Thesis title: "Theory of rapidly occurring processes of interaction of strong electric fields with nonequilibrium electron fluxes in dense gases, semiconductors and vacuum" (19.12.2019)
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Thesis title: "Theoretical models of an electric discharge in a gas and the interaction of a pulsed magnetic field with an electrically conductive particle" (06.03.2008)
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Guest Editorial
In studies of electric discharge in vacuum, a fundamentally new physical mechanism of electrodynamic expansion of cathode plasma was discovered at the delayed breakdown of the vacuum gap. At the moment, the proposed theory represents the only internally consistent phenomenological description of vacuum breakdown, accompanied by anomalous acceleration of ions, the appearance of ions with anomalously high energies (above the voltage applied to the gap, multiplied by the elementary charge). The study of the new mechanism of vacuum gap breakdown also answers how individual multiply charged ionic components move relative to each other. In particular, the reasons for the existing experimental contradictions associated with measuring the velocities of ionic components as a function of charge were explained.
Yao, J., Kozhevnikov, V., Igumnov, V., Chu, Z., Yuan, C., & Zhou, Z. (2024) Plasma Sources Science and Technology, 33 (3), 035006 (DOI: 10.1088/1361-6595/ad34f8)
Kozhevnikov, V.Yu., Kozyrev, A.V., Kokovin, A.O., & Semenyuk, N.S. (2023) Plasma Physics Reports, 49 (11), 1350–1357 (DOI: 10.1134/s1063780x23601256)
Kozhevnikov, V.Yu., Kozyrev, A.V., Igumnov, V.S., Semenyuk, N.S., & Kokovin, A.O. (2023) Fluid Dynamics, 58 (6), 1148–1155 (DOI: 10.1134/s0015462823601900)
As a result of joint theoretical research with the Laboratory of Applied Electronics of the Institute of High Current Electronics SB RAS (Tomsk, Russia), an explanation was given for the experimental phenomenon of the increase in the average ion current density on the substrate during the transition from the traditional HiPIMS form to the short-pulse and ultra-short-pulse form of the high-current magnetron discharge. The theory used zero-dimensional spatially averaged models (IRMs) adapted for magnetron discharges with pulse durations less than 25 μs. In the short-pulse mode, the main fraction of positive ions of the discharge plasma are transported to the substrate in the interval between pulses, i.e., in the afterglow phase. When maintaining a constant value of the average discharge power and reducing the pulse duration from 100-500 μs to 5 μs, the average value of the total ion current density on the substrate increases three or more times, depending on the shape and material of the target, current parameters and discharge voltage. The theoretical results are confirmed with high accuracy by experimental observations. The current state of the proposed theoretical model with spatial averaging is of great practical significance for developing magnetron sputtering systems.
For the first time, a comprehensive explanation was given of a new, unique phenomenon of plasma physics - an apokampic discharge (or apokamp), previously discovered experimentally at the Laboratory of Optical Radiation of the Institute of High Current Electronics SB RAS (Tomsk, Russia). Apokamp became known as a non-convective extended plasma jet that arises in gaseous media by adding electronegative components at the bend of a high-frequency discharge of a special configuration. The proposed theory is the first and only physical theory of this phenomenon to date. It not only describes the reasons for the emergence of the “apokamp”, but also allows us to answer several fundamental questions related to what gas environments an apokamp discharge can exist in, how quickly a plasma jet appears, and what is the rate of its growth, and also to find out why the apokamp does not require gas-dynamic flows for its emergence and development.
In the course of experimental and theoretical studies, together with the Laboratory of Optical Radiation of the Institute of High Current Electronics SB RAS (Tomsk, Russia), it was established that in high-pressure gas discharges, there are flows of runaway electrons with kinetic energies significantly exceeding the amplitude voltages at the gas-discharge gap (related to the value of the elementary charge). They are called electrons having “anomalously high energies” or, for short, “anomalous electrons”. Experimental studies were based on measuring the energy characteristics of electrons behind a collector (anode) made of absorbing foils of various thicknesses. To reconstruct the energy spectra, the Tikhonov regularization method was used to solve an ill-posed problem. Theoretical work included the formulation of hybrid fluid-kinetic and fully kinetic models of discharge gaps with high spatial heterogeneity factors. As a result, a consistent self-consistent theoretical apparatus was proposed that makes it possible to calculate the energy spectrum of runaway electrons in any discharge cross-section and obtain the distributions of concentrations and current densities of charged particles in the discharge plasma. This theory was the first to predict the detailed dynamics of a small fraction of “anomalous electrons” in the discharge and explained the reasons for its appearance from first principles.
J. Yao, V. Kozhevnikov, V. Igumnov, Z. Chu, C. Yuan, Z. Zhou — The novel collisionless mechanism of a cathode plasma expansion at the initial stage of a vacuum breakdown. // 2024 IEEE International Conference on Plasma Science (ICOPS), 16-20 June, Beijing, China (DOI: 10.1109/icops58192.2024.10627390)
Z. Liu, V.S. Igumnov, V.Y. Kozhevnikov, C. Yuan — Numerical simulation of microwave gas discharge switch of S-band microwave pulse compressor with trigatron ignition. // 2024 IEEE International Conference on Plasma Science (ICOPS), 16-20 June, Beijing, China (DOI: 10.1109/icops58192.2024.10627280)
V.S. Igumnov, V.Y. Kozhevnikov, Z. Liu, C. Yuan — Model of the formation of a plasma channel in the gas-discharge tube of a microwave switch in a high-power microwave compressor. // 2024 IEEE International Conference on Plasma Science (ICOPS), 16-20 June, Beijing, China (DOI: 10.1109/icops58192.2024.10626505)
V.S. Igumnov, V.Y. Kozhevnikov, Z. Liu, C. Yuan — Numerical simulation of the gas-discharge tube of a microwave switch of the S-band Microwave Pulse compressor at low and high-power levels. // 2024 IEEE International Conference on Plasma Science (ICOPS), 16-20 June, Beijing, China (DOI: 10.1109/icops58192.2024.10626614)
J. Yao, V.Y. Kozhevnikov, V. Igumnov, Z. Chu, C. Yuan, and Z. Zhou — The kinetic theory of cathode plasma expansion in a spatially non-uniform geometric configuration of a vacuum diode. // Plasma Sources Science and Technology, vol. 33, no. 3, p. 035006, 2024 (DOI: 10.1088/1361-6595/ad34f8)
V.Yu. Kozhevnikov, A.V. Kozyrev, A.O. Kokovin, and N.S. Semenyuk — Kinetic Model of Vacuum Plasma Expansion in a Cylindrical Gap. // Plasma Physics Reports, vol. 49, no. 11, pp. 1350–1357, 2023 (DOI: 10.1134/s1063780x23601256)
V.Yu. Kozhevnikov, A.V. Kozyrev, V.S. Igumnov, N.S. Semenyuk, and A.O. Kokovin — Kinetic Theory of Expansion of Two-Component Plasma in a Plane Vacuum Diode. // Fluid Dynamics, vol. 58, no. 6, pp. 1148–1155, 2023 (DOI: 10.1134/s0015462823601900)
V.Y. Kozhevnikov, A.V. Kozyrev, V.F. Tarasenko, A.O. Kokovin, E.K. Baksht, N.P. Vinogradov — Key Modes of Ignition and Maintenance of Corona Discharge in Air. // Energies, vol. 16, no. 13, p. 4861, 2023 (DOI: 10.3390/en16134861)
V. Oskirko, V.Y. Kozhevnikov, S. Rabotkin, A. Pavlov, V. Semenov, and A. Solovyev — Ion current density on the substrate during short-pulse HiPIMS. // Plasma Sources Science and Technology, vol. 32, no. 7, p. 075007, 2023 (DOI: 10.1088/1361-6595/acdd95)
V.Y. Kozhevnikov, A.V. Kozyrev, A.O. Kokovin, and V.S. Igumnov — Numerical Simulation of Fast Atmospheric Electric Discharge in the Tip-to-Plane Configuration. // Proceedings of the 4th International Conference on Modern Approaches in Science, Technology & Engineering (DOI: 10.33422/4ste.2019.02.09)
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