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Сергеев, Никита Сергеевич

Организационные подразделения

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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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Сергеев

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Никита Сергеевич

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Теперь показываю 1 - 10 из 21

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Properties of millisecond-scale modulated pulsed power magnetron discharge applied for reactive sputtering of zirconia
(2021) Kaziev, A. V.; Kolodko, D. V.; Sergeev, N. S.; Казиев, Андрей Викторович; Колодко, Добрыня Вячеславич; Сергеев, Никита Сергеевич
The electrical properties of a modulated pulsed power (MPP) magnetron discharge were experimentally and theoretically studied in case of reactive sputtering of metallic zirconium target in argon/oxygen mixtures. The high-power pulsing was assisted by pre-ionization provided by a low-power direct current (DC) magnetron discharge filling the pulse-off period. The ranges of stable discharge operation parameters (applied voltage and oxygen flow rate) were determined for pulse-on time of 3 ms and pulse-off time 100-1000 ms. The maximum stable peak power density was 2.1 kW cm(-2). Strong dependence of the MPP discharge current waveforms on the pulse-off time was found, indicating the important role of the pre-ionizing DC discharge. In presence of oxygen, discharge peak current was observed with characteristic width up to 1.5 ms, followed by non-reactive-like plateau region. For theoretical treatment of the observed discharge current behavior, we modified the well-known Berg model of reactive sputtering by introducing the terms required for adequate description of time-dependent poisoning and sputtering processes. The reactive ion implantation term was also transformed to account for the process saturation at high ion current densities. Calculation results from the modified Berg model demonstrated good agreement between our experimental observations of discharge current evolution and target poisoning dynamics in the timescale of milliseconds.
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Tungsten fuzz annealing effect on deuterium retention in polycrystalline tungsten
(2022) Kanashenko, S.; Harutyunyan, Z.; Ogorodnikova, O. V.; Gasparyan, Y.; Efimov, V.; Sorokin, I.; Sergeev, N.; Арутюнян, Зорий Робертович; Огородникова, Ольга Вячеславовна; Гаспарян, Юрий Микаэлович; Ефимов, Виталий Сергеевич; Сорокин, Иван Александрович; Сергеев, Никита Сергеевич
© 2022 Elsevier B.V.Using a beam-plasma discharge device operating on helium (He), tungsten with the fuzz on the surface (Wf) has been formed by irradiating polycrystalline tungsten (W) samples with He ions with an energy of ∼150 eV and the fluence of ∼6 × 1024 He/m2 at the temperature of 1273 K. The deuterium (D) retention in Wf annealed at different temperatures was studied by thermal desorption spectroscopy (TDS). Before and after annealing at temperatures of 1000,1200,1400 and 1600 K, Wf was irradiated at room temperature by 2 keV D3+(667 eV/D) ions with the fluence of 1021 D/m2, then in-situ TDS was performed after each irradiation. Annealing W above 1200 K clearly changes the retention mechanism of D: the TDS spectrum consisting of multiple peaks changes to an almost single-peak spectrum. Annealing at 1600 K leads to surface smoothing and the decrease of the D retention by a factor of two compared to the annealing at 1000 K. This can be explained by an increase of the reflection coefficient for the flat W surface. However, the D retention in Wf is significantly higher compared to that in W without He plasma exposure even after annealing at 1600 K, because there are still He bubbles in Wf that effectively trap D
Открытый доступ
ЗАМЕЩЕНИЕ ИЗОТОПОВ ГЕЛИЯ В ВОЛЬФРАМЕ ПРИ ПОСЛЕДОВАТЕЛЬНОМ ИОННОМ ОБЛУЧЕНИИ
(НИЯУ МИФИ, 2023) Умеренкова, А. С.; Гаспарян, Ю. М.; Арутюнян, З. Р.; Ефимов, В. С.; Сергеев, Н. С.; Сорокин, И. А.; Остойич, Н.; Остойич, Никола; Гаспарян, Юрий Микаэлович; Умеренкова, Анастасия Сергеевна; Ефимов, Виталий Сергеевич; Сорокин, Иван Александрович; Арутюнян, Зорий Робертович; Сергеев, Никита Сергеевич
Helium isotope exchange in tungsten during sequential irradiation by 3He and 4He ions at room temperature was investigated. Tungsten samples were irradiated in two ways: by 3 keV mass-separated ion beams, or by low energy ions in plasma discharge. The He amount in W after irradiation was measured using ex-situ (up to 2500 K) thermal desorption spectroscopy. Despite the very high binding energy of He with lattice defects in W, a very high efficiency of He isotope exchange was observed.
Только метаданные
Characterization of millisecond-scale high-power impulse magnetron discharge in helium
(2020) Kaziev, A. V.; Kolodko, D. V.; Kharkov, M. M.; Rykunov, G. I.; Sergeev, N. S.; Tumarkin, A. V.; Казиев, Андрей Викторович; Колодко, Добрыня Вячеславич; Харьков, Максим Михайлович; Сергеев, Никита Сергеевич; Тумаркин, Александр Владимирович
© 2021 IEEEImpulse magnetron discharges with millisecond-scale pulses-extended duration modes of technological high-power impulse magnetron sputtering (HiPIMS)-have promising applications in pulsed plasma facilities of different kinds due to high ionization degree (up to 90%), suitable duration, and scalable hardware design. Depending on operating conditions, at the same power level, two distinct diffuse regimes can be distinguished: the one with intense target sputtering-long HiPIMS (L-HiPIMS),-and the non-sputtering low-voltage one (non-sputtering magnetron discharge). The majority of existing studies of these discharge forms were made for argon working gas. For a number of prospective high-power pulsed plasma applications (e. g. pulsed plasma accelerators and thrusters), however, the option of using light gases is preferable. Here, the operation of a millisecond-scale impulse magnetron discharge (L-HiPIMS) in helium has been examined. The plasma parameters (electron density, electron temperature) were measured in a time-resolved fashion with a Langmuir probe. The electrical measurements were accompanied with optical emission spectroscopy. The use of the long pulsed modes enables achieving high plasma density and accelerating the ion flux with a peak energy of ~ 10 eV.
Открытый доступ
МОДИФИКАЦИЯ ПОВЕРХНОСТИ ВОЛЬФРАМА ПОД ВОЗДЕЙСТВИЕМ ГЕЛИЕВОЙ ПЛАЗМЫ С ПРИМЕСЬЮ ИНЕРТНЫХ ГАЗОВ
(НИЯУ МИФИ, 2022) СЕРГЕЕВ, Н. С.; СОРОКИН, И. А.; ПОДОЛЯКО, Ф. С.; ОГОРОДНИКОВА, О. В.; ЕФИМОВ, В. С.; ГАСПАРЯН, Ю. М.; САВЕЛЬЕВ, М. Д.; Огородникова, Ольга Вячеславовна; Гаспарян, Юрий Микаэлович; Подоляко, Федор Сергеевич; Сорокин, Иван Александрович; Ефимов, Виталий Сергеевич; Савельев, Максим Дмитриевич; Сергеев, Никита Сергеевич
Одним из приоритетных направлений в области термоядерных исследований является контроль уровня плазменно-тепловой нагрузки на внутрикамерные элементы установок магнитного удержания горячей плазмы. Постепенное развитие технологии напуска примеси инертного газа (He, Ne, Ar) в процессе плазменного разряда в установках типа токамак и стелларатор [1, 2] как средства радиационного охлаждения периферии плазмы, предъявляют новые требования по контролю состояния поверхности обращённых к плазме элементов.
Только метаданные
Magnetic Component of Quasi-coherent Mode of Plasma Fluctuations in Ohmic Plasma of the T-10 Tokamak
(2024) Sergeev, N. S.; Melnikov, A. V.; Eliseev, L. G.; Сергеев, Никита Сергеевич; Мельников, Александр Владимирович
Только метаданные
Measurements of secondary electron emission yield in the linear plasma simulator BPD-PSI
(2023) Sorokin, I. A.; Sergeev, N. S.; Сорокин, Иван Александрович; Сергеев, Никита Сергеевич
Только метаданные
Comparison of thermal properties of a hot target magnetron operated in DC and long HIPIMS modes
(2021) Kaziev, A. V.; Kolodko, D. V.; Tumarkin, A, V.; Kharkov, M. M.; Lisenkov, V. Y.; Sergeev, N. S.; Казиев, Андрей Викторович; Колодко, Добрыня Вячеславич; Тумаркин, Александр Владимирович; Харьков, Максим Михайлович; Сергеев, Никита Сергеевич
© 2021 Elsevier B.V.Thermal properties of the magnetron discharge with uncooled copper and chromium targets were studied experimentally and theoretically for DC and long HiPIMS (L-HiPIMS) operation modes. A set of thermal fluxes was considered to build a numerical model of the hot target exposed to DC and high-power pulsed plasma. The modeling results were tested in the experiments. The temperature of targets was measured directly in course of magnetron discharge operation with an elaborated contact thermocouple method. The measurements were made in two modes. At first the temporal evolution of temperature was recorded for a fixed applied discharge power. The results were found to well agree with temperature values expected from calculations. At 2 kW power, it takes ~50 s to reach the melting point of copper. The steady-state temperature values were also measured for a number of discharge power levels. The obtained dependence clearly demonstrated that the main mechanisms of the target heat balance at high temperatures are surface radiation and heat transfer due to thermal conductivity of the heat insulation supports between the target and water-cooled cathode. The parameters of DC hot target magnetron were compared to the high-power pulsed regime with the pulse-on time 20 ms. A promising method of a hot target magnetron discharge operation was considered that involves applying long (>20 ms) high-power pulses to the target pre-heated in the DC mode during the pulse-off period.
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A new compact linear beam-plasma discharge simulator BPD-PSI
(2022) Sergeev, N. S.; Sorokin, I. A.; Podolyako, F. S.; Сергеев, Никита Сергеевич; Сорокин, Иван Александрович; Подоляко, Федор Сергеевич
A new BPD-PSI line-type plasma simulator is introduced. The device features two vacuum units: a target unit and an electron gun unit, connected to each other by a water-cooled electron beam transport channel. The Pierce-type electron gun is used to generate stationary or pulsed electron beam, utilized for beam-plasma discharge generation. The plasma electron density can be varied in the range of n e = 1 × 1016 - 1 × 1018 m-3 with electron temperature in the range of T e = 1-20 eV. The ion flux of 1 × 1021 m-2 s-1 and heat fluxes up to 5 MW m-2 are obtained. A set of utilized plasma and plasma-surface interaction diagnostics are described. Five demonstration experiments are presented: 1) high vs low power beam-plasma operation, 2) beam-plasma discharge with/without presence of an external magnetic field, 3) incident ion flux composition analysis, 4) incident ion energy distribution function measurement, 5) in-situ target surface temperature control and in-vacuo thermal desorption spectroscopy measurement. All of the technical features of the setup described in this paper make it a new tool for studying plasma-surface interactions. © 2022 IOP Publishing Ltd and Sissa Medialab.
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HYDROGEN AND HELIUM DISCHARGES IN THE GOLEM TOKAMAK РАЗРЯДЫ В ВОДОРОДНОИ И ГЕЛИЕВОИ ПЛАЗМЕ ТОКАМАКА GOLEM
(2021) Sarancha, G. А.; Emekeev, I. A.; Kropackova, D.; Kulagin, V. V.; Drozd, A. S.; Ganin, S. A.; Kudashev, I. S.; Melnikov, A. V.; Sergeev, N. S.; Дрозд, Алексей Станиславович; Мельников, Александр Владимирович; Сергеев, Никита Сергеевич
© 2021 National Research Center Kurchatov Institute. All rights reserved.The helium plasma properties and confinement remain an important area of research in modern fusion devices. This work is dedicated to the helium plasma initiation and control in a small-scale tokamak GOLEM compared to hydrogen plasma. Helium and hydrogen plasmas are comprehensively compared and the optimum operational conditions for the start-up are found. Long-range correlations between low-frequency (<50 kHz) electrostatic and magnetic oscillations are found, as well as broadband (<250 kHz) magnetic oscillations resolved in frequency and wave vector in helium plasma.