bluuebunny/crossref_metadata_2025_split huggingface dataset:
Species kinetics in Ar-S2 plasma of the pulsed periodic discharge
Authors: Avtaeva S V 
Published: November 2019

Abstract
The kinetic (0D) model a longitudinal pulsed-periodic discharge in mixtures of sulfur vapor with argon based on solution of the balance equations for plasma species and an equation of the electron energy balance was developed and evolution of species densities was calculated in the discharge at pressure ~ 40 Torr. Radiation spectrum of the discharge is similar to solar spectrum in the wavelength range of 280–600 nm. The discharge plasma is electronegative; a discharge with electropositive plasma is non-stable and can exist during short time in a pulsed mode. As simulation shown densities of all charged and excited species fast increase during 1–1.5 μs after voltage pulse beginning, reach maximal values and then decrease because of diminishing electrons mean energy and density in decreasing field. It is found that density of S2
*(B
3Σ) molecules fast rises during voltage pulse and exceeds densities of other excited species; however when a pulse voltage decreases the density of S2
*(B
3Σ) molecules fast falls while density of resonance excited argon atoms decreases slower. This is the reason for appearance of strong Ar lines together with S2 bands in spectra of the longitudinal pulsed-periodic discharge in argon/sulfur vapor mixtures.
Monte-Carlo simulation of the ionization processes for discharges in the left branch of the Paschen curve
Authors: Grishkov A A , Korolev Yu D , Shklyaev V A 
Published: November 2019

Abstract
The paper deals with the development of the simulation methods applied to the low-pressure discharges in which the reduced electric field E/p is extremely high and there exists a problem for the correct description of the ionization processes in the classical electron avalanches. Here we use the PIC/MC code xoopic for calculation of the impact ionization coefficient α, the electron drift velocity and the electron diffusion coefficient D in the electron avalanches in nitrogen. The range of calculations covers the ratio E/p ≤ 1000 V·(cm·Torr)−1. The simulation method was tested on a simple analytical model of an electron avalanche and showed good agreement in low and moderate E/p. It is shown that in conditions of high E/p the spatial distribution of electrons in the avalanche head based on the concepts of electron mobility during their drift motion and diffusion coefficient is not quite correct. The work confirmed that at the very low pressures pre-breakdown phenomena and the transition to the next stage of high-current breakdown cannot be based on ideas about classical electron avalanches.
Phenomena at the electrode surfaces and localization of the volume discharges in small-sized sealed-off TEA-CO2 lasers
Authors: Kozlov B A , Mai T N 
Published: November 2019

Abstract
The mechanism of localization of volume discharge and limitation of resource in small-sized sealed-off TEA-CO2 lasers are grounded. The main processes which initiate the transition of volume discharge into the local one are connected with autoemissive currents from microinhomogeneities at the cathode surfaces. Maximal resource achieved in TEA-CO2 lasers with electrodes made from materials which more stable to the influence of the volume discharge plasma. There are Mo, Ti, Ta, Nb, W and C (graphite). Lifetime of the small-sized sealed-off TEA-CO2 laser up to 2000 hours using graphite cathodes has been achieved.
High-voltage pulse generators for effective pumping of super-atmospheric pressure CO2-lasers
Authors: Kozlov B A , Makhanko D S , Seredinov V I , Pyanchenkov S A 
Published: November 2019

Abstract
This work is devoted to describing of constructions and main characteristics of some types compact pulse generators with amplitude of voltage pulses up to 200 kV, rise-times about 10 ns and pulse energy per pulse up to 20 J. For reduction of rise-time of high-voltage pulses were used spark-discharge two electrodes commutators (sharpeners) at working pressures up to 100 atm.
Optical and kinetic characteristics of a pulsed discharge in argon with aluminum vapor at atmospheric pressure
Authors: Kurbanismailov V S , Maiorov S A , Ragimkhanov G B , Khalikova Z R 
Published: November 2019

Abstract
Experimental studies of the space-time dynamics of the formation and spectra of optical radiation of a pulsed discharge in argon in external electric and magnetic fields were performed. It was shown that during the formation of a pulsed discharge in argon in the process of diffuse luminescence propagation, cathode spots form on the cathode on it, as evidenced by the presence of lines of electrode material vapor in the plasma emission spectrum. Monte Carlo methods are used to study the kinetic characteristics of the drift of aluminum ions in argon.
Investigation of electron transition into runaway mode in inhomogeneous electric field in various gas media
Authors: Mamontov Yu I , Lisenkov V V , Uimanov I V 
Published: November 2019

Abstract
Transition of field-emitted electrons into the runaway mode is investigated in the region of enhanced electric field determined by the configuration of a microtip on a cathode for various gas media composition and pressure. The research is done using simulation of electron motion in the inhomogeneous electric field with a help of the Monte-Carlo procedure in the 3D configuration. Calculations were carried out for Nitrogen, Hydrogen and CO2:N2:He mixture (1:1:3). It’s shown that passage through a relatively small region of the enhanced field in the vicinity of the micro-spike may substantially facilitate electron transition to the runaway mode. This effect enhances at pressures of greater than 10 atm. In our opinion, the resulting runaway electrons may provide pre-ionization of gas medium and formation of the initial stage of a volume discharge. The results obtained are of interest for studies of the switching properties of ultrahigh pressure gaps and the use of a volume discharge for lasers pumping.
Investigation of plasma ion composition generated by high-power impulse magnetron sputtering (HiPIMS) of graphite
Authors: Oskomov K V , Vizir A V 
Published: November 2019

Abstract
High-power impulse magnetron sputtering (HiPIMS) of graphite is used to increase the density of the plasma (up to 1013 cm−3) and the fraction of ionization of carbon (up to 70 %). It makes possible to increase the ion bombardment of the growing film by applying a negative high-frequency (HF) bias potential to the substrate, which allows deposition of diamond-like (DLC) coatings obtained by subplantation mechanism. The purpose of this research was to measure the ion composition of plasma during HiPIMS of graphite by time-of-flight spectrometer depending on discharge parameters (current, pressure, pulse-width). For any pulse-width (up to 250 μs) increase of discharge current leaded to growth of C+ fraction (up to 60 % for 70 A) that results from more intense sputtering of the graphite cathode. Decrease of argon pressure down to 3×10−4 Torr leaded to reduction of C+ fraction down to 13 %, which is related to less intense sputtering. It can be seen that as the argon pressure in the vacuum chamber increases, the percentage of carbon ions in the flow increases (up to 75 %), which may due to the “cooling” of electrons with increasing pressure - they no longer have enough energy to ionize argon (15 eV), but enough energy to ionize carbon (3.6 eV). Thus, using of time-of-flight analyzing of plasma ion composition generated by HiPIMS of graphite one can choose optimum discharge pressure and current – both of them should be maximized.
Probe diagnostics of the plasma plume created by a magnetic nozzle of an inductively coupled plasma source
Authors: Shumeiko A I , Telekh V D 
Published: November 2019

Abstract
The Air-Breathing Helicon Plasma Thruster, a thruster utilizing ambient air which is suggested to support small spacecraft on very low Earth’s orbits, has been tested successfully. Using a retarding field energy analyser and Langmuir probe, the specific impulse have been confirmed for operating conditions of 1.5 mg·s−1 of air, 50 mPa gas pressure, 120 W of radio-frequency forward power at 13.56 MHz, and a maximum axial magnetic field of 200 G at the 200 km attitude. The inductively coupled plasma and ion beam formed have been characterized axially, and the measured beam velocity is about 1100 km·s−1 for these conditions.
Holographic interferometry for the study of an electric explosion of titanium wires
Authors: Skryabin A S , Pavlov A V , Kartova A M , Telekh V D 
Published: November 2019

Abstract
The paper presents the results of a slow (with a characteristic process time τ ≈ 50–100 μs) electric explosion (in an air medium) of thin (with a characteristic diameter δ ≈ 20–50 μm) titanium wires with holographic interferometry. A characteristic energy input into the wires was varied from 2.5 to 3.0 J·mg−1. The optical scheme of interferometry laser diagnostics was discussed. The formation of the main explosion features (shock front, explosion products, etc.) was registered. An interference shift allowed calculating of changing of a refractive index and a density in different zones of the explosion. The simplest estimations indicated that a density in shock compressed gas was varied from 1.1×1020 to 2.4×1020 cm−3.
Generation of direct and reverse runaway electron beams in atmospheric air using anodes made of different metals
Authors: Tarasenko V F , Baksht E Kh , Rybka D V , Sorokin D A , Kozyrev A V , Kozhevnikov V Yu 
Published: November 2019

Abstract
This study presents results on the generation of runaway electron beams propagating from the cathode in both directions: towards the anode and in the opposite direction. The investigations were carried out in atmospheric air excited by nanosecond voltage pulses of both polarities. In the experiments, anodes made of aluminum, brass, and tantalum were used. It was shown that the amplitude of the current pulse of an electron beam generated in the direction opposite to the anode depends on the atomic number of the metal from which the anode is made. At the same time, it is important to note that for a beam generated in the direction of the anode, such dependence was not observed.
About changes in the physicochemical properties of aqueous solutions used as a liquid electrolyte cathode
Authors: Tazmeev G K , Timerkaev B A , Tazmeev A K 
Published: November 2019

Abstract
The gas discharge between liquid electrolyte cathode and metal anode was experimentally investigated. Aqueous solutions of sodium chloride, potassium chloride, sodium sulfate, sodium hydroxide, and potassium hydroxide were used as the electrolyte cathode. Decrease aqueous solution was compensated by adding distilled water (solvent) in a continuous mode in the discharge burning process. It was found that, despite the significant dilution with a solvent, the specific electrical conductivity of aqueous solutions of alkali metal salts and alkalis varies slightly.
Numerical simulation of the liquid-metal jet formation and droplet pinch-off in the cathode spot of a vacuum arc
Authors: Uimanov I V , Mesyats G A 
Published: November 2019

Abstract
A two-dimensional axisymmetric model has been developed to describe the formation of liquid-metal jet and the droplet pinch-off. These processes occur during the extrusion of the melt from the crater by the pressure of the cathode spot plasma of a vacuum arc. The jet formation has been numerically simulated for a copper cathode in the “inertial” mode of the melt splashing until the first droplet pinch-off. In this case, a jet with a longitudinal velocity gradient is formed. This gradient decreases the diameter of the jet and causes its elongation, resulting in droplet pinch-off. It has been shown that the mechanism of the droplet pinch-off is based on Rayleigh-Plateau instability. The droplet pinch-off time decreases with increasing jet velocity and increases for droplets of larger diameter. The simulation predicted the electrical explosion of the droplet-jet neck at the current density on the droplet surface ≥ 107 A·cm−2.
Forevacuum plasma source of ribbon electron beam with a multi-aperture extraction system
Authors: Klimov A S , Zenin A A , Tu Tran Van , Bakeev I Yu 
Published: November 2019

Abstract
The article presents the results of modernization of the accelerating interval of the forvacuum plasma electron source. The source generates an electron beam in the form of a sheet at pressures of 10–30 Pa. To increase the homogeneity, a multi-aperture extraction system was used. The optimal distances between the anode and the extractor, as well as the ratio between the cell sizes of the multi-aperture system, allowing to obtain a homogeneous electron beam width of 30 cm are determined.
Plasma generation in the arc discharge with a thermionic cathode in current stabilization conditions
Authors: Lopatin I V , Akhmadeev Yu H , Koval N N , Kovalsky S S 
Published: November 2019

Abstract
The paper investigates plasma generation in a PINK plasma generator with thermionic and hollow cathodes under stabilizeddischarge current. The possibility of not completely closing of the thermionic electrons current into an external circuit is shown under these conditions. The current of emitted from the thermionic cathode electrons mostly closes inside the device, thus increasing the thermal and current load on the electrodes under such conditions. At this, the current direction in the hollow cathode circuit may change, which has no effecton external circuits. It is further shown that the redistribution of currents in the electrode circuits depends on the discharge conditions (including thermionic cathode heating current and voltage, as well as operating pressure and type of working gas), which, in turn, have influence on the instantaneous potentials of the cathode electrodes. Studies of the main plasma characteristics in different phases of the thermionic cathode heating current and under different plasma generation conditions have shown that changing the current direction in the hollow cathode circuit has in significant influence on the instantaneous values of the main plasma parameters, however, plasma generation is not optimalunder these conditions.
Deuterium ion beam formation in a vacuum arc discharge system with a deuterated cathode
Authors: Nikolaev A G , Frolova V P , Oks E M , Savkin K P , Shandrikov M V , Yushkov G Y 
Published: November 2019

Abstract
The formation of deuterium ion beams in a vacuum arc with a deuterium-saturated zirconium cathode was studied using a MevvaV.Ru vacuum arc ion source. The multi-aperture ion-optical system of the source was replaced by a string ion-optical system to measure and compare the current–voltage characteristics and current density distributions over the beam cross-section obtained with the two systems. The study shows that the string system with a deuterated cathode provides a beam current 1.4–1.5 times higher than the multi-aperture system does, all other things being equal, and that the beam divergence with the string system is also higher. The total pulse current of deuterium ions in the beam ranges to about 1 A.
Unipolar and bipolar mode of deep oscillation magnetron sputtering
Authors: Oskirko V O , Zakharov A N , Pavlov A P , Grenadyorov A S , Semenov V A 
Published: November 2019

Abstract
The paper presents the results of a study of the modes of dual deep oscillation magnetron sputtering. The use of packet pulse discharge power supply allowed to provide a high power density on the surface of the Al target 60–500 W·cm−2 and the ion current density on the substrate 4–20 mA·cm−2 during the duration of the macro pulse – 1 ms. In addition to the parameters of a pulsed power supply, the way of connecting the power source to the dual magnetron sputtering system and the vacuum chamber changed during the experiments. Targets of the magnetron sputtering system were isolated from the chamber or alternately connected to it. A change in the connection method led to a change in the anode area and such discharge parameters as: discharge current, plasma concentration, bias voltage, and ion current density on the substrate. It is shown that in the mode with a small area of the anode, the substrate is exposed to a higher energy impact in comparison with the regime when the anode had a large area.
Triggered gas switch with a sharply non-uniform electric field at the electrode with negative potential
Authors: Alexeenko V M , Zherlitsyn A A , Kokovin A O , Kondratiev S S , Kozyrev A V , Kumpyak E V 
Published: November 2019

Abstract
The paper presents the results of studies for two triggered high-pressure gas switches intended for pulse-periodic capacitive storages with the stored energy level of about 100–1000 J. The operating voltage of the first switch is up to 50 kV, for the second switch is over 200 kV. A feature for both switches is a configuration with a sharply non-uniform field at the electrode with negative potential. In the charging process of a capacitive energy storage, a corona-streamer discharge occurs in the switch, the current of which increases with increasing voltage. Cathode discharge plasma shields a sharp cathode edge and local areas of inhomogeneity with increased emission and also gives a uniform flow of initiating electrons into the gap of the switch. As a result, conditions in the discharge gap vary slightly from pulse to pulse.
Creating ceramic electrically insulating coating on metal surface
Authors: Bakeev I Yu , Burachevsky Yu A , Yushkov Yu G 
Published: November 2019

Abstract
The present work deals with the problem of creating dielectric (ceramic) coating on the surfaces of conductive materials for endowing them with insulating properties. The coatings have been created using the electron-beam evaporation of aluminum oxide ceramics. A plasma electron source operating in the forevacuum range of pressure (5–100 Pa) have been used as a source of electrons. It has enabled an effective transport of the electron beam onto the ceramic non-conductive surface and its melting and evaporation. During this process, the electric charge brought by the electron beam onto the surface of the ceramic target is completely neutralized by the ions of gas discharge plasma generated by the electron beam along its transport path towards the target.
Thermophysical model of electron beam boriding of carbon steel St3
Authors: Dasheev D E , Smirnyagina N N , Lapina A E , Milonov A S 
Published: November 2019

Abstract
The work aims at developing a thermophysical model of electron-beam boriding of carbon steels. The main attention focuses on the physicochemical processes of the formation of iron borides occurring in the treatment zone by the electron beam. A thermodynamic study of phase equilibria in the systems Fe-B-C-O has been performed. On the basis of numerical calculations of temperature fields it is shown that temperature and time conditions of heating and cooling of steel determine the nature of structural transformations. Strength characteristics of iron boride layers have been determined. Then these layers obtained by different methods and using various source components have been thoroughly compared with each other during the analysis.
Nanostructure formation of hypoeutectic silumin by electronion-plasma methods
Authors: Ivanov Yu F , Gromov V E , Zagulyaev D V , Konovalov S V , Rubannikova Yu A , Petrikova E A , Rygina M E 
Published: November 2019

Abstract
The structure, phase composition and defect substructure of the surface layers of hypoeutectic silumin after the complex processing including the electroexplosion ion plasma alloying by the yttrium oxide powder and the subsequent electron beam processing have been analyzed by the methods of modern physical material science. The complex processing is accompanied by the dissolution of the silicon inclusions and intermetallides and the formation of the submicro- and nanodimensional structure. The modified layer (70 μm) is multielemental and it has the structure of high velocity cellular crystallization.
Preparation of high-voltage vacuum gap surfaces by the glowing discharge
Authors: Kanshin I A , Markov V G 
Published: November 2019

Abstract
The paper presents a method for processing parts and components of high-voltage vacuum gap gas-discharge device (GDD), operating on the basis of the Penning discharge, at the stage of their preparation for manufacturing. This method includes the irradiation of the part surfaces by the flow of inert gas ions obtained from gas discharge plasma. The purpose of treatment is to increase the electrical strength and GDD stability. The results of research are presented.
Influence of ultrasonic field during micro-arc oxidation on the structure and properties of calcium phosphate coatings
Authors: Komarova E G , Kazantseva E A , Sedelnikova M B , Sharkeev Yu P 
Published: November 2019

Abstract
The study of the influence of applied external ultrasound (US) field with varied power of 35 or 100 W during the micro-arc oxidation (MAO) processing on the thickness growth, surface roughness, porosity, sizes of structural elements and structural-phase states of the calcium phosphate (CaP) coatings on the titanium surface was performed. It was shown that the US transmittance through the electrolyte for 10 min of MAO processing had led to the increase of the coating thickness from 50 to 60 µm, the surface roughness from 3 to 4.5 µm, and the cross-section porosity from 27 to 40%. However, under the action of external US there was a destruction of structural elements (spheres with pores) on the coating surface and a filling of pores’ spaces by fragments. That led to the decrease of the surface porosity from 30 to 12%. It was revealed by X-ray diffraction (XRD) that all types of the CaP coatings deposited under external US field and without it were in X-ray amorphous state. However, applied US field had led to the increase of the coating crystallinity with incorporation of CaHPO4 and β-Ca2P2O7 phases.
Formation of the silicon coating on the NiTi substrate by magnetron sputtering
Authors: Krukovskii K V , Kashin O A , Luchin A V 
Published: November 2019

Abstract
The paper studies the regularities of silicon coatings formation on a substrate of an alloy based on nickel titanium using the radio-frequency (RF) magnetron sputtering method. It is shown that the use of the RF magnetron sputtering method allows making a silicon coating with a thickness more than 6 μm. It is determined that treatment time has the main influence on the thickness of a coating. The magnitude of the RF-power level of magnetron sputtering has a smaller effect on the thickness of the emerging coating.
Generation of gas-metal plasma of arc low-pressure discharges and investigation of the deposition mode of wear-resistant nitride coatings
Authors: Krysina O V , Shugurov V V , Prokopenko N A , Kovalsky S S 
Published: November 2019

Abstract
The modes of gas-metal plasma generation are investigated at independent and combined operation of plasma generators of the different construction. The dependences of an ion current on a collector on the current of the arc discharge of plasma sources, on the pressure and on the composition of working gas in the wide ranges of parameters are obtained. The distributions of metal and nitride coatings growth rate along vacuum chamber radius at the use of the system of magnetic plasma flow separation from droplet fraction are revealed. The service properties of the plasma sources of different type are defined. The parameter ranges for the optimum modes of ZrN and ZrNbN coating deposition by vacuum arc plasma-assistance method are revealed. The parameters of gas-metal plasma at simultaneous functioning the different type plasma sources are measured.