Персона: Синельников, Дмитрий Николаевич
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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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Синельников
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Дмитрий Николаевич
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- ПубликацияТолько метаданныеOverheating of Nanostructured Tendril Bundles due to Thermo-Field Emission(2020) Hwangbo, D.; Kajita, S.; Ohno, N.; Sinelnikov, D.; Bulgadaryan, D.; Efimov, N.; Kulagin, V.; Kurnaev, V.; Синельников, Дмитрий Николаевич; Ефимов, Никита Евгеньевич; Кулагин, Владимир Владимирович© 2021 IEEEField emission current accompanied by visualization of emission sites distribution was measured for nanostructured tendril bundles (NTB) on a tungsten surface. These structures are formed in linear simulators of plasma-surface interaction under helium plasma irradiation with Ne or N2 mixture, and unipolar arcing is often observed for such surfaces. It was shown that field emission current from NTB could be stable for a long period under constant electric field making these structures promising to use as flat cold cathodes. A numerical model was developed for calculating the thermo-field emission current and for checking the possibility of self-heating of the structures depending on their shape. Critical electric field values that lead to self-heating were estimated for different NTB shapes and compared with experimental results.
- ПубликацияТолько метаданныеBuilt-In Surface Analyzer for Plasma Devices with Magnetic Field(2019) Bulgadaryan, D. G.; Sinelnikov, D. N.; Sorokin, I. A.; Kurnaev, V. A.; Efimov, N. E.; Синельников, Дмитрий Николаевич; Сорокин, Иван Александрович; Ефимов, Никита Евгеньевич© 2019, Pleiades Publishing, Ltd.The erosion and redeposition processes of plasma-facing materials in fusion devices are the most important factors affecting near-wall and core plasma parameters and device lifetime. To determine the possibility of in situ analyzing these processes, we developed an experimental model of a built-in surface analyzer utilizing low-energy proton scattering spectroscopy. The results of experimental approbation of the method are presented.
- ПубликацияТолько метаданныеNano-tendril bundles behavior under plasma-relevant electric fields(2021) Hwangbo, D.; Ohno, N.; Kajita, S.; Kulagin, V. V.; Sinelnikov, D. N.; Bulgadaryan, D. G.; Efimov, N. E.; Kurnaev, V. A.; Кулагин, Владимир Владимирович; Синельников, Дмитрий Николаевич; Ефимов, Никита Евгеньевич© 2020 Elsevier LtdThe appearance of unipolar arcs is a negative phenomenon that occurs among plasma-wall interaction processes in thermonuclear devices. Nano-tendril bundles (NTBs) can be formed on a plasma-facing surface of tungsten after irradiation by helium plasma that contains impurities of neon or nitrogen. These structures can increase the probability of unipolar arcing because of significant electron emission under a relatively small applied electric field of several kV/mm. The electron emission can appear due to sufficient field enhancement factor that can be up to several thousand. Furthermore, NTBs can be easily overheated, which leads to initiation of the thermofield emission, consequently triggering explosive emission because of intensive heating by Joule source, even without any additional external power load. This paper shows the results of the field enhancement factor estimations, as well as the critical field strength for NTBs when they can collapse because of explosive electron emission caused by Joule heating. The results were obtained by numerical simulations in COMSOL Multiphysics© and experimentally in a vacuum diode.
- ПубликацияТолько метаданныеApplication of keV-energy proton scattering for thin film analysis(2019) Bulgadaryan, D.; Sinelnikov, D.; Kurnaev, V.; Efimov, N.; Borisyuk, P.; Lebedinskii, Y.; Синельников, Дмитрий Николаевич; Ефимов, Никита Евгеньевич; Борисюк, Петр Викторович; Лебединский, Юрий Юрьевич© 2018 Elsevier B.V. Hydrogen ions are not widely used in low or medium-energy ion scattering spectroscopy. However, in certain cases, the use of non-destructive hydrogen ions with low nuclear stopping may provide additional information compared with noble gas ions. In this work, we describe in situ analysis of nanometer layer deposition of Au on Si and vice versa using keV-energy proton scattering spectroscopy. Ion beam sputtering and thermal evaporation were used for deposition of surface layers. The maximum thickness of deposited layers was measured with X-ray photoelectron spectroscopy and surface profiler. The accuracy of in situ surface layer thickness determination with energy spectra of scattered protons is discussed.
- ПубликацияТолько метаданныеField Emission from Nanostructured Tendril Bundles(2019) Hwangbo, D.; Kajita, S.; Ohno, N.; Sinelnikov, D.; Bulgadaryan, D.; Kurnaev, V.; Синельников, Дмитрий Николаевич© 1973-2012 IEEE.Field emission from tungsten surfaces with nano-tendril bundles formed after exposure to helium plasma with nitrogen or neon impurities was measured using a vacuum diode device. Field enhancement factor and effective emission area were calculated using the Fowler-Nordheim formula and compared for different types of nanostructures. The field enhancement factor for these structures can reach several thousands and the effective emission area can be more than 1000 nm2. Anode luminescence was detected using long-exposure photography and allowed for estimation of current density near the anode. Unipolar arc tracks were observed on the samples with the highest field emission intensity. We show that field emission from nano-tendril bundles is much higher than that from tungsten fuzz or pure tungsten, and fusion-relevant plasma conditions may lead to arc initiation.
- ПубликацияТолько метаданныеUsing Laser-Induced Breakdown Spectroscopy and Mass Spectrometry to Determine the Retention of Deuterium in Titanium Films(2022) Efimov, N. E.; Sinelnikov, D. N.; Sinelnikov,D.N.; Bulgadaryan, D. G.; Gasparyan, Y. M.; Gasparyan,Y.M.; Ефимов, Никита Евгеньевич; Синельников, Дмитрий Николаевич; Гаспарян, Юрий Микаэлович; Вовченко, Евгений Дмитриевич; Крат, Степан Андреевич© 2022, Allerton Press, Inc.Abstract: The sensitivities of laser-induced breakdown spectroscopy and quadrupole mass spectrometry are compared to determine the deuterium retained in titanium films using a nanosecond Nd:YAG laser. Simultaneous measurements are made in the 1–18 J cm−2 range of energy densities. Considerably higher sensitivity of mass spectrometry is revealed, along with the possibility of non-destructive analysis at low energy densities.
- ПубликацияТолько метаданныеEfficiency of hydrogen beam electron stripping using various stripping gases for neutral particle analysis in MEPhIST tokamak(2022) Bulgadaryan, D.; Sinelnikov, D.; Efimov, N.; Синельников, Дмитрий Николаевич; Ефимов, Никита Евгеньевич© 2022Neutral particle analyzers can provide information about ion energy distribution, temperature, and other plasma parameters and are widely used for plasma diagnostics in fusion devices. Most of neutral particle analysis systems require ionization of neutrals, usually implemented by particle transport through thin solid films or a gas. Gas stripping cells are more efficient for ionizing neutrals with energies up to several keV that are expected in MEPhIST tokamak - a small spherical machine being prepared to launch at National Research Nuclear University MEPhI. Here we present the results of investigation of stripping efficiency of various gases for the development of neutral particle analyzer for this tokamak. The measurements were conducted for hydrogen atoms and ions in the energy range 0–5 keV.
- ПубликацияТолько метаданныеThe influence of the adiabatic index on the radiation dynamics of self-similar expanding laser-produced plasma plume(2022) Marenkov, E. D.; Sinelnikov, D. N.; Efimov, N. E.; Bulgadaryan, D. G.; Gasparyan, Y. M.; Маренков, Евгений Дмитриевич; Синельников, Дмитрий Николаевич; Ефимов, Никита Евгеньевич; Гаспарян, Юрий Микаэлович© 2022 Author(s).The radiation dynamics of an adiabatic self-similar expanding spherical plasma plume is considered. It is shown that the radiation intensities evolution strongly depends on the adiabatic index γ. For example, it is proven that the radiation intensity in a highly ionized plasma plume increases over time if γ= 5/3 and has a minimum in time if γ< 5/3. The analytical results are compared to measurements of the radiation from lithium laser-produced plasma. A lithium sample was irradiated by a powerful (42 J/cm2) laser pulse, and radiation of produced lithium plasma was registered by a monochromator. Reasonable agreement with the experiments is reached for γ= 5/4.
- ПубликацияТолько метаданныеChanges in morphology and field emission property of nano-tendril bundles after high temperature annealing(2022) Zhang, R.; Kajita, S.; Hwangbo, D.; Tanaka, H.; Sinelnikov, D.; Синельников, Дмитрий Николаевич© 2022 The AuthorsNano-tendril bundles (NTBs) are known to be formed on tungsten by helium plasma exposure with additional neon impurity gas. In this study, the annealing experiments were conducted at the sample temperature of 1473 – 1673 K to investigate the changes of morphology and field emission property of NTBs. With NTBs formed on a W surface, the surface did not fully recover to a smoothed surface and the NTBs remained the fiber-form structures after the annealing at 1673 K for one hour. In addition, the onset electric field for field emission increased, while the emission current from NTBs significantly decreased after the annealing. When the samples were biased at −250 V during helium plasma exposure, arc ignition was confirmed on W surface with NTBs, whereas no arc ignition appeared on W with annealed NTBs.
- ПубликацияТолько метаданныеOn the Possibility of Surface Analysis by keV-Energy Proton Scattering in Magnetic Fusion Devices(2020) Kurnaev, V.; Bulgadaryan, D. G.; Sinelnikov, D. N.; Синельников, Дмитрий Николаевич© 2020, Pleiades Publishing, Ltd.Abstract: The processes of erosion and redeposition of plasma-facing materials in fusion devices are some of the most important factors affecting the plasma parameters and the resource of the first wall. The method of analyzing thin layers on a surface using keV-energy proton scattering expands the functionality of determining the rate of erosion and deposition of layers with a large atomic number on a substrate of a light element or, conversely, light layers on a heavy substrate, which is typical of modern fusion installations. The analysis of deposition and/or erosion consists in placing special marker targets with the layers of a material with a low atomic number and/or material with a large atomic number in the places of the installation in which it is proposed to study the rate of erosion and/or deposition, with a subsequent analysis of the energy spectra of hydrogen ions reflected from exposed targets with energies in the kiloelectron-volt range. In this paper, estimates of the applicability of this technique directly in a fusion device with regard to the characteristic parameters of the near-edge plasma are given.