Персона: Степаненко, Александр Александрович
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Институт лазерных и плазменных технологий
Стратегическая цель Института ЛаПлаз – стать ведущей научной школой и ядром развития инноваций по лазерным, плазменным, радиационным и ускорительным технологиям, с уникальными образовательными программами, востребованными на российском и мировом рынке образовательных услуг.
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- ПубликацияОткрытый доступAssessment of laser induced breakdown spectroscopy accuracy for determination of hydrogen accumulation in tungsten(2021) Tsygvintsev, I. P.; Marenkov, E. D.; Gasparyan, Y. M.; Stepanenko, A. A.; Маренков, Евгений Дмитриевич; Гаспарян, Юрий Микаэлович; Степаненко, Александр Александрович© 2021 The Author(s)Laser-induced breakdown spectroscopy (LIBS) is an in situ method of determining hydrogen (H) content in plasma-facing materials in tokamak fusion reactors. Observing radiation from the plasma plume produced by a powerful laser pulse during the target exposition characterizes the sample composition. This is typically accomplished using the Saha-Boltzmann (SB) plot technique under local thermodynamic equilibrium (LTE) conditions. Despite many experimental studies dedicated to applying LIBS to determine H isotope retention in fusion reactor materials, the current understanding of this method's intrinsic accuracy remains inadequate. In this report, we use numerical calculations to estimate the relative error of determining H content in a sample using LIBS. As an example. we consider LIBS to study a W sample loaded with H in a vacuum. Under typical LIBS pulse parameters (109 W/cm2 and 12 ns duration), the error can be quite large, approximately 70%. We demonstrate that the error tends to decrease as the laser pulse intensity increases. Various factors contributing to the relative error are examined and their dependence on the LIBS plasma parameters is discussed. The SB plot remains a straight line even when LTE conditions are violated, making it difficult to anticipate the experimental results’ error.
- ПубликацияОткрытый доступДИФФУЗИЯ ВОДОРОДА В ВОЛЬФРАМЕ В ПОЛЕ ДЕФЕКТОВ ПРИ НАЛИЧИИ ГРАДИЕНТА ТЕМПЕРАТУРЫ(НИЯУ МИФИ, 2018) СТЕПАНЕНКО, А. А.; ОРЕШНИКОВА, Н. М.; ПИСАРЕВ, А. А.; Писарев, Александр Александрович; Степаненко, Александр АлександровичКорректное предсказание количества трития, накопленного в тайлах токамака за время его работы, является одним из принципиальных вопросов, успешное решение которых необходимо для реализации проекта термоядерного реактора ИТЭР. По этой причине исследование динамики водорода в пластинах, выстилающих вакуумную камеру установки, представляет значительный интерес.
- ПубликацияТолько метаданныеCalorimetric and Spectroscopic Studies of Crystallization of Materials(2022) Klemazov, K. V.; Isaev, E. I.; Stepanenko, A. A.; Stepanov, V. A.; Исаев, Евгений Игоревич; Степаненко, Александр Александрович; Степанов, Владимир Александрович© 2022, Pleiades Publishing, Ltd.Abstract: The results of experimental determination of fluorozirconate glass crystallization temperatures by the methods of DSC and spectroscopy have been compared. It has been shown that the crystallization starting temperature, determined by an increase in the light scattering intensity, is 40° below the crystallization point, as seen by DSC. The effect of laser irradiation on the crystallization temperatures of glasses has been detected.
- ПубликацияТолько метаданныеImpact of electromagnetic effects on macroscopic dynamics of blobs in hot low-beta edge plasma of fusion devices(2020) Stepanenko, A. A.; Степаненко, Александр АлександровичThe impact of electromagnetic effects on macroscopic dynamics of blobs in hot low-beta ( beta < m e / m i) edge plasma of fusion devices is analyzed. The physical model governing filament dynamics is presented. The qualitative analysis of the blob motion in electrostatic and electromagnetic regimes is performed. The scalings for the plasma potential and filament advection velocity are obtained along with the estimates of plasma parameters, for which the physics of Alfven waves and skin effect can have an impact on the filament motion. It is shown that required edge/scrape-off layer conditions can be found in modern tokamaks. Analytical expressions for the distributions of the parallel current and electrostatic potential in a blob, containing electrostatic and electromagnetic contributions, are derived. It is demonstrated that in sufficiently hot, weakly resistive plasma the electromagnetic effects can lead to noticeable variations of the potential along the magnetic field lines distorting the blob propagation pattern in contrast to the electrostatic case. Results of the theoretical analysis are compared with results of 3D BOUT++ modeling, which show that in the electromagnetic limit, the macroscopic motion of blobs can exhibit ballooning features due to the emission of Alfven waves, absent in electrostatic simulations. It is concluded that, at least in the near scrape-off layer region of fusion devices, electromagnetic models of plasma dynamics may be appropriate for the analysis of blob motion instead of electrostatic ones.
- ПубликацияТолько метаданныеFeatures of Vortex Dynamics in a HTS with Disordered Pinning Lattice(2024) Moroz, A.; Rudnev, I.; Stepanenko, A.; Maksimova, A.; Kashurnikov, V.; Мороз, Анна Николаевна; Руднев, Игорь Анатольевич; Степаненко, Александр Александрович; Максимова, Анастасия Николаевна; Кашурников, Владимир Анатольевич
- ПубликацияОткрытый доступImplementation of SOLPS-ITER code with new Grad-Zhdanov module for D-T mixture(2023) Makarov, S. O.; Coster, D. P.; Kaveeva, E. G.; Stepanenko, A. A.; Степаненко, Александр Александрович
- ПубликацияТолько метаданныеEffects of magnetic geometry on dynamics of current-convective turbulence in tokamak divertor plasma(2022) Stepanenko, A. A.; Степаненко, Александр Александрович
- ПубликацияТолько метаданныеImpact of Generalized Sheath Boundary Conditions on Dynamics of Plasma Filaments at the Tokamak Edge(2022) Stepanenko, A. A.; Степаненко, Александр АлександровичAbstract: The impact of generalized sheath boundary conditions, taking into account the sheath perturbations driven by the Alfvén waves, on the propagation of plasma filaments at the tokamak edge is considered. A model describing the filament dynamics and containing new boundary conditions is developed. Estimates of the model control parameter—the sheath impedance—on the plasma transport are obtained. Simulations of the filament dynamics under the conditions characteristic of edge plasmas in NSTX and Alcator C‑Mod tokamaks are performed. It is shown that the sheath impedance leads to an increase in the mean values of the electrostatic potential and advection velocities of filaments, in agreement with experimental observations, requiring, at the same time, a more detailed description of the Alfvén wave reflection from the conducting surfaces of the installations. © 2022, Pleiades Publishing, Ltd.
- ПубликацияТолько метаданныеBoundary slip phenomena in multicomponent gas mixtures(2019) Zaznoba, V. A.; Stepanenko, A. A.; Zhdanov, V. M.; Степаненко, Александр Александрович© 2019 Author(s).The slip phenomena in multicomponent gas mixtures are studied. The moment equations, derived from the linearized Boltzmann equation by using the 13-moment approximation of the Grad's method, are used to obtain the full (containing the contribution from the Knudsen layer) and asymptotic (valid far from the plane physical boundary of the domain) expressions for the nonequilibrium macroscopic parameters of the mixture species. The latter relations are employed to deduce the expressions for the mixture slip velocity and the viscous, thermal, and diffusion slip coefficients by using the modified Maxwell method and the diffuse-specular model of molecule scattering on the wall. The derived relations for the slip coefficients are given in the convenient form expressed in terms of basic transport coefficients, such as partial viscosity and thermal conductivity coefficients, diffusion and thermal diffusion coefficients, and coefficients of molecule momentum accommodation at the wall. The expressions found are used to calculate the slip coefficients for binary (He-Ar) and ternary (He-Ar-Xe) gas mixtures. The numerical results are in good agreement with the data calculated by using other methods.
- ПубликацияТолько метаданныеPossibility of using machine learning methods to reconstruct solid body parameters during laser-induced desorption analysis(2023) Stepanenko, A. A.; Kashin, D. A.; Gasparyan, Y. M.; Степаненко, Александр Александрович; Гаспарян, Юрий Микаэлович