Персона: Кукушкин, Александр Борисович
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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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Александр Борисович
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- ПубликацияТолько метаданныеSuperdiffusive Transport Based on Levy Walks in a Homogeneous Medium: General and Approximate Self-Similar Solutions(2020) Kulichenko, A. A.; Kukushkin, A. B.; Кукушкин, Александр Борисович© 2020, Pleiades Publishing, Inc.Abstract: The general and approximate self-similar solutions for the Green’s function have been obtained for a wide class of integrodifferential equations for the two- and three-dimensional (in spatial coordinates) nonstationary superdiffusive transport of a perturbation of a homogeneous medium for a finite fixed velocity of carriers. This problem concerns the transport of resonance radiation in astrophysical gases and plasma, migration of animals, and the transfer of energy of electromagnetic waves in the plasma. The case of a model free path distribution function decreasing by a power law with increasing distance has been considered. Numerical calculations have been performed for two particular types of free path distribution functions, including the case with a Lorentzian shape of wings of the spectral line profile for the emission of photons by atoms or ions. The method developed in [A.B. Kukushkin and P.A. Sdvizhenskii, J. Phys. A: Math. Theor. 49, 255002 (2016)] for an infinite velocity of carriers has been used to construct the approximate self-similar solution. The inclusion of a finite velocity corresponds to the generalization of transport based on Lévy flights to transport based on “Lévy walks with stops.” The self-similar solution for arbitrary one-dimensional superdiffusive transport obtained in [A.B. Kukushkin and A.A. Kulichenko, Phys. Scripta 94, 115009 (2019)] has been applied to the case of the two- and three-dimensional transports. The accuracy of the self-similar solution has been tested by comparing it to the numerically calculated general solution.
- ПубликацияТолько метаданныеAnalysis of accuracy of measuring the flux density of all hydrogen isotopes from first wall to plasma using the H-alpha diagnostics in ITER АНАЛИЗ ТОЧНОСТИ ИЗМЕРЕНИЯ ПЛОТНОСТИ ПОТОКА ВСЕХ ИЗОТОПОВ ВОДОРОДА С ПЕРВОИ СТЕНКИ В ПЛАЗМУ С ПОМОЩЬЮ Н-АЛЬФА-ДИАГНОСТИКИ В ИТЭР(2019) Neverov, V. S.; Shurygin, V. A.; Alekseev, A. G.; Kukushkin, A. B.; Lisitsa, V. S.; Кукушкин, Александр Борисович; Лисица, Валерий Степанович© 2019 National Research Center Kurchatov Institute. All rights reserved.The results of the analysis of the accuracy of measuring the flux density of all hydrogen isotopes from the first wall of the main vacuum chamber to the ITER tokamak plasma using the high-resolution spectroscopy of Balmer-alpha lines of hydrogen isotopes (H-alpha diagnostics) are presented. Under the conditions of the expected high background radiation generated by the divertor stray light and the absence of the possibility of using the optical dumps in ITER, a differential measurement scheme is necessary, which uses the spatial variation of the coefficient of the light reflection from the natural landscape of the first wall. The measurement accuracy analysis is carried out with the help of the method of synthetic diagnostics, which uses the results of the predictive numerical modeling of different modes of hydrogen recycling for simulation of the expected diagnostic signals and determination of the sought-for parameters by solving an inverse problem.
- ПубликацияТолько метаданныеSpectral intensity of electron cyclotron radiation emerging from the plasma to the first wall in tokamak-reactors СПЕКТРАЛЬНАЯ ИНТЕНСИВНОСТЬ ЭЛЕКТРОННОГО ЦИКЛОТРОННОГО ИЗЛУЧЕНИЯ, ВЫХОДЯЩЕГО ИЗ ПЛАЗМЫ ТОКАМАКА-РЕАКТОРА НА ПЕРВУЮ СТЕНКУ(2019) Minashin, P. V.; Kukushkin, A. B.; Кукушкин, Александр Борисович© 2019 National Research Center Kurchatov Institute. All rights reserved.Electron cyclotron radiation (ECR) in tokamak-reactors, due to high electron temperature and high magnetic field, is expected to play a significant important role in the local electron energy balance and will also be a source of thermal and electromagnetic loads on the in-vessel components and diagnostics. This is especially important for diagnostics using millimeter waves, namely the reflectometry from the sides of the strong and weak magnetic field, reflectometry of the plasma position, as well as collective Thomson scattering, since the transmission lines of these diagnostics allow the transport of EC waves emerging from the plasma and even additional measurements of their spectrum. The paper presents an algorithm for calculating the spectral intensity of EC radiation emerging from the plasma to the first wall for typical conditions of a tokamak-reactor. To illustrate the algorithm, the calculations for typical scenarios of ITER and DEMO tokamaks are presented. The possible effect of this radiation on the in-vessel components and diagnostics of the tokamak-reactor is briefly discussed.
- ПубликацияТолько метаданныеModification of SXB Method for Hydrogen in ITER Main Chamber(2019) Khusnutdinov, R. I.; Kukushkin, A. B.; Хуснутдинов, Радмир Ильдарович; Кукушкин, Александр Борисович© 2019, Pleiades Publishing, Ltd.A modification of the SXB method, used for evaluating the atom/ion flux from the tokamak first wall into plasma using the observed wavelength-integrated spectral line intensity, is proposed. The modification allows, using the high-resolution spectroscopy data, to estimate — in real time measurements — the fluxes of atomic and molecular hydrogen from the first wall of the tokamak main chamber into plasma without measurements of molecular spectra. The modified SXB method is tested by comparing the results with the SOLPS code simulations for six modelled types of the SOL plasma profiles in ITER. The proposed modification is motivated by the fact that the hydrogen molecular spectra will not be used for ITER operation diagnostics because of difficulties of their interpretation.
- ПубликацияТолько метаданныеBallistic model of recycling of atomic and molecular hydrogen and its application to the ITER main chamber(2021) Neverov, V. S.; Shurygin, V. A.; Kukushkin, A. B.; Kukushkin, A. S.; Lisitsa, V. S.; Pshenov, A. A.; Кукушкин, Александр Борисович; Лисица, Валерий Степанович© 2021 IOP Publishing LtdA simple, computationally efficient 1D model is suggested for the recycling of atomic and molecular hydrogen between the main chamber first wall (FW) of a tokamak and the peripheral plasma. The model is based on iteratively solving the kinetic equation for the 1D velocity distribution function (VDF) of hydrogen neutral atoms in the projection of velocity on the direction normal to the FW. The model results in a fast-converging routine due to the domination of the contribution to the VDF from long-distance, ballistic flights of the neutral atoms produced by the charge exchange of colder atoms with hotter plasma ions. The proposed modification of the ballistic model (BM) enhances its original version along the following lines: the account of the inelastic reflections of the neutral atoms from the wall; parameterisation of the boundary condition for the VDF of the atoms produced by the reflection of ions from the wall with immediate recombination, without capture in the wall and thermalisation there; extension to a mixture of hydrogen isotopes; elaboration of algorithms for speeding up computation on graphical processing units. The complete set of equations of the BM is published for the first time. The model is verified by comparison with the EIRENE code simulations of the VDF of neutral atoms and molecules in the scrape-off-layer around mid-plane for typical conditions of ITER operation. The applicability of the BM to the synthetic diagnostics developed for the H-alpha high-resolution spectroscopy is demonstrated. That is, the simple 1D model reproduces reasonably well the 1D projection of the data computed with the 3D Monte-Carlo code on a 2D plasma background.
- ПубликацияТолько метаданныеSimilarity Laws for the Green Function of the Nonstationary Superdiffusive Transport: Levy Walks and Levy Flights(2021) Kukushkin, A. B.; Kulichenko, A. A.; Sokolov, A. V.; Кукушкин, Александр БорисовичWe obtain an analytic description of the excitation front propagation in a medium during nonstationary superdiffusive (nonlocal) transport in the case of a finite fixed velocity of perturbation carriers (so-called Levy walks with stops). This problem embraces phenomena such as resonance radiation transport in astrophysical gases and plasma, biological migration, and energy transfer by waves in a plasma. In this approach, the result obtained by integrating the exact solution to the kinetic equation for the Green function is independent of the coordinate space dimensionality. The results are compared with data obtained using another more exact method of determining the front and with the results of numerical calculations of the statistics of trajectories using the Monte Carlo method. Comparison demonstrates the applicability of our results in a wide range of parameters of the problem. We propose a universal description of the perturbation front dynamics in the medium for an arbitrary (including infinitely high) fixed velocity of perturbation carriers. This corresponds to the combination of expressions for the front in the case of transport by Levy flights and by Levy walks. We consider the criteria of transition between these regimes of the superdiffusive transport, which corresponds, in particular, to the account for the finite velocity of light in the superdiffusive transport of resonance radiation in gases and plasmas. For Levy walks, we have obtained a relation between the integral characteristic of perturbation of the medium and its carriers.
- ПубликацияОткрытый доступТЕРМОДИНАМИЧЕСКАЯ НЕРАВНОВЕСНОСТЬ РЕЦИКЛИНГА ВОДОРОДА В ПРИСТЕНОЧНОЙ ПЛАЗМЕ ТОКАМАКА И ЕЕ ВЛИЯНИЕ НА ПЕРЕЗАРЯДОЧНУЮ СПЕКТРОСКОПИЮ В ИТЭР(НИЯУ МИФИ, 2023) КУКУШКИН, А. Б.; КУКУШКИН, А. С.; ЛЕВАШОВА, М. Г.; ЛИСИЦА, В. С.; НЕВЕРОВ, В. С.; ПШЕНОВ, А. А.; СДВИЖЕНСКИЙ, П. А.; ТОЛСТИХИНА, И. Ю.; ХУСНУТДИНОВ, Р. И.; СЕРОВ, С. В.; ТУГАРИНОВ, С. Н.; Хуснутдинов, Радмир Ильдарович; Кукушкин, Александр Борисович; Лисица, Валерий СтепановичТермодинамическая неравновесность рециклинга изотопов водорода в пристеночной плазме токамака состоит в существенном отклонении функции распределения по скоростям (ФРС) нейтральных атомов изотопов водорода от однотемпературной максвелловской ФРС. Такое отклонение впервые обнаружено в спектроскопических измерениях излучения плазмы в линиях бальмеровской серии водорода и дейтерия в токамаке Т-3 [1]. В настоящей работе проанализировано влияние указанной термодинамическая неравновесности на пассивный сигнал перезарядочной спектроскопии (CXRS-диагностики) периферийной плазмы в токамаках на примере ожидаемых условий в токамаке ИТЭР.
- ПубликацияТолько метаданныеAssessing global beryllium erosion via tomographic reconstruction of 3D beryllium emission profiles in ITER(2024) Neverov, V. S.; Pitts, R. A.; Khusnutdinov, R. I.; Kukushkin, A. B.; Хуснутдинов, Радмир Ильдарович; Кукушкин, Александр Борисович
- ПубликацияОткрытый доступПРИМЕНЕНИЕ БАЛЛИСТИЧЕСКОЙ МОДЕЛИ BM1D2V ДЛЯ ОЦЕНКИ РАСПЫЛЕНИЯ МАТЕРИАЛА ПЕРВОЙ СТЕНКИ ТЕРМОЯДЕРНОЙ УСТАНОВКИ(НИЯУ МИФИ, 2024) ХУСНУТДИНОВ, Р. И.; ЕФИМОВ, Н. Е.; ГАСПАРЯН, Ю. М.; КУКУШКИН, А. Б.; Ефимов, Никита Евгеньевич; Гаспарян, Юрий Микаэлович; Хуснутдинов, Радмир Ильдарович; Кукушкин, Александр БорисовичЗадача оценки эрозии первой стенки является критической при управлении термоядерной установкой. Для прогнозирования процессов эрозии важно создание быстрого кода расчета рециклинга изотопов водорода в пристеночной плазме, который был бы протестирован путем сравнения с сложными численными кодами, наиболее успешным примером такого рода является код EIRENE [1]. В настоящей работе приведены результаты использования такого быстрого численного кода BM1D2V [2], основанного на полуаналитической баллистической модели [3, 4], соответствующей быстрому коду BM1D1V [5]. Сейчас код BM1D2V дополнен модулем, позволяющим оценить распыление материала первой стенки атомами водорода в пристеночной плазме.
- ПубликацияТолько метаданныеNew Approach to Cross-Correlation Reflectometry Diagnostics of Nonlocality of Plasma Turbulence(2022) Kukushkin, A. B.; Kulichenko, A. A.; Кукушкин, Александр БорисовичOne of the most important properties of stochastic nonlinear processes, including the turbulence of the hydrodynamic motion of continuous media, is distant spatial correlations. To describe them, an approach was proposed by Shlesinger and colleagues based on a linear integro-differential equation with a slowly decaying kernel, which corresponds to superdiffusion (nonlocal) transfer in the regime of Lévy walks (Lévy flights when the finite velocity of the carriers is taken into account). In this paper, we formulate a similar approach that makes it possible to formulate the problem of determining these properties from the scattering spectra of electromagnetic (EM) waves and cross-correlation reflectometry. A universal description of the relationship between the observed symmetric quasi-coherent component in the spectrum of scattered EM waves in plasmas and a process of the Mandelstam–Brillouin scattering type is obtained. It is shown that the nonlocality of spatial correlations of density fluctuations in a turbulent medium is due to long-free-path carriers of the medium’s perturbations, for which the free path distribution function is described by the Lévy distribution. The effectiveness of the proposed method is shown by the example of the interpretation of the data of cross-correlation reflectometry of EM waves in the radio-frequency range for the diagnosis of turbulent plasma in magnetic confinement devices for axisymmetric toroidal thermonuclear plasma. © 2022, MDPI. All rights reserved.