симметричные системы состояний, описываемые регулярными комплексными политопами, являющимися обобщением идеи правильных многогранников на комплексные пространства. В данной работе рассматривается применение модели, изначально предложенной Р. Пенроузом и построенной на основе геометрии додекаэдра и двух квантово запутанных частиц со спином 3/2. В более общем случае вместо них можно использовать две произвольные квантовые системы с четырьмя базисными состояниями (кукварты). В дальнейшем было показано, что эта система из 40 состояний эквивалентна конфигурации Виттинга и связанна с четырехмерным комплексным политопом описанным Кокстером. В работе предложен использующий данную конфигурацию протокол квантового распределения ключей, основанный на контекстуальности.

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Quantum algorithms parallelization with quantum teleportation

Quantum algorithms parallelization with quantum teleportation

S. S. Sysoev

Moscow University Physics Bulletin 2025. N 3.

In this work, a method for parallelizing quantum algorithms in the circuit model is proposed, based on the technique of quantum gate teleportation. The parallel representation of the algorithm obtained in this way has a reduced circuit depth and, consequently, a higher probability of correct execution under conditions of quantum state decoherence that increases over time. The reduction of the circuit length is achieved by increasing its width—the number of qubits used simultaneously in computations.

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Quantum oscillator as a open system

Quantum oscillator as a open system

A. I. Trubilko

Moscow University Physics Bulletin 2025. N 3.

The possibility of using the quantum oscillator model in the theory of open quantum systems is demonstrated by means of algebraic perturbation theory. The case of resonant and non-resonant interactions of two spatially separated oscillators is considered, each of which interacts with its own thermostat at different temperatures. The possibility of decay of an isolated oscillator during its non-resonant interaction into an oscillator-mediator in the environment of the latter is demonstrated. In all the cases presented, algebraic perturbation theory does not lead to any non-physical features or contradictions such as violation of the second law of thermodynamics and discrepancies in the description of these cases within the framework of the global and local approaches

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Biophysics and medical physics

The investigation of topography and mechanical properties of the living cell-hydrogel system by scanning ion-conduction microscopy

The investigation of topography and mechanical properties of the living cell-hydrogel system by scanning ion-conduction microscopy

T. N. Tikhonova$^1$, A. V. Barkovaya$^2$, V. V. Mamed-Nabizade$^3$, V. S. Kolmogorov$^3$, S. T. Matskeplishvili$^4$, N. N. Sysoev$^5$, A. S. Erofeev$^3$, V. V. Fadeev$^5$

Moscow University Physics Bulletin 2025. N 3.

Hydrogels are currently gaining interest due to their unique characteristics for use in various applications such as regenerative medicine, 3D cell culturing and drug delivery. The main challenge in the application of hydrogels in tissue engineering is the accurate assessment of their mechanical characteristics. In this work, a non-invasive scanning ion-conduction microscopy (SIPM) method is used to determine the stiffness of living human neuroblastoma SH-SY5Y cells grown on a soft, self-organizing hydrogel made of Fmoc-FF peptide. Young's modulus for SH-SY5Y cells decreases with increasing substrate stiffness, with values of 1015 Pa and 750 Pa on petri dish and Fmoc-FF hydrogel, respectively. This method enables simultaneous investigation of the stiffness of living cells and soft hydrogels, which is promising in the field of regenerative medicine.

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Astronomy, astrophysics, and cosmology

Analysis of Balmer series emission in the solar flare SOL2017-04-21

Analysis of Balmer series emission in the solar flare SOL2017-04-21

Yu. A. Kupryakov$^1$, V. A. Maliytin$^2$, K. V. Bychkov$^1$, A. B. Gorshkov$^1$, O. M. Belova$^3$

Moscow University Physics Bulletin 2025. N 3.

We observed B6.2 class solar flare in the NOAA 12651 active region on HSFA spectrograph of Ond\v{r}ejov observatory in hydrogen spectral lines. After processing the spectra, we determined integral radiation fluxes in the H$\alpha$, H$\beta$ and H$\varepsilon$ lines. Within the approach of heated gas model theoretical reconstruction of plasma parameters was performed taking into account the physical conditions in the chromosphere comprising self-absorption in spectral lines. Treating the observed fluxes leads to the consideration of inhomogeneous gas. Matching of theoretical fluxes with observed ones is achieved in the framework of two gas layers. Dense gas with concentration $N$ ranging from $3\,10^{12}\text{см}^{-3}$ to $3\,10^{13}\text{см}^{-3}$ is located behind the rarefied layer with $N=(3\div6)10^{10}\text{см}^{-3}$. Layer thickness varies from 600 to 3000 km, temperature ranges from 4000 to 7200 K, and turbulent velocity --- from 0 to 90 km/s. The presence of the dense region reveals the chromospheric origin of the gas.

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An algorithm for study transiting exoplanet candidates by the MASTER global robotic telescope net

An algorithm for study transiting exoplanet candidates by the MASTER global robotic telescope net

A. N. Tarasenkov$^{1,3}$, V. M. Lipunov$^{1,2}$, A. S. Kuznetsov$^1$, N. M. Budnev$^4$, A. G. Tlatov$^5$, V. V. Yurkov$^6$

Moscow University Physics Bulletin 2025. N 3.

The paper presents the basic principles of photometric research of exoplanet candidates through the analysis of archival wide-field images obtained on robotic telescopes of the MASTER global network of Moscow State University. An algorithm for studying candidates for transiting exoplanets was proposed and applied to study and search for candidates for transiting exoplanets. It which does not interfere with the performance of the main tasks of the MASTER network - detection of optical components of high-energy astrophysical sources and study of the processes occurring in them on various time scales. A number of candidates from the field of microquasar V404 Cyg were studied. For the candidate TOI-3570.01, a light curve was obtained during the transit of a putative exoplanet with a high photometric accuracy.

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Engineering physics

New Approaches to Visualization and Analysis of Flows in Shock Tubes

New Approaches to Visualization and Analysis of Flows in Shock Tubes

D. I. Dolbnia, I. A. Doroshchenko, I. A. Znamenskaya, M. I. Muratov

Moscow University Physics Bulletin 2025. N 3.

This paper presents new approaches to studying gas-dynamic processes in shock tubes using modern visualization and analysis methods. The flow behind the shock wave in a rectangular channel of a shock tube of constant cross-section and in a channel with an obstacle was studied. The experiments include the use of high-speed digital shooting, infrared thermography, and a tracing method, which allow analyzing the evolution of the flow in the shock tube with high temporal and spatial resolution. The results showed that the flow in the shock tube channel can be used for research for 20 – 25 milliseconds, which significantly exceeds the previously used time ranges. It is possible to conduct experiments, including studies of heat and mass transfer associated with flow around the walls of the channel, obstacles with the initiation of pulsed discharges in the flow. The results of a study of the evolution of flow parameters are presented. It is shown that the use of machine learning and computer vision methods, including convolutional neural networks, allows efficient processing and analysis of large arrays of data obtained during high-speed recording.

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