Персона: Акишев, Юрий Семенович
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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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- ПубликацияТолько метаданныеEffect of High-Voltage Electrode Potential Bias on the Breakdown Induced by Ionization Wave in Discharge Tube(2020) Meshchanov, A. V.; Ionikh, Y. Z.; Akishev, Y. S.; Акишев, Юрий Семенович© 2020, Pleiades Publishing, Ltd.Abstract—: An experimental study has been done of the bias effect of the active (high-voltage) electrode potential on the breakdown characteristics in a discharge tube 15 mm in diameter, filled with neon, argon, or their mixture (3 : 1) at a pressure of ~1 Torr. The bias of the potential is carried out by parallel connection to the electrode with an additional constant voltage or additional pulses with an amplitude less than the voltage for maintaining self-sustained discharge. In this case, a change in the breakdown voltage, the velocity of the pre-breakdown ionization wave, and the brightness of radiation from its front is observed. In particular, the breakdown voltage can increase up to 1.5–2 times, and this state of the discharge gap can be maintained for tens of minutes. The observed effects are assumed to be caused by the appearance of a charge on the tube wall and a change in its potential near the electrode, which affect the characteristics of the primary breakdown between the electrode and the wall and, in turn, the processes of discharge ignition. The mechanisms of appearance of the surface charge on the wall when feeding a bias voltage to electrode are investigated.
- ПубликацияТолько метаданныеOn the Development of Ionization Waves Preceding Breakdown in a Long Capillary Tube Filled with Helium at Low Pressure(2021) Karal'nik, V. B.; Petryakov, A. V.; Ionikh, Y. Z.; Akishev, Y. S.; Акишев, Юрий Семенович© 2021, Pleiades Publishing, Ltd.Abstract: Experiments that revealed the main trends in the development of complete breakdown in a long capillary tube for different electrode configurations are reported. It is demonstrated that, in the presence of an additional external electrode around the tube, a fast stage completing the breakdown is preceded by a slow stage caused by development of a weak-current surface barrier discharge inside the tube. This discharge is realized due to propagation of forward (from the high-voltage electrode) and backward (from the grounded electrode) surface ionization waves. The presence of preliminarily, locally deposited charge of the sign opposite to polarity of the voltage pulse leads to acceleration of propagation of ionization waves in the tube. In the absence of the external electrode, the breakdown occurs much faster but is characterized by a large scatter in the delay time (up to complete lack of breakdown) relative to the applied voltage pulse. Unstable operation of the gas-discharge device determined by development of breakdown represents a much more serious problem in many applications compared to the situation in which it turns on slowly but stably. Therefore, the results demonstrating the possibility of controlling the breakdown are of great scientific and practical value.
- ПубликацияТолько метаданныеRadial current distribution along the ionization wave propagating in a long dielectric capillary tube filled with a low-pressure helium(2021) Karalnik, V. B.; Petryakov, A. V.; Akishev, Y. S.; Акишев, Юрий Семенович© 2021 Institute of Physics Publishing. All rights reserved.The experimental results on the study of the ionization wave propagating along a long capillary tube are presented. The ionization wave was initiated by high-voltage pulse of positive or negative polarity. The propagation of this surface ionization wave precedes and influences the establishment of complete electric breakdown within the tube. The spreading of this wave is accompanied by the surface charge deposition. The usage of the fine-sectioned outer electrode allows one to find out the general features of the ionization waves.
- ПубликацияТолько метаданныеIonization wave propagation in a long capillary tube in the presence of a low-current glow discharge in low-pressure helium(2021) Karalnik, V. B.; Petryakov, A. V.; Akishev, Y. S.; Акишев, Юрий Семенович© 2021 Institute of Physics Publishing. All rights reserved.The experimental results on the study of the positive ionization wave propagating along a long capillary tube are presented. The ionization wave was initiated by eigther highvoltage pulse of positive polarity applied over a long capillary tube with helium or high-voltage pulse applied over the same tube but in presence of low-current glow discharge. The spreading of this wave is accompanied by the surface charge deposition. The usage of the fine-sectioned outer electrode allows one to find out the features of the positive ionization wave in both cases (with or without low-current discharge).
- ПубликацияТолько метаданныеThe Memory Effect of Microdischarges in the Barrier Discharge in Airflow(2020) Usenov, E. A.; Petryakov, A. V.; Ramazanov, T. S.; Gabdullin, M. T.; Akishev, Y. S.; Акишев, Юрий Семенович© 2020, Pleiades Publishing, Ltd.Abstract: The paper devoted to the research of the microdischarge dynamics in the dielectric barrier discharge. The discharge between rail electrodes in airflow along the electrodes at atmospheric pressure was studied. The aim of this work is to clarify the role of volume plasma and surface charges in the memory effect of microdischarges. Based on the analysis of microdischarge images obtained using high-speed camera, it is established that the transport of microdischarge plasma by a gas flow determines the microdischarge localization in each subsequent half-cycle of the applied voltage. An important part is played by the turbulence and the presence of vortices in the airflow. They determine both the speed of plasma channel transfer and the probability of the microdischarge appearence in a specific half-cycle. The results of the work show the possibility of the gas-dynamic control for parameters of a barrier discharge.
- ПубликацияТолько метаданныеFormation of Extended Tubular Plasma in Argon at Low Pressure and in a Weak Longitudinal Magnetic Field(2024) Akishev, Y. S.; Bakhtin, V. P.; Buleyko, A. B.; Loza, O. T.; Акишев, Юрий Семенович
- ПубликацияТолько метаданныеPin-to-plane self-pulsing discharge in transversal airflow: interaction with a substrate of plasma filaments blown out from the discharge zone(2020) Akishev, Y. S.; Balakirev, A. A.; Grushin, M. E.; Karalnik, V. B.; Акишев, Юрий СеменовичThe pin-to-plane electrode system for the multi-sectioned discharge in the transversal airflow at atmospheric pressure has been developed. The airflow is directed perpendicularly to the electric current. As it was revealed, all sections of the multi-sectioned discharge operate identically and independently to each other. For this reason, the spatial-temporal behavior of the discharge excited only in a single section was investigated. The pin-to-plane discharge (PPD) was powered by a positive polarity DC voltage that induces the spontaneously repeating streamer-spark breakdowns in a discharge gap. Each breakdown forms the plasma filament (PF) which is being further blown out of the discharge zone and stretched by the airflow. The PF impacts a dielectric plate located in the path of the airflow at different distances away from the discharge zone. Two modes in the behavior of the blown-out PF have been revealed. When the plate is close to the discharge zone, the blown-out PF is tightly pressed by the flow to the plate. In this case, both the brightness and electric current of the PF are periodically pulsing with a high frequency up to the plasma filament breaking up due to its strong elongation by the flow. If the plate is far away, the quasistationary regime happens. During the PF elongation in this regime, plasma filament keeps both the brightness and current approximately changeless till the filament breaking up. At In this regime, the blown-out PF is being stretched in parallel to the surface without contacting it. The release of energy into the PF continues also in the course of its blowing out until its impinging the object located in the path of airflow. Due to that, the PPD pulsing mode generates a lot of reactive species inside the PF up to its impinging the object to be treated. This is a reason why the self-pulsing PPD can be highly effective for surface processing by non-thermal plasma.