Персона: Скобелев, Игорь Юрьевич
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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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Игорь Юрьевич
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- ПубликацияТолько метаданныеMethod for the Precise Measurement of Wavelengths for Main Shell Transitions in He- and Li-like Ca Ions(2020) Ryazantsev, S. N.; Skobelev, I. Y.; Mishchenko, M. D.; Pikuz, S. A.; Скобелев, Игорь Юрьевич© 2020, Pleiades Publishing, Ltd.Abstract: A possible approach to obtain a precise experimental data on the atomic structure of highly charged ions is considered. Since the key point determining measurement accuracy is the presence of reference lines with precisely known wavelengths, it is proposed first to to use hydrogen-like reference lines for precise measurements of the helium-like resonant transition and their dielectronic satellites. Then in turn these lines, which exist in the plasma over a wide temperature range, can be used as the reference in the wavelength measurement for other ions. The problems associated with the creation of the plasma conditions under which the reference and measured lines have comparable intensities are discussed. The irradiation of minerals with laser pulses, which, in terms of their chemical composition, are a set of elements with average 15 < Z < 30 and light Z < 15 nuclear charges, is proposed. Several experimental schemes to measure the wavelengths of the spectral lines of multiply charged calcium ions with an expected error of up to 0.125 mÅ are considered as an example.
- ПубликацияТолько метаданныеFeatures of the generation of fast particles from microstructured targets irradiated by high intensity, picosecond laser pulses(2019) Sedov, M. V.; Faenov, A. Ya.; Andreev, A. A.; Ryazantsev, S. N.; Skobelev, I. Yu.; Pikuz, S. A.; Скобелев, Игорь ЮрьевичCopyright © Cambridge University Press 2019. The use of targets with surface structures for laser-driven particle acceleration has potential to significantly boost the particle and radiation energies because of enhanced laser absorption. We investigate, via experiment and particle-in-cell simulations, the impact of micron-scale surface-structured targets on the spectrum of electrons and protons accelerated by a picosecond laser pulse at relativistic intensity. Our results show that, compared with flat-surfaced targets, structures on this scale give rise to a significant enhancement in particle and radiation emission over a wide range of laser-target interaction parameters. This is due to the longer plasma scale length when using micro-structures on the target front surface. We do not observe an increase in the proton cutoff energy with our microstructured targets, and this is due to the large volume of the relief.
- ПубликацияТолько метаданныеThermalization of the plasma arising during counter collision of high-energy plasma flows in a longitudinal magnetic field(2021) Gavrilov, V. V.; Eskov, A. G.; Zhitlukhin, A. M.; Kochnev, D. M.; Pikuz, S. A.; Ryazantsev, S. N.; Skobelev, I. Y.; Скобелев, Игорь Юрьевич© Published under licence by IOP Publishing Ltd.This work is devoted to the study of thermalization of plasma created by head-on collisions of high-energy plasma flows in a longitudinal magnetic field of 0.5-2 T. Hydrodynamic flows contained the energy of 200 kJ with velocities from 2 × 107 to 4 × 107 cm/s and ion density from 2 × 1015 to 4 × 1015 cm-3 were created inside the 2MK-200 facility by two electrodynamic plasma accelerators equipped by a system of pulsed gas injection. Nitrogen, neon and their mixtures with hydrogen and deuterium were implemented as working gases. A process of plasma creating was investigated by near-wall magnetic probes situated in different parts of the interaction chamber. Temporal evolution of the plasma electron temperature had been traced by x-ray photodiodes covered by different filters. It was discovered that the plasma electron temperature changed insignificantly during 6-8 µs after it reached the maximum value, which means that it ionization state can be considered as quasi-stationary.
- ПубликацияТолько метаданныеInteraction of a high-energy plasma flow with a gas jet in the laboratory(2021) Gavrilov, V. V.; Zhitlukhin, A. M.; Kochnev, D. M.; Kostyushin, V. A.; Pikuz, S. A.; Ryazantsev, S. N.; Skobelev, I. Yu.; Скобелев, Игорь Юрьевич© 2021 47th EPS Conference on Plasma Physics, EPS 2021. All right reserved.The main results of the work are as follows: - When a hydrogen plasma flow interacts with a supersonic gas jet of nitrogen or neon (the maximum density in the gas jet reached 1017cm-3), a plasma layer ≈ 3÷4 cm thick for ≈2÷3 μs is formed, which emits soft X-ray radiation. The displacement velocity in the direction of the plasma flow is ≈ 3×106cm/s. Such a high speed of the radiation source movement under one-sided action on a gas jet puts forward certain requirements for the synchronization of counter-propagating plasma flows in the current experiments on two-sided action on a gas jet. - Line emission spectra of multiply charged ions recorded during the interaction of hydrogen plasma flows with jets of nitrogen or neon made it possible to estimate the electron temperature of the plasma formed in these experiments, which in both cases turned out to be at the level of 40 ± 10 eV. However, it should be noted that observed intense resonance Ne VIII lines can be emitted by a plasma only at a temperature of 70÷100 eV.
- ПубликацияТолько метаданныеThe Role of Stepwise Photoionization in Measurements of the Ionization Potentials in Dense Plasma(2023) Skobelev, I. Y.; Ryazantsev, S. N.; Kulikov, R. K.; Pikuz, S. A.; Скобелев, Игорь Юрьевич; Куликов, Роман КонстантиновичThe interaction of high-contrast high-intensity laser radiation with solids allows us to create hot or warm plasma of solid or even over-solid density, such as in the case of inertial fusion particularly. The multicharged ions contained in it can no longer be considered isolated. As a result, this leads to a decrease in the ionization potentials and to the disappearance of a number of bound ionic states. To describe the ionization potential depression, two major approaches are now used predominantly, where the key parameter is either average interelectronic or interionic distance. Since neither of the approaches can be substantiated purely theoretically, their applicability can only be established by comparison with experimental results. In recent experiments with X-ray free-electron lasers, it was concluded that the ionization potential depression rather depends on the interelectronic distance. However, when measuring ionization potentials, it was assumed that the main role in ionization processes is played by the direct photoionization of the ion ground state. In the present paper, we show that stepwise photoionization processes should play a significant role in dense plasma, disrupting a straight correspondence between the threshold in direct photoionization by X-ray laser photons and the actual ionization potential of multicharged ions. It means that the measurement results mentioned above are not correct, and the main conclusion about the importance of the interelectronic distance for depression of the ionization potential is not correct.
- ПубликацияТолько метаданныеShielding of the tungsten target exposed to the high-energy hydrogen plasma flow by gas injection(2021) Gavrilov, V. V.; Zhitlukhin, A. M.; Kochnev, D. M.; Kostyushin, V. A.; Pikuz, S. A.; Ryazantsev, S. N.; Skobelev, I. Yu.; Скобелев, Игорь Юрьевич© 2021 47th EPS Conference on Plasma Physics, EPS 2021. All rights reserved.Experiments have shown that the injection of a gas (nitrogen/neon) in front of the target surface significantly reduced the heat load of the plasma flow on the target material. The gas shielding effect prevented heating of the target surface to the boiling point and evaporation of tungsten. A decrease in the value of the gas jet parameter n ∙ L down from (2÷4) × 1017 cm-2 led to an increase in the absorbed energy density by the target. Most likely, the tungsten reached the boiling point. However, no characteristic spectral bands of tungsten were observed in the spectra of the target plasma. Further research is required to determine the minimum value of the gas jet parameter n ∙ L, which would be sufficient for the shielding effect.
- ПубликацияТолько метаданныеPrecision Measurements of X-Ray Spectra for the Diagnosis of Laboratory Astrophysical Plasma(2023) Ryazantsev, S. N.; Skobelev, I. Y.; Kuznetsov, A. P.; Kulikov, R. K.; Pikuz, S. A.; Скобелев, Игорь Юрьевич; Кузнецов, Андрей Петрович; Куликов, Роман Константинович; Рязанцев, Сергей Николаевич
- ПубликацияТолько метаданныеAbsolute keV x-ray yield and conversion efficiency in over dense Si sub-petawatt laser plasma(2022) Ryazantsev, S. N.; Martynenko, A. S.; Sedov, M. V.; Skobelev, I. Y.; Pikuz, S. A.; Скобелев, Игорь Юрьевич; Рязанцев, Сергей Николаевич; Седов, Максим ВладимировичLaser-produced plasmas are bright, short sources of X-rays often used for time-resolved imaging and spectroscopy. Absolute measurement requires accurate knowledge of laser-to-x-ray conversion efficiencies, spectrum, photon yield and angular distribution. Here we report on soft X-ray emission from a thin Si foil irradiated by a sub-PW picosecond laser pulse. These absolute measurements cover a continuous and broad spectral range that extends from 4.75 to 7.5 Angstroms (1.7-2.6 keV). The X-ray spectrum consists of spectral line transitions from highly charged ions and broadband emission with contributions from recombination, and free-free processes that occur as electrons decelerate in plasma electromagnetic fields. These quantitative measurements are compared to particle-in-cell simulations allowing us to distinguish bremsstrahlung and synchrotron contributions to the free-free emission. We found that experiment and simulation estimations of laser-to-bremsstrahlung conversion efficiency are in a good agreement. This agreement illustrates the accuracy of experiment and physical interpretation of the measurements.
- ПубликацияОткрытый доступPrecise wavelength measurements of potassium He-and Li-like satellites emitted from the laser plasma of a mineral target(2021) Filippov, E. D.; Martynenko, A. S.; Krus, M.; Renner, O.; Ryazantsev, S. N.; Skobelev, I. Y.; Mishchenko, M. D.; Pikuz, S. A.; Скобелев, Игорь Юрьевич© 2020 Author(s).Atomic models of high-Z multicharged ions are extremely complex and require experimental validation. One way to do so is to crosscheck the predicted wavelengths of resonance transitions in He-and Li-like ions against precise spectroscopic measurements that use the spectral lines of H-like ions for spectra calibration; these reference data can be modeled with outstanding precision. However, for elements with Z of at least 15, it is quite difficult to create a hot dense plasma with a large concentration of H-like charge states. To mitigate this issue, the suggestion here is to use as laser targets particular minerals comprising elements with moderate (between 15 and 30) and low (less than 15) Z, with emission from the latter delivering perfect reference lines over a whole range of He-and Li-like moderate-Z emission under examination. This approach is implemented to measure the wavelengths of resonance transitions (1snp → 1s2 for n = 2, 3) in He-like K ions and their dielectronic satellites by irradiating plates of orthoclase (KAlSi3O8) with 0.5-kJ subnanosecond laser pulses. X-ray spectra of the laser-generated plasma contain the investigated lines of highly charged K ions together with precisely known reference lines of H-like Al and Si atoms. The K-shell spectral line wavelengths are measured with a precision of around 0.3 mÅ.
- ПубликацияТолько метаданныеA Soft X-Ray Radiation Source Formed in Supersonic Argon Gas Jets under the Action of High-Contrast Femtosecond Laser Pulses of Relativistic Intensity(2020) Alkhimova, M. A.; Mishchenko, M. D.; Boldarev, A. S.; Jie, F.; Ryazantsev, S. N.; Skobelev, I. Y.; Pikuz, S. A.; Скобелев, Игорь Юрьевич© 2020, Pleiades Publishing, Ltd.Abstract: The possibility of designing a compact source of soft X-ray radiation without the accompanying generation of fast electrons is under study. The source is formed by the interaction of high-contrast femtosecond laser pulses of relativistic intensity with supersonic argon gas jets. The optimal conditions are found under which the conversion coefficient to soft X-ray radiation in the range of 2.9–3.3 keV reaches 8.57 × 10–5.