Journal articles: 'Interaction plasma/cathode'

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Devia Narvaez, D. F., L. F. Alvarez, S. Ramirez Ramirez, and And E. Restrepo-Parra. "Numerical analysis of the cathodic material influence on the arc plasma jet." Revista Mexicana de Física 65, no. 3 (May 7, 2019): 291. http://dx.doi.org/10.31349/revmexfis.65.291.

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The cathodic arc discharge is a deposition technique widely used to synthesize hard coatings and thin films. The structure of the plasma generated by the electrical discharge and its interaction with neutral particles was studied using numerical simulations. Typical plasma parameters were characterized considering their spatial and temporal dependence, as well as several cathode materials that are commonly used in these systems. For the evolution of the ion density, it was observed the formation of Knudsen layer, and also a dependence of pressure gradients in the global behavior. With respect to the kinetic energy, it was found a deceleration of ions, which is represented by a shock front produced in the plasma−neutrals interaction. On the other hand, the energy releasing was generated due to the heat transference between electrons and ions. The plasma potential follows a behavior, which is similar to that of the ion density, and it is caused by the dynamics of charged particles which is directly affected by the concentration of neutrals and ions. In general, the physical quantities are directly affected by electrical and thermal conductivity of the cathode material. Our results can be applied to understand the plasma phenomena produced in a cathodic arc discharge

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Emelyanov, O., A. Plotnikov, and E. Feklistov. "Positive corona streamer interaction with metalized dielectric: Possible mechanism of cathode destruction." Physics of Plasmas 29, no. 6 (June 2022): 064501. http://dx.doi.org/10.1063/5.0093203.

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This paper examines the effect of pulsed positive point-to-plane corona discharge in millimeter air gaps on the surface of a metalized dielectric. A footprint method was applied to reveal the streamer–surface interaction with Al and Zn thin films (20–50 nm) as a sensitive indicator. A thin metal film-dielectric substrate system was destructed at relatively low typical average currents of 20–50 μA during exposure times of 2–200 s. Destruction occurred in local zones with a size of several μm2 per one discharge pulse, which is substantially lower than the conventional streamer size of several tens of micrometers. An offered model of electro-thermal heating of the cathode layer shows that the dielectric surface temperature can achieve 1000 K and more during the single current pulse of submicrosecond duration. The indicated mechanism is possibly responsible for the effects of the discharge plasma interaction with low heat conductivity cathodes, including biological objects. Intensive heating of the cathode layer should be considered when modeling the streamer–cathode interaction.

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Yamamoto, Kentaro, Manabu Tanaka, Tashiro Shinichi, Kazuhiro Nakata, Keiichi Suzuki, and Kei Yamazaki. "Numerical Modeling of Welding Arc with Complex System between Arc Plasma and Molten Electrode." Materials Science Forum 580-582 (June 2008): 311–14. http://dx.doi.org/10.4028/www.scientific.net/msf.580-582.311.

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It is important to consider the interaction between arc plasma and electrodes because melting of electrodes strongly affects arc plasma. Therefore, a GMA model will be developed, based on the unified model of TIG arc. As a first step, a TIG arc model with a calculation for molten cathode shape has been proposed. This model is calculated in two cases; molten W cathode and Calculation result of W cathode. In the case of W cathode, cathode shape change was found to affect the arc plasma property strongly. Calculated results of radial temperature distributions on electrode surface and arc pressure distributions at the anode surface are very similar to the experimental results.

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Trivedi, K., S. Tanguay, M. Matties, and R. Sacks. "Magnetically Tailored Arc and Glow Discharge Plasmas for Atomic Spectroscopy." Applied Spectroscopy 41, no. 5 (July 1987): 833–43. http://dx.doi.org/10.1366/0003702874448382.

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Three magnetic field-plasma configurations are used to study the interaction of external magnetic fields with analytically useful plasma devices. First, a magnetic field oscillating at 60 Hz and normal to the electric field in a 12-A direct current arc plasma is used to obtain an Ē×B̄ drift motion of the arc current channel. This causes a periodic vertical displacement of the channel. Second, a cw magnetic field is used to alter the structure and radiative properties of a demountable glow discharge lamp that uses a center-post cathode. The magnetic field axis is parallel to the cathode axis, and the lamp is operated in a pseudo-magnetron mode. Third, a damped, oscillatory magnetic field produced by discharging a capacitor through a coil is used to alter the radiative characteristics of several commercial hollow cathode lamps. The magnetic field is parallel to the cathode axis, and again the lamps operate in a pseudo-magnetron mode. In all three systems, the presence of the magnetic field drastically alters the radiative properties of the plasmas.

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Li, Limin, Chao Liu, Xuming Zhang, Guosong Wu, Ming Zhang, Ricky K. Y. Fu, and Paul K. Chu. "Plasma-target surface interaction during non-equilibrium plasma irradiation at atmospheric pressure: Generation of dusty plasma." Laser and Particle Beams 32, no. 1 (November 5, 2013): 69–78. http://dx.doi.org/10.1017/s0263034613000888.

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AbstractThe remaining challenges, developing the relativistic electron beam sources, stimulate the investigations of cathode materials. Carbon-fiber-aluminum composite is the most appropriate cathode materials to construct the robust relativistic electron beam sources. Carbon-fiber-aluminum composite is treated by a non-equilibrium atmospheric plasma torch with a copper electrode based on high-voltage gas discharge. The axial and radial distributions of the plasma torch temperature are measured to determine the optimal treatment temperature and location. Copper-oxide particles with diameters of less than 1 µm are deposited onto the surface of the carbon-fibers and a layer of copper-oxide covers the entire surface as the treatment time is increased. Raman spectroscopy suggests that although the locations of the D and G band are similar, the areas of the D and G bands increase after the plasma treatment due to the reduced graphite crystalline size in the carbon-fibers. Analysis of the copper electrode surface discloses materials ablation arising from the discharge which releases copper from the source. Our results reveal that the atmospheric plasma torch generated by high-voltage discharge is promising in the surface modification of the carbon-fiber-reinforced aluminum composite. Further, the plasma produced by atmospheric plasma torch is dusty plasma, due to the participation of liberated copper particles. The plasma torch was analyzed by fluid dynamics, in terms of plasma density, plasma expansion velocity, and internal pressure, and it was found that the plasma produced by atmospheric torch is supersonic flow.

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Vannaroni, G., C. B. Cosmovici, U. Guidoni, L. Iess, and L. Scandurra. "Interaction of a hollow-cathode source with an ionospheric plasma." Advances in Space Research 10, no. 7 (January 1990): 147–50. http://dx.doi.org/10.1016/0273-1177(90)90289-c.

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Wroński, Z. "Plasma of the cathode zone of glow discharges and its interaction with the cathode surface." Vacuum 63, no. 4 (August 2001): 535–39. http://dx.doi.org/10.1016/s0042-207x(01)00235-4.

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Rakhadilov, B. K., Z. A. Satbayeva, A. E. Kusainov, and E. Naimankumaruly. "Linear plasma device for the study of plasma-surface interactions." Bulletin of Shakarim University. Technical Sciences, no. 3(11) (September 28, 2023): 82–90. http://dx.doi.org/10.53360/2788-7995-2023-3(11)-10.

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In the research and production company "PlasmaScience" (Ust-Kamenogorsk, Kazakhstan) a new laboratory linear plasma installation KAZ-PSI (Kazakstan plasma Generator for Plasma Surface Interactions) for studying the interaction of plasma with material has been developed and built. The article describes some features of the developed experimental setup for the study of surface-plasma interactions. The main elements of the linear plasma setup are an electron-beam gun with a LaB6 cathode, a plasma-beam discharge chamber, an interaction chamber, a target device, and an electromagnetic system consisting of electromagnetic coils. The KAZ-PSI facility allows generating continuous plasma of hydrogen, deuterium, helium, argon and nitrogen. The electron density of the plasma is in the range of the order of 1017 -1018 m-3 and the electron temperature is in the range of 1 to 20 eV. The incident ion energy is controlled by applying a negative bias of up to 2 kV to the target. Experiments on irradiation of tungsten with helium plasma were carried out for the first time at the KAZ-PSI facility. The paper presents the results of studies conducted to study changes in the tungsten mixture. The results have shown that after helium plasma irradiation the morphology of tungsten surface changes and relief is created on the surface due to atomisation of the surface by helium ions, as well as due to the formation of blisters.

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Jassam, H. F., and R. A. Ali. "Interaction of near-cathode plasma layers with thermionic electrodes under high pressure arc plasma." Journal of Physics: Conference Series 2322, no. 1 (August 1, 2022): 012076. http://dx.doi.org/10.1088/1742-6596/2322/1/012076.

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Abstract Theoretical calculations and simulation data were presented to study the effect of the Xe-Dy mixture on properties of arc plasma. The effect of voltage, concentration and temperature on current flow density, power flux density and cathode temperature were studied. Different concentrations of Dysprosium (0.005, 0.01, 0.05, 0.1, and 0.5 mol) were used. The program (NCBL) was used in this work. Results showed a clear effect of concentration on plasma parameters, especially at the highest concentration, in addition to the effect of voltage. We notice that the current density increases from ≥3500k), while (3500 – 5000k) increases for all concentrations due to collisions as well as density of flowing energy For all the concentrations mentioned, we noticed that there is a clear effect of the temperature (≥ 3500k) on current density where increases and from (3500- 5000). we noticed an increase in the current density as well as the voltage especially at (25v) where the current and the energy overflow density increase due to elastic and inelastic collisions because acceleration of electrons with an increase in voltage.

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Ashurbekov, N. A., M. B. Kurbangadzhieva, K. O. Iminov, G. Sh Shakhsinov, and K. M. Rabadanov. "ASYMMETRY OF THE OPTICAL TRANSMISSION SPECTRA OF A PULSED DISCHARGE WITH AN EXTENDED HOLLOW CATHODE DURING AT RESONANCE INTERACTION OF SHORT POLYCHROMATIC LASER PULSES WITH EXCITED NEON ATOMS." Journal of Applied Spectroscopy 89, no. 6 (November 16, 2022): 815–19. http://dx.doi.org/10.47612/0514-7506-2022-89-6-815-819.

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The processes of resonant interaction of short pulses of polychromatic radiation of a dye laser with plasma of a nanosecond discharge in neon with an extended hollow cathode are experimentally studied. During the propagation of laser radiation inside the cathode cavity near the spectral absorption line of Ne I with a wavelength of 650.6 nm, the formation of asymmetric optical transmission spectra of the plasma of the dispersion type are detected, while during the propagation of laser radiation in the region between the electrodes, symmetric transmission spectra of the classical kind are formed.

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R. S. Monzamodeth and B. Campillo. "Study of the Erosion of Copper by Hot Plasma." Journal of Nuclear Physics, Material Sciences, Radiation and Applications 7, no. 2 (February 28, 2020): 173–79. http://dx.doi.org/10.15415/jnp.2020.72022.

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An exhaustive study of the erosion process of a copper cathode exposed to a hot plasma column of 2kJ of energy (T≈0.5-2.0keV) and high electron density (n≈1019-1022cm3) was made, as well as, the radiation field of charged and neutral particles. The characterization of the cumulative damage generated by the plasma/cathode interaction was made by the use of metallographic techniques, scanning electron microscopy (SEM) and by the analysis of mechanical properties. Damage accumulation produced by the impacts of deuterium plasma discharge created in the copper electrode a deep cavity similar to a crater, modifying the morphology of the surface and below it. The microhardness Vickers test was carried out making indentations from the final part of the cavity to cover 1 cm with indentations every 200 μm. Different areas of hardening were observed, the profile suggests a hardening/recovery front and simultaneous recrystallization in the sample, phenomenon associated with the heating/cooling cycles to which the copper cathode is subjected. Images were captured by SEM at different distances from the center of the surface. The region that showed involvement at the macro level corresponds to 2/3 of the radius of the sample from the center to the outside. These phenomena studied are important to understand the nature of the plasma/wall interaction in any fusion device.

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12

Vranchev, A. I., and G. H. Popov. "Model calculation of the cathode double sheath-plasma interaction in low-current thermionic cathode argon discharges." Journal of Physics D: Applied Physics 19, no. 9 (September 14, 1986): 1685–97. http://dx.doi.org/10.1088/0022-3727/19/9/013.

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13

Abbas, Qusay Adnan. "Influence of AL Dust Particles on Air Plasma Characteristics in Cathode Sheath." University of Thi-Qar Journal of Science 4, no. 4 (July 10, 2014): 86–91. http://dx.doi.org/10.32792/utq/utjsci/v4i4.672.

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The gas discharge–dust particle interaction for a dc discharge in air with micron-sized particles is investigated. The work present illustrated the effect of AL dust particle on current and voltage of discharge and on the radial profile of plasma parameters in the cathode sheath in direct current system. The results shows, the present of dust inside the discharge increases the current while the voltage of discharge decreases. Moreover, the radial profile of plasma characteristics that measure by Langmuir probes in the presence of AL dust shows that the dust changes the plasma characteristics and affects the collective processes in such plasma system. The AL dust is charged positively in the cathode sheath and the plasma potential is negative. The presence of dust did not effect on the electron distrabution in that region.

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KINOSHITA, K., T. HOSOKAI, T. OHKUBO, A. MAEKAWA, K. KOBAYASHI, M. UESAKA, and A. ZHIDKOV. "MONO-ENERGETIC ELECTRON GENERATION AND PLASMA DIAGNOSIS EXPERIMENTS IN A LASER PLASMA CATHODE." International Journal of Modern Physics A 22, no. 23 (September 20, 2007): 4310–16. http://dx.doi.org/10.1142/s0217751x07037846.

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Acceleration of plasma electrons by laser wake-filed is the most promising process to produce the next generation of compact accelerators because of its ultrahigh acceleration gradient. To achieve the efficient and stable mono-energetic acceleration of plasma electrons, we investigated the laser-plasma interaction and its correlation to electron acceleration through single shot measurements. We observed a thin laser channel when a mono-energetic spectrum was generated.

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Cirillo, D., Emilio del Giudice, Roberto Germano, S. Sivasubrammanian, Yogendra N. Srivastava, V. Tontodonato, G. Vitiello, and Allan Widom. "Water Plasma Modes and Nuclear Transmutations on the Metallic Cathode of a Plasma Discharge Electrolytic Cell." Key Engineering Materials 495 (November 2011): 124–28. http://dx.doi.org/10.4028/www.scientific.net/kem.495.124.

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In the conceptual framework of Quantum ElectroDynamics (QED) it has been proventhat liquid water is made up of two phases : 1) a coherent phase where the electron cloud of watermolecules oscillates in phase with a trapped electromagnetic field within extended regions, calledCoherence Domains (CD); 2) a non coherent phase formed by a gas-like ensemble of molecules fillingthe interstices among the CD's. The constituentmolecules of the coherent phase oscillate between theirindividual ground state and an excited state where one electron is so loosely bound to be consideredquasi-free. Therefore the coherent phase contains a plasma of quasi-free electrons. In the bulk water,as in the case of superfluid liquid Helium, each molecule crosses over continuously between the twophases. On the contrary, close to the surface of a metallic cathode in a chemical cell , the attractionbetween molecules and wall stabilizes the coherent phases so that the layer of interfacial water ismainly coherent and capable of holding a negative electronic charge. When the chemical cell voltageexceeds a threshold, an i! nterfacial water- cathode metal surface plasma mode is developed. Fromthe collective energies continuously pumped into the plasma, the weak interaction e + p+ → n + νemay be induced which produces neutrons and neutrinos from Hydrogen atoms. The neutrons may thenultimately induce other nuclear transmutations on the cathode metal surface.

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Stancu, Cristian, Valentina Marascu, Anca Bonciu, Adrian Bercea, Silviu Daniel Stoica, and Catalin Constantin. "Tungsten Material Behavior under H2, D2, and He Plasma Interaction Conditions in the Framework of Fusion-Relevant Studies." Materials 16, no. 21 (October 25, 2023): 6853. http://dx.doi.org/10.3390/ma16216853.

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In the current study, bulk tungsten material surfaces are exposed to hydrogen, deuterium, and helium plasmas in the radiofrequency domain (13.56 MHz) at an input power of 250 W using the hollow-cathode configuration. The ejected material is collected on titanium substrates at various distances (from 6 mm up to 40 mm). Therefore, the exposed tungsten materials are investigated for surface changes (blister occurrence, dust formation, or nano-structuration), along with the crystallinity, depending on the plasma’s exposure times (from 30 min up to 120 min for each plasma type). Also, the collected materials are analyzed (morphological, structural, and statistical investigations) for dust and dust film-like appearance. Plasma discharges are analyzed using two methods: optical emission spectroscopy, and single Langmuir probes, to emphasize the nature of the used plasmas (cold discharges, ~2 eV), along with the presence of tungsten emission (e.g., WI 406.31 nm, WI 421.31 nm) during the plasma lifetime. By using a dedicated protocol, a method was established for obtaining fusion-relevant tungsten surfaces in the hydrogen and deuterium plasma discharges. By using the implemented method, the current paper introduces the possibility of obtaining a new tungsten morphology, i.e., the dandelion-like shape, by using helium plasma, in which the W18O49 compound can be found.

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Blanchard, Pierre-Yves, Alice Parnière, Nicolas Donzel, Sara Cavaliere, Jacques Rozière, and Deborah J. Jones. "Functionalisation of Carbon Catalyst Support By Plasma Treatment for PEMFC Cathode." ECS Meeting Abstracts MA2024-01, no. 36 (August 9, 2024): 2017. http://dx.doi.org/10.1149/ma2024-01362017mtgabs.

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Proton exchange membrane fuel cell (PEMFC) is one promising electric device to replace the combustion engine using fossil fuel especially for heavy-duty transport. One of the main issue for the widespread of this technology on the European roads is the cost and degradation of their components over time. The sluggish reduction of dioxygen at the cathode require high amount of noble metal (i.e. platinum). Under PEMFC operating conditions, carbon as catalyst support is unstable. This study presents a new approach to improve the stability of the cathode components (catalyst, carbon support and ionomer) thanks to the enhancement of the interaction between the three entities and to reduce carbon corrosion. Plasma treatment were performed on different carbon black sources (different surface area and porosity) to functionalize their surface by nitrogen function using different gas. The modified carbons were characterized by TEM, XPS, Raman spectroscopy, calorimetry, elemental analysis. The plasma treatments were reproducible and allow controlling the degree of functionalisation. The nitrogen doped carbons were catalysed by platinum nanoparticles. A better dispersion of the nanoparticles was observed by TEM showing the interest of the plasma treatment. Cyclic voltammetry were performed and a better catalytic activity toward the electrochemical reduction of O2 was observed.[1] Isothermal titration calorimetry experiments were carried out and show an improved interaction between the nitrogen functionalized carbon and the ionomer. [1] A. Parnière, P.-Y. Blanchard, S. Cavaliere, N. Donzel, B. Prelot, J. Rozière, D.J. Jones, Nitrogen Plasma Modified Carbons for PEMFC with Increased Interaction with Catalyst and Ionomer, J. Electrochem. Soc. 169 (2022) 044502. Figure 1

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Obukhov, V. A., and M. V. Cherkasova. "Interaction between plasma and the channel surface in a multichannel hollow cathode." Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques 8, no. 3 (May 2014): 581–87. http://dx.doi.org/10.1134/s1027451014030331.

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Marascu, Valentina, Cristian Stancu, Tomy Acsente, Anca Bonciu, Catalin Constantin, and Gheorghe Dinescu. "Low-Temperature H2/D2 Plasma–W Material Interaction and W Dust Production for Fusion-Related Studies." Coatings 13, no. 3 (February 24, 2023): 503. http://dx.doi.org/10.3390/coatings13030503.

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In this paper, results concerning hydrogen and deuterium plasma (RF, 13.56 MHz) interactions with tungsten surfaces, were reported. We used the Hollow-Cathode (HC) configuration for plasma–tungsten surface interaction experiments, along with the collection of tungsten dust, at different distances. Further on, the plasma-exposed tungsten surfaces and the collected dust were morphologically analyzed by contact profilometry, scanning electron microscopy, and energy dispersive spectroscopy measurements, along with chemical investigations by the X-ray photoelectron spectroscopy technique. The results showed that exposing the tungsten surfaces to the hydrogen plasma induces surface erosion phenomena along with the formation of dust and interconnected W structures. Herein, the mean ejected material volume was ~1.1 × 105 µm3. Deuterium plasma facilitated the formation of blisters at the surface level. For this case, the mean ejected material volume was ~3.3 × 104 µm3. For both plasma types, tungsten dust within nano- and micrometer sizes could be collected. The current study offers a perspective of lab-scaled plasma systems, which are capable of producing tungsten fusion-like surfaces and dust.

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Емельянов, О. А., А. П. Плотников, and Е. Г. Феклистов. "Воздействие импульсного тлеющего разряда атмосферного давления на алюминиевые пленки нанометровой толщины." Письма в журнал технической физики 47, no. 6 (2021): 19. http://dx.doi.org/10.21883/pjtf.2021.06.50752.18539.

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The effect of a positive pulsed corona discharge on the thin-film cathode surface was studied in atmospheric pressure air gaps of 2–8 mm at voltages of 5–15 kV. Observed current pulses had the following parameters: repetition rate about 10-15 kHz, pulse duration of 300-500 ns, and amplitude of 10-20 mA. It was shown that at relatively low average currents of 20–50 μA, the discharge transforms into the glow one near the cathode. Due to the discharge channel radial contraction to micrometer scale, Joule heating of the formed cathode layer can lead to a temperature increase up to 1000 K and cause local erosion of the cathode surface. This mechanism should be taken into account when analyzing the interaction of discharge plasma with biological objects.

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Galaly, Ahmed Rida, and Nagia Dawood. "Theoretical and Experimental Study of the Effect of Plasma Characteristics on the Mechanical Properties of Ihram Cotton Fabric." Membranes 12, no. 9 (September 12, 2022): 879. http://dx.doi.org/10.3390/membranes12090879.

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Theoretical and experimental investigations of the radial distribution function of the electron temperature (RDFT), for the abnormal glow region in a low-density plasma fluid and weakly ionized argon gas, are provided. The final proved equation of RDFT agrees with the experimental data for different low pressures ranging from 0.2 to 1.2 torr, confirming that the electron temperatures decrease with an increasing product of radial distance (R) and gas pressures (P). A comparison of the two configurations: R>L and L>R, for the axial distance (L), from the tip of the single probe to the cathode electrode, and the cathode electrode radius (R), shows that, in both cases, the generated plasma temperatures decrease, and densities increase. The RDFT accurately depicts a dramatic decrease for L < R by 60% compared with the values for L > R. This indicates that, when L < R, the rate of plasma loss by diffusion is reduced. Under this investigation, the mechanical characteristics of treated and pre-treated Ihram Cotton Fabric Samples were compared under the Influence of the different two configurations of Plasma Cell discharge: R>L>R. These characteristics included resiliency, strain hardening, tensile strength, elongation percentage, yield strength, ultimate tensile strength, toughness, and fracture (breaking) point. Furthermore, the mechanism parameters of plasma interaction with textile membrane will be discussed, such as: process mechanism, interaction, and gas type.

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Rakhadilov, Bauyrzhan, Zarina Satbayeva, Arystanbek Kusainov, Erasyl Naimankumaruly, Riza Abylkalykova, and Laila Sulyubayeva. "Linear Plasma Device for the Study of Plasma–Surface Interactions." Applied Sciences 13, no. 21 (October 25, 2023): 11673. http://dx.doi.org/10.3390/app132111673.

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At the research and production company “PlasmaScience” (Ust-Kamenogorsk, Kazakhstan), a linear plasma generator installation, KAZ-PSI (Kazakhstan Plasma Generator for Plasma Surface Interactions), has been developed and constructed for the study of the interaction of plasma and materials. This article outlines some features of the developed experimental installation designed for the investigation of surface–plasma interactions. The primary components of the linear plasma installation include an electron-beam gun with a LaB6 cathode, a plasma-beam discharge chamber, an interaction chamber, a target device, and an electromagnetic system comprising electromagnetic coils. The KAZ-PSI unit enables continuous plasma generation using hydrogen, deuterium, helium, argon, and nitrogen. The electron density of the plasma is in the range of about 1017–1018 m−3 and the electron temperature is in the range of 1 to 20 eV. The incident ion energy is regulated by applying a negative potential of up to 2 kV to the target. Experiments on the irradiation of tungsten with helium plasma were carried out using the KAZ-PSI installation for the first time. This article presents the research findings on the structure and properties of tungsten relative to the temperature of helium plasma irradiation. Alterations in roughness, microstructure, hardness, modulus of elasticity, and erosion of the tungsten’s surface following helium plasma irradiation at varying temperatures were examined. The study’s results indicate that helium plasma irradiation induces changes in the morphology of the tungsten’s surface, creating surface relief due to sputtering by helium ions, as well as the formation of blisters. Mechanical testing revealed that after irradiation at T = 500 °C, there was an increase in hardness of up to 10%, and a slight decrease in modulus of elasticity. And after irradiation at T = 900 °C and T = 1300 °C, both hardness and elastic modulus decreased with rising temperature. The tungsten surface erosion evaluation results showed that the degrees of surface erosion increase with increasing target temperature.

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Vannaroni, G., M. Dobrowolny, E. Melchioni, F. De Venuto, and R. Giovi. "Characterization of the interaction between a hollow cathode source and an ambient plasma." Journal of Applied Physics 71, no. 10 (May 15, 1992): 4709–17. http://dx.doi.org/10.1063/1.350661.

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Eggs, C., H. Kersten, H. E. Wagner, and H. Wulff. "Plasma wall interaction for TiNx film deposition in a hollow cathode arc discharge." Thin Solid Films 290-291 (December 1996): 381–85. http://dx.doi.org/10.1016/s0040-6090(96)09125-0.

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Breus, A., S. Abashin, and O. Serdiuk. "Carbon nanostructure growth: new application of magnetron discharge." Journal of Achievements in Materials and Manufacturing Engineering 109, no. 1 (November 1, 2021): 17–25. http://dx.doi.org/10.5604/01.3001.0015.5856.

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Purpose: The application of a common magnetron discharge to the growth of carbon nanostructures is studied. The simplicity of the proposed technique can be beneficial for the development of new plasma reactors for large-scale production of carbon nanostructures. Design/methodology/approach: Graphite cathode was treated by carbon-containing powder accelerated by use of nozzle, and then aged in hydrogen. Superposition of glow and arc discharges was obtained, when putting the cathode under the negative biasing with respect to the walls of a vacuum chamber. The pulsed discharge was preserved through the whole time of treatment. This process was explained in terms of interaction of glow discharge plasma with a surface of the cathode made of non-melting material. Findings: The plasma treatment resulted in generation of the diverse nanostructures confirmed by SEM and TEM images. Spruce-like nanostructures and nanofibers are observed near the cathode edge where the plasma was less dense; a grass-like structure was grown in the area of “race-track”; net-like nanostructures are found among the nanofibers. These findings allow concluding about the possible implementation of the proposed method in industry. Research limitations/implications: The main limitation is conditioned by an explosive nature of nanostructure generation in arcs; thus, more elaborate design of the setup should be developed in order to collect the nanospecies in the following study. Practical implications: High-productivity plasma process of nanosynthesis was confirmed in this research. It can be used for possible manufacturing of field emitters, gas sensors, and supercapacitors. Originality/value: Synthesis of carbon nanostructures is conducted by use of a simple and well-known technique of magnetron sputtering deposition where a preliminary surface treatment is added to expand the production yield and diversity of the obtained nanostructures.

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Bobrov, M. S., M. Y. Hrebtov, and P. V. Yudin. "Numerical simulation of domain wall motion in a surface discharge over a ferroelectric." Journal of Physics: Conference Series 2119, no. 1 (December 1, 2021): 012124. http://dx.doi.org/10.1088/1742-6596/2119/1/012124.

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Abstract The article presents a simplified numerical simulation of a vacuum ferroelectric cathode operating in a low-current mode (without surface plasma formation). The field emission from the cathode was simulated for the range of applied electric field magnitudes. The polarization domain growth process during the charging of ferroelectric surface was simulated using Landau-Ginzburg-Devonshire model. Interaction of the electrons with a depolarization field of a domain wall led to an attraction of the electrons to the polarization domain boundaries. A close to the linear dependence of the equilibrium domain wall position from the applied electric field was found with the total emitted charge proportional to the domain size.

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Liu, Shuai, Tao Xu, Yuhao Shi, Wei Zhan, Chengying Liu, Zhijian Lu, and Lanjun Yang. "Development of a repetitive plasma source for simulation of mitigated edge localized mode transient heat load." Review of Scientific Instruments 93, no. 10 (October 1, 2022): 103544. http://dx.doi.org/10.1063/5.0106603.

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A repetitive plasma source for simulation of mitigated edge localized mode transient heat load is developed. The repetitive plasma source consists of a repetitive pulsed power supply and a pulsed plasma accelerator. The pulsed plasma accelerator is composed of a coaxial cathode, an anode, and an insulator. The inner electrode is the cathode with a diameter of 5 mm, and the outer electrode is the anode with a diameter of 15 mm. An angular magnetic field is generated by the discharge current and acts with the radial current to generate Lorentz force, which drives the plasma ejecting to the outlet. The repetitive pulsed power supply can be divided into three parts, the primary charge circuit, the resonant charge circuit, and the discharge circuit. The time interval between resonant charge and discharge is 4 ms. The repetitive discharge components include ten modules running in parallel. There are four working modes for discharge components, depending on the number of simultaneously discharged modules. For Mode A, the maximum repetitive frequency is 50 Hz, and the transient heat load is 0.06 MJ/m2 when the discharge current is 10.5 kA. For Mode D, the maximum repetitive frequency is 5 Hz, and the transient heat load is 0.45 MJ/m2 when the discharge current is 66 kA. This is of great significance for the study of the interaction between plasma and plasma-facing materials in tokamak.

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Mesyats, G. A., and S. A. Barengol’ts. "Interaction of plasma jets and droplets in the cathode region of a vacuum arc." Journal of Experimental and Theoretical Physics Letters 75, no. 6 (March 2002): 257–58. http://dx.doi.org/10.1134/1.1481458.

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Kochergin, V. K., R. A. Manzhos, N. S. Komarova, A. S. Kotkin, A. G. Krivenko, I. N. Krushinskaya, and A. A. Pelmenyov. "Features of the Synthesis of Few-Layer Phosphorene Structures During Plasma Electrochemical Cleavage of Black Phosphorus." Himiâ vysokih ènergij 58, no. 3 (October 25, 2024): 216–20. http://dx.doi.org/10.31857/s0023119324030069.

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A comparative study of the emission spectra of cathode electrolysis plasma during plasma electrochemical cleavage of black phosphorus and graphite under maximally identical experimental conditions has been carried out. A significantly lower concentration of active intermediates (OH radicals and O atoms) in the electrolysis plasma during the cleavafe of black phosphorus was found compared with a graphite electrode. It is assumed that this effect is due to a significantly higher rate of interaction of these intermediates with synthesized phosphorene structures than with graphene-like particles. This is confirmed by the detection of a much higher oxygen content in the products of black phosphorus cleavage than in synthesized carbon nanoparticles.

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Lateef, Syed Abdul, A. T. Sriram, M. Murali Krishnan, and A. Sivathanu Pillai. "Design of Magnetic Circuit for Stationary Plasma Thruster." Journal of Physics: Conference Series 2070, no. 1 (November 1, 2021): 012032. http://dx.doi.org/10.1088/1742-6596/2070/1/012032.

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Abstract SPT-100 electrostatic thruster is considered, and the effects of magnetic circuit is studied by introducing magnetic screen. The magnetic flux density in the discharge channel is generated with the help of one inner coil and four outer coils. The radial magnetic field has to be maximum near the exit plane of the thruster to trap the electrons in acceleration region which are emitted from an external hollow cathode. These electrons help in increasing the ionization rate of the propellant gas. This is obtained by placing magnetic poles near exit plane. It helps to traps the electrons emitted from the external hollow cathode. The magnetic circuit should be designed such that the magnetic flux density is near to zero at the anode plane to reduce interaction of electrons with channel walls. To arrive at such better design, magnetic screens are used. Computational simulations are performed to quantify the magnetic flux density distribution along the channel using COMSOL Multiphysics software. The simulation results show that the obtained radial magnetic flux density is maximum near the exit plane, and the magnetic screens help in reducing the magnetic field at the anode region while maintaining the maximum magnetic field at the exit plane.

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Lu, Shuai, Xiaowei Sun, Bowei Zhang, and Junsheng Wu. "Review of Cathode Plasma Electrolysis Treatment: Progress, Applications, and Advancements in Metal Coating Preparation." Materials 17, no. 16 (August 7, 2024): 3929. http://dx.doi.org/10.3390/ma17163929.

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Cathodic plasma electrolytic treatment (CPET) is an emerging surface modification and coating preparation technology. By utilizing plasma discharge induced through electrolysis and the cooling impact of electrolyte, metal cleaning, saturation, and coating preparation are efficiently achieved. In this review, the principle, application, and development of the CPET process are briefly summarized based on the past literature. Detailed insights are provided into the influence of electrolyte parameters (pH, metal salt concentration, and temperature), electrical parameters (voltage, duty cycle, and frequency), and process parameters (electrode area ratio, material, roughness, and deposition time) on plasma discharge and coating formation for metal coatings. The interaction mechanism between plasma and material surfaces is also investigated. Recommendations and future research avenues are suggested to propel CPET and its practical implementations. This review is expected to provide assistance and inspiration for researchers engaged in CPET.

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ZAKAULLAH, M., IJAZ AKHTAR, S. F. MEHMOOD, A. WAHEED, and G. MURTAZA. "A COST EFFECTIVE X-RAY DETECTOR FOR PLASMA FOCUS DIAGNOSTICS." Modern Physics Letters B 14, no. 15 (June 30, 2000): 563–70. http://dx.doi.org/10.1142/s0217984900000732.

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A time-resolved rugged X-ray detector (XRD) which may be used in intense radiation environment is developed. The detector is used to study the X-ray emission from a low-energy (2.3 kJ) Mather-type plasma focus energized by a 32 μF single capacitor, using hydrogen and argon (3:2) mixture as gas filling. In the detector, the electron emitter is made of nickel and aluminum. The sensitivity of the detector with nickel cathode is found to be very low. No signal could be recorded by masking the detector with even the 2 μm thick Al foil. When Al cathode is used in the XRD, the sensitivity of the detector increases abruptly. To stop the optical/ultraviolet radiation from approaching the active area, it is masked with 6 μm Al filter. It is found that an XRD with nickel cathode is not useful for X-ray detection in a low-energy plasma focus. However, due to its excellent response to vacuum ultraviolet radiation (≤600 Å), it may find application in the study of the axial rundown of current sheath, and its velocity. The X-ray emission from focus plasma is the highest at 0.5 mbar. With increase in pressure, the emission is dropped. At filling pressures of 2.0–2.5 mbar, the X-ray emission increases again. High X-ray emission at 0.5 mbar is due to interaction of energetic electrons in the current sheath with the anode surface, whereas moderately high emission at 2.0–2.5 mbar is caused by an axially moving shockwave.

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Matsuda, Y., Y. Yamori, S. Ohgushi, M. Muta, and H. Fujiyama. "Plasma cathode—surface interaction in reactive magnetron sputtering for indium—tin-oxide thin film deposition." Surface and Coatings Technology 98, no. 1-3 (January 1998): 1286–92. http://dx.doi.org/10.1016/s0257-8972(97)00246-6.

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Kozelkov, Serhii, Oleksandr Shulha, Oleksandr Shefer, and Dmytro Neliuba. "Further development of satellite telecommunications radio signals noise immunity increasing method." International Journal of Engineering & Technology 7, no. 4.8 (October 13, 2018): 17–21. http://dx.doi.org/10.14419/ijet.v7i4.8.27207.

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The problem of radio communication loss during spacecraft passage at hyperspeed through dense layers of atmosphere at heights of 60-120 km as result of plasma ionization shock wave formation is analyzed. As a result, this part of spacecraft trajectory is the most problematic from navigation and control point of view. A part of this unsolved problem is identified and an innovative method for solving it is proposed â€“ a method of resonant radio signal regeneration developed, which based on interaction of outer ionized layer elementary particles with artificially generated high intensity negative radiation. Technical means for artificial low-temperature plasma energy-efficient formation have been developed. A design for equipotential low-temperature plasma of high intensity, which based on near-cathode region glow discharge and depends on electrodes geometric parameters and gaseous medium physical parameters proposed. This method, in comparison with existing spacecraft radio communication methods, does not introduce changes into spacecraft external design and does not affect flight aerodynamics. High-temperature plasma shell with artificial intense negative radiation interaction simulation confirms the formation of resonant regenerative transport layer that facilitates radio signal passage through plasma ionization shock wave around spacecraft.Â Â

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Li, Jing, Qiu Ting Yu, Yun Dong Cao, Xiao Ming Liu, and Chong Xu. "A Microscopic Study of Before-Arc Process in Metal Vapor Plasmas Proximal Cathode Region. Part I Formation of the Proximal Cathode Region." Applied Mechanics and Materials 325-326 (June 2013): 1339–42. http://dx.doi.org/10.4028/www.scientific.net/amm.325-326.1339.

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Metal vapor arc in vacuum breaker is a very complex phenomena and the researches on the process of arc creating are the effective method to improve breaking ability. By the theoretical study and numerical simulation, exploring the formation of plasma sheath near the cathode, charged particles energy distribution and influence elements in before-arc process are the fundamentals of this paper. Before-arc process is the fundermental of arc energy and the proximal cathode region is the important area for vacuum arc forming, so before-arc process of metal vapor arc was simulated here. The modification to electron motion produced by the interaction between charged particles and plane electrodes and both elastic and charge exchange collisions between electrons and neutral gases were considered here. The copper cross section adopted here was related to the particle energy. The tracks of electrons were traced until they reached to the anode surface. Based on this method, the formation of proximal cathode region and some microscopic parameters were simulated here. The results show that the collision between charged particles with the electrodes is the necessary condition in proximal cathode regions formation.

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Breus, Andrii, Oleksii Serdiuk, Vasyl Ruzaikin, and Oleg Baranov. "DISCHARGE CHARACTERISTICS OF THE MAGNETRON SYSTEM FOR SPUTTERING, DEPOSITION, AND NANOTECHNOLOGY APPLICATIONS." Aerospace technic and technology, no. 6 (November 27, 2020): 72–79. http://dx.doi.org/10.32620/aktt.2020.6.08.

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Magnetron sputtering is known for years as a powerful tool for coating deposition of cutting tools and machine parts. However the experimental measurements of the magnetron discharge parameters are still necessary to provide a consumer of the magnetron system with the reliable characteristics. A voltage-current relation is the most applied characteristic of the discharge, and it is described as the power low of a type U = U0 + aIn, where U and I are the voltage drop and the discharge current, respectively, and U0 and n are constant. First part of the research is dedicated to the experiments conducted in the magnetron setup provided with the titanium cathode in a vacuum chamber filled with argon or argon-nitrogen mixture, and the constants are determined for the particular geometry of the magnetron sputtering system. The obtained results can be used to choose the operation modes for the traditional applications of the magnetron discharge such as ion cleaning and heating of the non-magnetic workpieces arranged on the cathode, as well as for the sputtering deposition of the titanium and titanium nitride coatings on the surfaces of the workpieces located above the magnetron cathode. In the next part of the research the novel application of the magnetron for production of carbon nanostructures is considered. For the purpose, a layer of expanded graphite is arranged on the magnetron cathode, and the discharge is initiated in oxygen atmosphere. It was found that for the time interval of a few hours the discharge is described as a superposition of the typical magnetron glow with arc spot generation, and the intensity of the arcs is not decreased with time. At that, the arc initiation was accompanied with the formation of clusters of the graphite cathode. The process is explained in terms of the cathode spot generation at the interaction of the arc plasma with the non-melting material. This process can be beneficial for the development of the plasma reactors for the large-scale production of the carbon species at the low gas pressures suitable for the magnetron discharge operation. Thus, the magnetron sputtering systems provided with the expanded graphite cathode can be considered as the tool to grow carbon nanospecies in the arc discharge cathode spots.

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37

Anshakov, A. S., A. V. Cherednichenko, M. V. Cherednichenko, and V. A. Serikov. "Mathematical model of the interaction of plasma with the inner surface of a hollow cathode in a vacuum plasma torch." Journal of Physics: Conference Series 1661 (November 2020): 012019. http://dx.doi.org/10.1088/1742-6596/1661/1/012019.

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38

Fuster, Lucas, Gerjan Hagelaar, Romain Pascaud, Antoine Simon, Patrick Hoffmann, Laurent Liard, Olivier Pascal, and Thierry Callegari. "Plasma-based microwave power limitation in a printed transmission line: a self-consistent model compared with experimental data." Plasma Sources Science and Technology 31, no. 2 (February 1, 2022): 025009. http://dx.doi.org/10.1088/1361-6595/ac4848.

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Abstract Plasma-based microwave power limitation in a suspended microstrip transmission line integrating a micro hollow cathode discharge (MHCD) in its centre is experimentally and numerically studied. Transient and steady state microwave power measurements exhibit a limitation threshold of 28 dBm and time responses of 25 microseconds. Intensified charge-coupled device imaging shows that microwave breakdown occurs at the top of the MHCD. The plasma then extends towards the microwave source within the suspended microstrip transmission line. Besides, a self-consistent model is proposed to simulate the non-linear interaction between microwave and plasma. It gives numerical results in agreement with the measurements, and show that the plasma expansion during the transient response is related to a shift between the ionization source term and the electron density maximum. The propagation speed, under the tested conditions, depends mainly on the stepwise ionization from the excited states.

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Cao, Zhiyuan, Rui Li, Bo Cao, Wenlong Yan, Liqiong Sun, Jianhua Wang, Yingsan Geng, and Zhenxing Wang. "Hybrid plasma modeling of the interaction between the vacuum arc jet and the hot metallic particle near the current zero." Physics of Plasmas 29, no. 11 (November 2022): 113512. http://dx.doi.org/10.1063/5.0107444.

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In this paper, the interaction between the vacuum arc plasma jet and the hot metallic particle near current zero was investigated by numerical simulation. A vacuum arc plasma jet model was developed using the hybrid simulation method, in which electrons were considered as a massless fluid, while heavy particles such as atoms and ions were modeled as particles. In this model, the effect of the evaporation of metal atoms from the metallic particle was considered. Additionally, the Monte Carlo collision method was used to model inelastic collisions between electrons and heavy particles. The simulation results demonstrate that the metallic particle blocks the plasma jet, causing an asymmetric and nonuniform distribution in the plasma jet. Furthermore, some of the evaporated atoms from the hot metallic particle are converted into Cu1+ ions by ionization collisions with electrons. The drift velocity of Cu1+ ions coming from the ionization of metal vapor is much lower than that of highly energetic ions emitted from the cathode spot, making it difficult for them to be completely dissipated as soon as possible during the extinguishing phase. Moreover, the presence of a hot metallic particle causes an increase in the density of plasma in its surroundings, which increases the probability of arc reignition in the post-arc phase.

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40

Sulyubayeva, L. G., B. K. Rakhadilov, Y. Naimankumaruly, M. B. Bayandinova, N. Muktanova, and N. E. Berdimuratov. "Study of changes in the surface structure of tungsten irradiated by helium plasma." Bulletin of the Karaganda University "Physics Series" 113, no. 1 (March 17, 2024): 23–33. http://dx.doi.org/10.31489/2024ph1/23-33.

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One of the important aspects is the interaction of plasma with the surface of a material, especially in the conditions of a fusion facility. The current work presents the preliminary results of the study of tungsten surface structure modification under helium plasma irradiation. A small-sized linear simulator KAZ-PSI with a plasma-beam setup was designed and assembled, where helium was used as a working gas. The main elements of the linear plasma simulator are an electron beam gun with a LaB6 cathode, a plasma-beam discharge chamber, an interaction chamber, a target device, and an electromagnetic system consisting of electromagnetic coils. It was revealed that under irradiation on the surface of the samples there is a relief with defective structure consisting of chaotically arranged ledges and pits of various shapes with average size (100‒600) nm and pore sizes (0.1‒1.5) μm with visible areas of flaking and sputtering. It was found that when the negative potential on the target is varied by –500V/–1000V/–1500V, the formation of dislocation with chaotic and cellular structure of tungsten with an average grain size of (1‒25) μm is observed; it was revealed that the total values of elastic and plastic components of deformation across the tungsten grain differ from each other by about 2.5 times.

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41

McNally, Dylan P., Wei Zhang, and Chunmei Ban. "Plasma Enabled Lithophilic Host for Lithium Anodes." ECS Meeting Abstracts MA2022-01, no. 2 (July 7, 2022): 407. http://dx.doi.org/10.1149/ma2022-012407mtgabs.

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The surge in electric vehicles and portable electronics has sparked increased demand for high-energy-density, rechargeable batteries. Lithium (Li) metal is sought after as the highest energy density anodes. However, Li metal suffers from many challenges including dendritic growth during stripping and plating and safety issues. This talk aims to discuss strategies to mitigate dendritic growth by using a 3D carbon-based host, as well as scalable fabrication techniques to integrate Li metal into a desirable 3D matrix. Electron microscopy and X-ray photoelectron spectrometers are combined to investigate the surface chemistry and morphology, in order to better understand the interaction between the Li metal and 3D carbon-based host material. Identified shifts in the C1s and O1s peaks demonstrate added surface functional groups in the carbon-based host material. With surface functionalization, the proposed Li-metal anode demonstrates significantly improved stability of stripping and plating when compared with lithium metal foil. As a result, the cells assembled with our proposed Li metal anode and the LiNixMnyCozO2 (x+y+z=1) cathode displays enhanced cycling reversibility as compared to the cells assembled with the Li metal foil.

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Filatov, R. A., and A. E. Hramov. "Simulation of oscillatory processes in a beam-plasma system with a virtual cathode in gas-filled interaction space." Plasma Physics Reports 37, no. 5 (May 2011): 395–408. http://dx.doi.org/10.1134/s1063780x11040040.

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43

Xiao, Lei, Ding Fan, and Jiankang Huang. "Tungsten cathode-arc plasma-weld pool interaction in the magnetically rotated or deflected gas tungsten arc welding configuration." Journal of Manufacturing Processes 32 (April 2018): 127–37. http://dx.doi.org/10.1016/j.jmapro.2018.01.026.

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Lewis, Cris, Stephen K. Doorn, David M. Wayne, Fred L. King, and Vahid Majidi. "Characterization of a Pulsed Glow Discharge Laser Ablation System Using Optical Emission." Applied Spectroscopy 54, no. 8 (August 2000): 1236–44. http://dx.doi.org/10.1366/0003702001950823.

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Investigations involving laser-based sampling of copper into an auxiliary pulsed glow discharge for ionization and excitation are presented. The interaction of the ablated copper with the auxiliary glow discharge was studied by monitoring the copper atom emission signal at 368.744 nm. Results demonstrate the ability to time ablation appropriately to access specific temporal regions of the pulsed plasma. More specifically, laser-ablated material was introduced into the glow discharge negative glow during the afterpeak. Ionization and excitation was accomplished by collisions with a metastable argon population produced by the glow discharge (Penning ionization) followed by recombination to yield excited-state Cu atoms. The work presented investigates parameters that affect the atomic emission signal intensity of the ablated material, including cathode-to-target distance, discharge gas pressure, and relative timing of discharge and ablation. Results demonstrate that decreasing the glow discharge working gas pressure increases the transport efficiency of laser-ablated material into the negative glow. These investigations are part of an ongoing series of studies on sample introduction schemes that utilize different ionization and excitation mechanisms found in pulsed glow discharge plasmas.

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Borisovskiy, P. A., G. V. Kiselev, L. I. Kiseleva, E. N. Moos, and A. V. Naumkin. "Changes in the structure and composition of the surface of a cathode upon long-term interaction with helium‒neon plasma." Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques 11, no. 3 (May 2017): 554–56. http://dx.doi.org/10.1134/s102745101703003x.

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46

Auluck, S. K. H., R. Verma, and R. S. Rawat. "Evaluation of a New Kind of Z-Pinch-Based Space Propulsion Engine: Theoretical Foundations and Design of a Proof-of-Concept Experiment." Plasma 7, no. 4 (December 19, 2024): 939–77. https://doi.org/10.3390/plasma7040052.

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This paper explores a recently proposed scalable z-pinch-based space propulsion engine in greater detail. This concept involves a “modified plasma focus with a tapered anode that transports current from a pulsed power source to a consumable portion of the anode in the form of a hypodermic needle tube continuously extruded along the axis of the device”. This tube is filled with a gas at a high pressure and also optionally with an axial magnetic field. The current enters the metal tube through its contact with the anode and returns to the cathode via the plasma sliding over its outer wall. The resulting rapid electrical explosion of the metal tube partially transfers current to a snowplough shock in the fill gas. Both the metal plasma and the fill gas form axisymmetric converging shells. Their interaction forms a hot and dense plasma of the fill gas surrounded by the metal plasma. Its ejection along the axis provides the impulse needed for propulsion. In a nonnuclear version, the fill gas could be xenon or hydrogen. Its unique energy density scaling could potentially lead to a neutron-deficient nuclear fusion drive based on the proton-boron avalanche fusion reaction by lining the tube with solid decaborane. In order to explore the inherent potential of this idea as a scalable space propulsion engine, this paper discusses its theoretical foundations and outlines the first iteration of a conceptual engineering design study for a proof-of-concept experiment based on the UNU-ICTP Plasma Focus facility at the Nanyang Technological University, Singapore.

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Олешко, В. И., В. Ф. Тарасенко, А. Г. Бураченко, and V. V. Nguyen. "Филаментация и самофокусировка электронных пучков в вакуумных и газовых диодах." Письма в журнал технической физики 45, no. 7 (2019): 3. http://dx.doi.org/10.21883/pjtf.2019.07.47526.17640.

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AbstractIn this paper, we experimentally studied pulsed electron beams with a high local density. The conditions in which the energy density cumulation is observed during the interaction of electrons with the anode are shown to develop in vacuum and gas diodes at nanosecond and subnanosecond durations of a beam current pulse and a decrease in the interelectrode gap. The average electron energy in filamentation and self-focusing of an electron beam in a vacuum diode of an accelerator at a current of ~2 kA and a no-load voltage of ~400 kV was established to be 50–100 keV while the energy density was 10^9–10^10 J/cm^3. It is confirmed that the beam current density in a gas diode can exceed 1 kA/cm^2. It is hypothesized that superdense electron beams in vacuum and gas diodes are formed as a result of avalanche multiplication of runaway electrons in the cathode–anode gap plasma.

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Darakov, D. S., V. I. Vishnyakov, A. A. A. Ennan, and S. A. Kiro. "Fume emissions by electric arc during gas metal arc welding." Physics of Aerodisperse Systems, no. 60 (December 15, 2022): 120–42. http://dx.doi.org/10.18524/0367-1631.2022.60.267071.

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The influence of welding arc regime on the welding fumes formation is studied by numerical modeling via description of separate processes inside the space charge regions near electrodes in the welding arc with consumable electrode. The modeling comprises the calculation of temperature profiles for electrons and heavy component, calculation of space distribution of gas components’ number densities, of gas particles’ mean free pathes, of electric potential and field, calculation of the heat transfer from electrode wire (anode) to molten pool (cathode). The formation of high temperature metal vapor from molten pool to environment as a function of arc current is demonstrated. The nucleation in the plasma of welding fumes is considered with taken into account ionization of vapor atoms via their interaction with nucleus surface. The growth of nucleus droplets via vapor condensation and coalescence is calculated. The coagulation of solid primary particles for various values of welding current is calculated and inhalable particle size distribution is demonstrated.

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Karpov, Sergiy, Valeryi Ruzhytskyi, Galyna Tolstolutskaya, Ruslan Vasilenko, Oleksandr Kuprin, and Sergiy Leonov. "Thermodynamic and Kinetic Parameters of the Processes of Deuterium Interaction with Tungsten Protective Coatings." 4, no. 4 (December 10, 2021): 99–106. http://dx.doi.org/10.26565/2312-4334-2021-4-11.

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The effect of radiation damage on the retention of deuterium in tungsten (W) was examined. A vacuum-arc plasma source with magnetic stabilization of the cathode spot was used for tungsten coatings preparation. W samples were treated with D ions at temperatures 300‑600 K with a fluence of (1 – 10) ·1020 D2+/m2 and ion energies of 12 keV/D2+. The influence of radiation damage on microstructure and accumulation of deuterium implanted in W samples at room temperature and after annealing have been studied. Thermal desorption (TD) spectroscopy was used to determine the D retained throughout the bulk of the sample. The structure of TD spectra represents the multi-stage process of deuterium release suggesting the trapping of gas atoms by a number of defect types. Computational evaluation of deuterium desorption within the framework of the diffusion-trapping model allows to associate characteristics of experimental TD spectra with specific trapping sites in the material. Experimental TD spectrum was fitted by assigning four binding energies of 0.55 eV, 0.74 eV, 1.09 eV and 1.60 eV for the peaks with maxima at 475, 590, 810 and 1140 K, respectively. The low temperature peak in the TD spectra is associated with desorption of deuterium bounded to the low energy natural traps, whereas the other peaks are related to the desorption of deuterium bounded to the high energy ion induced traps: monovacancies and vacancy clusters.

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Eriksson, Jens, Donatella Puglisi, Carl Strandqvist, Rickard Gunnarsson, Sebastian Ekeroth, Ivan G. Ivanov, Ulf Helmersson, Kajsa Uvdal, Rositza Yakimova, and Anita Lloyd Spetz. "Modified Epitaxial Graphene on SiC for Extremely Sensitive and Selective Gas Sensors." Materials Science Forum 858 (May 2016): 1145–48. http://dx.doi.org/10.4028/www.scientific.net/msf.858.1145.

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Two-dimensional materials offer a unique platform for sensing where extremely high sensitivity is a priority, since even minimal chemical interaction causes noticeable changes in electrical conductivity, which can be used for the sensor readout. However, the sensitivity has to be complemented with selectivity, and, for many applications, improved response- and recovery times are needed. This has been addressed, for example, by combining graphene (for sensitivity) with metal/oxides (for selectivity) nanoparticles (NP). On the other hand, functionalization or modification of the graphene often results in poor reproducibility. In this study, we investigate the gas sensing performance of epitaxial graphene on SiC (EG/SiC) decorated with nanostructured metallic layers as well as metal-oxide nanoparticles deposited using scalable thin-film deposition techniques, like hollow-cathode pulsed plasma sputtering. It is demonstrated that under the right modification conditions the electronic properties of the surface remain those of graphene, while the surface chemistry can be tuned to improve sensitivity, selectivity and speed of response to several gases relevant for air quality monitoring and control, such as nitrogen dioxide, benzene, and formaldehyde.

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Journal articles on the topic 'Interaction plasma/cathode'

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