Plasma Generation Research Articles

Influence of increased voltage on the nitriding zone during plasma nitriding

AbstractPlasma nitriding is an established process for increasing the corrosion and wear resistance of steel. However, the possibilities of modern developments in the field of high‐voltage plasma power supplies have been hardly investigated. For example, modern plasma generators allow improved arc management, which enable plasma nitriding at higher voltages.In the present work, the influence of increased voltage (up to 800 V) on the nitriding of a ferritic steel X38CrMoV5‐1 was investigated. It was found that the thickness of the compound layer increases with increasing voltage. Especially at short process times the increased voltage leads to increased growth. An increase in the nitriding depth was also observed.Furthermore, the increased voltage has an effect on the composition of the compound layer too. A moderate increase in ϵ‐nitride in the compound layer was observed.One explanation for the observed behavior is the over proportional increase in power with increasing voltage, indicating an increased ionization rate of the plasma. Due to this, more diffusible species would be available for nitriding.The presented results could be used to reduce process times, particularly where the formation of a compound layer is the aim of the process. An example of such a process is oxy‐nitriding.

Linear plasma device for the study of plasma-surface interactions

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.

Cooperation of the Plasma Reactor with a Converter Power Supply Equipped with a Transformer with Special Design

Plasma generation by means of electrical discharge requires specialized power supply systems. The applicability of plasma for various plasma processes depends on its parameters, and these, in turn, depend on the parameters of power supply systems. Arc plasma can be unstable, generating a lot of electromagnetic interference, overvoltage and overcurrent. The power system of a plasma reactor must guarantee good plasma control characteristics, be immune to disturbances and ensure good cooperation with the power grid. This article analyzes the cooperation of a three-phase plasma reactor, with a gliding arc discharge and a power supply system of a new type. This system integrates an AC/DC/AC converter and a five-column transformer with a special design in a single device. Using the properties of magnetic circuits, it is possible to integrate the functions of ignition and sustaining the burning of the discharge in the reactor in a single transformer. The proper design of the transformer is crucial to achieve the good cooperation of the AC/DC/AC converter with both the plasma reactor and the power supply network. The presented power supply design shows a number of positive features, predisposing it to powering arc plasma reactors.

Influence of electric potential-induced by atmospheric pressure plasma on cell response

Plasma irradiation leads not only active species, but also reactive chemical species, ultraviolet light, electric fields, magnetic fields, and shock waves. To date the effects of reactive chemical species have been mainly discussed. To understand the biological effect caused by an electric potential induced with an atmospheric-pressure plasma, the behavior of cell stimulated by electric potential was investigated using HeLa cell. The cell concentration assay revealed that less than 20% of cells inactivated by potential stimulation and the remained cells proliferate afterward. Fluorescent microscopic observation revealed that potential stimulation is appreciable to transport the molecules through membrane. These results show that potential stimulation induces intracellular and extracellular molecular transport, while the stimulation has a low lethal effect. A possible mechanism for this molecular transport by potential stimulation was also shown using numerical simulation based on an equivalent circuit of the experimental system including adhered HeLa cell. The potential formation caused by plasma generation is decisive in the contribution of plasma science to molecular biology and the elucidation of the mechanism underlying a biological response induction by plasma irradiation.

Advances and Challenges in Combustion Control of Radio Frequency Oscillating Plasma Discharge

Article Advances and Challenges in Combustion Control of Radio Frequency Oscillating Plasma Discharge Linyan Wang , Xiao Yu , Graham Reader , and Ming Zheng * Department of Mechanical, Automotive and Materials Engineering, University of Windsor, 401 Sunset Avenue, Windsor, N9B 3P4 Ontario, Canada * Correspondence: mzheng@uwindsor.ca Received: 18 July 2023 Accepted: 13 September 2023 Published: 20 September 2023 Abstract: Oscillating plasma (corona) ignition is a promising technique for producing a larger initial ignition volume for achieving cleaner combustion. The oscillating plasma system provides a quick response to the ignition command compared with the conventional transistor-coil-ignition systems (TCI). Subsequently, the shorter combustion duration contributes to further improvement of engine efficiency under lean/diluted conditions. The challenges of oscillating plasma ignition appear under elevated background pressures, mostly owing to fewer plasma streamers and even void discharge, thus the advantage of oscillating plasma discharge over spark discharge is compromised. To suffice the industrial applications, the challenges of plasma generation and control platforms are investigated and discussed in this work. The challenges include ignition control, background condition impacts, and other external disturbances. A flexible modulation for oscillating plasma generation is established, with the measurements of discharge voltage and current. High-speed imaging, simultaneous with electrical waveform measurements is applied to record the plasma formation and flame propagation. This research provides advances in the ignition control for the oscillating plasma discharge, adding a foundation and reference for the oscillating plasma diagnostics under engine-like conditions with variations of pressure, temperature, gas composition, and flow pattern.

Influence of dispersion on dynamics of the anti-Stokes broadening of the femtosecond pulse spectrum during filamentation in fused silica

Numerical simulation methods are used to study the spectral transformation of a femtosecond wave packet during filamentation in fused silica under conditions of normal, zero, and anomalous group velocity dispersion. It is shown that during plasma generation that causes phase modulation of the light field, a rapid anti-Stokes broadening of the spectrum occurs. It was established that the short-wavelength shift of the broadband supercontinuum spectrum is much larger in case of anomalous group velocity dispersion than in case of normal and zero dispersion. The influence of the wave packet energy on the spectrum broadening dynamics is considered. Estimates of the numerical scheme parameters are obtained based on the dispersion analysis of the process of broadband supercontinuum propagation in a medium.

Influence of specific energy inhomogeneity on the CO2 splitting performance in a high-power plasma jet

Plasma-based CO2 conversion is a promising pathway towards greenhouse gas recycling. In the corresponding research field, various types of plasma reactors are applied for carbon dioxide dissociation. So far, spatial inhomogeneities of the specific energy (SEI) distribution in plasma generators, e.g., induced by non-uniform heating or an inhomogeneous mass distribution, are not the focus of the investigations. In this work, the spatial inhomogeneity of mass-specific enthalpy in the plasma jet of the inductive plasma generator IPG4 at the Institute of Space Systems (IRS) is examined. For this purpose, the mean mass-specific enthalpy as well as the radial distribution of the local enthalpy are measured using plasma probes. Moreover, the influence of the determined specific enthalpy inhomogeneity on the CO2 splitting performance is quantified. It is shown that an inhomogeneous radial distribution of the specific energy can significantly lower the carbon dioxide conversion, compared to a homogeneous case. With regards to IPG4, the performance reduction is 16%.

Novel approach for recovering lithium from simulated aqueous solutions using carbon dioxide microwave plasma

An approach for recovering lithium from aqueous solutions containing lithium was developed via lithium carbonate (Li2CO3) precipitation through a carbonate mineralization reaction. To enhance the lithium recovery rate, carbon dioxide (CO2) plasma was used to precipitate lithium as Li2CO3. The Li2CO3 precipitate, filtered from the aqueous solution, was analyzed by X-ray diffraction and then confirmed to be Li2CO3 by comparing with commercial Li2CO3. Comparative experiments between CO2 gas and CO2 plasma revealed a significant improvement in the lithium recovery efficiency by 3 times on using CO2 plasma. The amount of remaining lithium in the aqueous solution before and after the reaction was quantified and analyzed by inductively coupled plasma mass spectrometry. Plasma generation was achieved using a 2.45 GHz microwave plasma torch by utilizing CO2 as the discharge gas and allowing immediate reaction with the aqueous solution. Plasma characteristics were analyzed using an optical emission spectrometer to observe the emitted radicals and calculate the rotational temperature of the CO2 plasma. The future potential of this technology for the recovery of lithium from seawater was also investigated.

Continuous pulse advances in the negative ion source NIO1

Consorzio RFX and INFN-LNL have designed, built and operated the compact radiofrequency negative ion source NIO1 (Negative Ion Optimization phase 1) with the aim of studying the production and acceleration of H- ions. In particular, NIO1 was designed to keep plasma generation and beam extraction continuously active for several hours. Since 2020 the production of negative ions at the plasma grid (the first grid of the acceleration system) has been enhanced by a Cs layer, deposited though active Cs evaporation in the source volume. For the negative ion sources applied to fusion neutral beam injectors, it is essential to keep the beam current and the fraction of co-extracted electrons stable for at least 1 h, against the consequences of Cs sputtering and redistribution operated by the plasma. The paper presents the latest results of the NIO1 source, in terms of caesiation process and beam performances during continuous (6 ÷ 7 h) plasma pulses. Due to the small dimensions of the NIO1 source (20 cm×∅10 cm), the Cs density in the volume is high (1015 ÷ 1016 m-3) and dominated by plasma-wall interaction. The maximum beam current density and minimum fraction of co-extracted electrons were respectively about 30 A/m2 and 2. Similarly to what done in other negative ion sources, the plasma grid temperature in NIO1 was raised for the first time, up to 80 °C, although this led to a minimal improvement of the beam current and to an increase of the co-extracted electron current.

Discharge characteristics of an atmospheric pulsed microwave Ar/CF4 plasma jet

The atmospheric fluorocarbon plasma is widely used in surface modification of polymers. Recently, the pulsed microwave Ar/CF4 plasma jet is proved to be a promising atmospheric fluorocarbon plasma source with good performance. In this paper, the discharge characteristics of the pulsed microwave Ar/CF4 plasma jet are studied systematically. The discharge morphologies, ionization processes, optical emission spectra, and electron densities are obtained by a digital camera, an intensified charge coupled device, a fiber spectrometer, and a home-made microwave Rayleigh scattering device, respectively. The influences of the plasma operation parameters on the discharge characteristics are investigated, and the microwave input power and CF4 volume fraction are optimized. The results provide a basis for the generation and surface modification application of high-performance atmospheric fluorocarbon plasma.

INFLUENCE OF CONFIGURATION OF THE ELECTRODE SYSTEM OF A COAXIAL MAGNETO PLASMA ACCELERATOR ON ARC DISCHARGE FORMATION AND DEVELOPMENT

Link for citation: Tsimmerman A.I., Shanenkov I.I., Nassyrbayev A.R., Nikitin D.S., Sivkov A.A. Influence of configuration of the electrode system of a coaxial magneto plasma accelerator on arc discharge formation and development. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 8, рр. 39-50. In Rus. The relevance of the research is explained by a wide range of practical areas, where various plasma generators can be used, including analytical devices, technological installations, tokamaks, ion and plasma engines, satellites, laser technology, as well as by the possibility of applying them for both producing coatings on various surfaces and synthesizing fine and nanopowders. The main aim of the research is to determine the best way to initiate an arc discharge in the acceleration channel of the coaxial magnetoplasma accelerator, to estimate the effect of the plasma formation zone configuration on the electrodynamic loads of the accelerator, and to calculate the efficiency of conversion of stored energy to supplied one. Objects: coaxial magnetoplasma accelerator, arc discharge initiation, central electrode, electrode-barrel, plasma formation zone. Methods: experiment, plasma dynamic synthesis, measurement and registration of pulsed currents and voltages, electrical erosion measurement by means of weighing the eroding electrode-bore, high-speed photoregistration of the plasma jet. Results. Two methods of arc discharge initiation using metal wires and graphitization were considered. It is established that they do not affect the energy parameters of the plasma dynamic synthesis, but the graphitization looks preferable due to the greater processability of the procedure that provides easy accelerator preparation and reliability of its operation. The possibility of reducing the arc discharge current amplitude by 29 % with increasing the plasma formation zone length from 5,5 to 11,5 mm was established that results in reducing electrodynamic loads on all system nodes. The optimal plasma formation zone length of 9,5 mm was determined to provide obtaining a high efficiency of conversion of stored energy into supplied energy and reliability of the system operation.

Extreme Ultraviolet Radiation Sources from Dense Plasmas

The concept of dense and hot plasmas can be used to build up powerful and brilliant radiation sources in the soft X-ray and extreme ultraviolet spectral range. Such sources are used for nanoscale imaging and structuring applications, such as EUV lithography in the semiconductor industry. An understanding of light-generating atomic processes and radiation transport within the plasma is mandatory for optimization. The basic principles and technical concepts using either a pulsed laser or a gas discharge for plasma generation are presented, and critical aspects in the ionization dynamics are outlined within the framework of a simplified atomic physics model.

High Entropy Oxides Synthesis by Rapid Plasma Generation with Applications Towards Electrocatalytic Hydrogen Generation

It has been challenging over the past three decades to find viable energy alternatives with higher efficiency and lower cost to beat the non-friendly and commercially dominant hydrocarbon energy sources. Hydrogen is deemed to be one of the most prominent candidates, as a green fuel. Hydrogen can be generated in abundance from water splitting. Utilization of hydrogen in fuel cells, with no doubt, produces no harmful gases. Nevertheless, the two parts of the technology: hydrogen production and reduction are cumbersome. Both processes rely on kinetically sluggish electrocatalytic reactions. Enormous research efforts have been spent, with thousands of studies presented in literature, despite the technology left with a dim light shed on from commercial and practical point of views. Many materials-related challenges are hindering the flourishing of green hydrogen technology, where poor catalyst durability is a major challenge, despite being made from very expensive elements (e.g., Ir, ru or Pt). Therefore, gigantic effort of research has been devoted to find inexpensive alternatives. Transition metals showed interesting performance towards water splitting (e.g., oxygen evolution (OER)).Recent research showed that electrocatalysts designed by alloying two or more elements (e.g., transition metals) showed promising enhancement in catalytic activity and durability due to synergistic effects from alloying, such as strain engineering or electron exchange. The potential of the alloying approach is constrained by standard synthesis methods (e.g., wet chemistry and thermal decomposition techniques) due to the governing thermodynamics rules (e.g., miscibility of the different alloying elements). That renders the synthesis of high entropy alloys (HEA), with more than 3 elements, to be complicated and tedious to achieve by those conventional methods.In the presented talk we are presenting the utilization of microwaves to generate plasma to synthesize metastable high entropy oxides (HEA) and their outstanding catalytic performance towards OER, in correlation to their unique chemistries and structures. Plasma generated enable temperature increase of the precursor substrate to elevated levels (~1000s °C), in conjunction with rapid cooling, within seconds range. Our results show successful synthesis of non-noble metals HEA NPs, possessing higher catalytic activity than IrO2 catalyst for OER. The nature of the alloying elements dictates OER activity by promoting different oxidation states of the catalytically active transition metals (e.g., Fe, Ni and Co). Our developed techniques resulted in formation of super-strong metal-carbide bonds “chemically welding” HEA NP to the catalyst support.

(Digital Presentation) A Review on the Control of Biofilms by Cold-Plasma Technology

Today, biofilm infection is considered a challenge in the field of medicine and biomedical physics and engineering, as it includes 80% of infections worldwide. The complex architecture of the matrix of the extracellular polymeric substance of the biofilm, which houses the microbial cells, is resistant to antimicrobials and detergents. Cold Plasma anti-bio film application is a novel solution to address this challenge. This review study focuses on different parameters and factors affecting the mechanism of plasma-biofilm interaction in two types: direct and indirect processing. The first phase, the direct application of plasma, focuses on the direct processing of biofilms by cold plasma generators. The second phase, the indirect application of plasma is dealt with plasma surface engineering for biomaterial and medical devices which are in contact with the human body. As is known reduction in microbial load and biofilm removal by direct plasma processing is achievable and efficient. This microbial reduction also can happen by plasma surface engineering as an indirect solution, in which the plasma-treated biomaterial surface will gain an antimicrobial property and consequently mitigate biofilm growth. Moreover, the penetration depth of plasma in biofilms and the application of plasma surface pretreatment with 3D printing as a next-generation manufacturing approach have been reviewed. This review study sheds light on the efficient factors in this mechanism. This clarification helps how to optimize the control of biofilms by cold plasma technology.

Cold Atmospheric Pressure Plasma Jet and Plasma Lamp Interaction with Plants: Electrostimulation, Reactive Oxygen and Nitrogen Species, and Side Effects

Cold atmospheric pressure plasma (CAPP) treatment is a highly effective method of protecting seeds, plants, flowers, and trees from diseases and infection and significantly increasing crop yields. Here we found that cold atmospheric pressure He-plasma jet (CAPPJ) can also cause side effects and damage to plants if the plasma exposure time is too long. Reactive oxygen and nitrogen species (RONS), electromagnetic fields, and ultraviolet photons emitted by CAPPJ can cause both positive and negative effects on plants. CAPPJ can interact with biological tissue surfaces. The plasma lamp has no visible side effects on Aloe vera plants, cabbage, and tomatoes. A plasma lamp and a cold atmospheric pressure plasma He-jet cause strong electrical signaling in plants with a very high amplitude with frequencies equal to the frequency of plasma generation. The use of plasma lamps for electrostimulation of biological tissues can help to avoid side processes in biological tissues associated with the generation of RONS, UV photons, and direct interaction with cold plasma. CAPP technology can play an important role in agriculture, medicine, the food industry, chemistry, surface science, material science, and engineering applications without side effects if the plasma exposure is short enough.

Optical fiber application of the Improved Generalized Riccati Equation Mapping method to the perturbed nonlinear Chen-Lee-Liu dynamical equation

This work considers the improved generalized Riccati equation mapping (IGREM) technique with its Bäcklund transformation to obtain the wave solutions of the perturbed Chen-Lee-Liu (CLL) equation. The CLL equation actually depicts pulse propagation in optical fibers and plasma. We utilize proposed technique to obtain hyperbolic, periodic trigonometric, rational and exponential function solutions. To make this work worthy and for efficient illustration of this methodology, 3D, contours and 2D plots of some selected solutions are constructed by selecting the values of involved parameters. The results of this paper prove that the used method is effective to improve the nonlinear dynamical behavior of a system.

Comparative Thrombin Generation in Animal Plasma: Sensitivity to Human Factor XIa and Tissue Factor.

Preclinical evaluation of drugs in animals helps researchers to select potentially informative clinical laboratory markers for human trials. To assess the utility of animal thrombin generation (TG) assay, we studied the sensitivity of animal plasmas to triggers of TG, human Tissue Factor (TF), and Activated Factor XI (FXIa). Pooled human, mouse, rat, guinea pig, rabbit, bovine, sheep, and goat plasmas were used in this study. TF- or FXIa-triggered TG and clotting were measured via fluorescence and optical density, respectively. Thrombin peak height (TPH) and time (TPT), clot time (CT), and fibrin clot density (FCD) were all analyzed. The trigger low and high sensitivity borders (LSB and HSB) for each assay parameter were defined as TF and FXIa concentrations, providing 20 and 80% of the maximal parameter value, unless the baseline (no trigger) value exceeded 20% of the maximal, in which case, LSB was derived from 120% of baseline value. Normal human samples demonstrated lower TPH HSB than most of the animal samples for both TF and FXIa. Animal samples, except mice, demonstrated lower TPT LSB for FXIa versus humans. Most rodent and rabbit samples produced baseline TG in the absence of TG triggers that were consistent with the pre-activation of blood coagulation. FCD was not sensitive to both TF and FXIa in either of the plasmas. Animal plasmas have widely variable sensitivities to human TF and FXIa, which suggests that optimization of trigger concentration is required prior to test use, and this complicates the extrapolation of animal model results to humans.

Using the self-discharge electromagnetic generator fi eld to control the quality of potato tubers at the stages of storage

The article discusses a method for treating tubers with an electromagnetic fi eld (EMF) generated by a self-discharge high-frequency plasma generator before storage. The infl uence of this type of EMF on the activation of the metabolic processes of biological objects, increasing their resistance to damage by microorganisms during storage and contributing to the reduction of losses, is shown.

Plasma Energy Loss by Cathode Heat Conduction in a Vacuum Arc: Cathode Effective Voltage

The importance of understanding the energy loss specifics by the cathode for vacuum arc metallic plasma generation and its applications were emphasized. To this end, the heat conduction losses per unit current were characterized by the cathode effective voltage uef, which is weakly dependent on the current. In this paper, a physical model and a mathematical approach were developed to describe the energy dissipation due to heat conduction in the cathode body, which is heated by energy outflowed from the adjacent plasma. The arc plasma generation was considered by taking into account the kinetics of the heavy particle fluxes in the non-equilibrium layer near the vaporizing surface. The phenomena of electric sheath, heat and mass transfer at the cathode were taken into account. The self-consistent numerical analysis was performed with a system of equations for a copper cathode spot. The transient analysis starts from the spot initiation, modeled by the plasma arising at the initial time determined by the kind of arc triggering, up to spot development. The results of the calculations show that the cathode effective voltage uef is determined by the cathode temperature as a function of spot time. The calculated evolution of the voltage uef shows that the steady state of uef is approximately 7 V, and it is reached when the cathode temperature reaches a steady state at approximately one microsecond. This essential result provides an explanation for the good agreement with the experimental cathode effective voltage (6–8 V) measured for the arc duration from one millisecond up to a few seconds.

Effect of cold plasma on lipid oxidation of fish and fish‐based products: a review

SummaryLipid oxidation is a major concern in preserving fish and its products, as it affects their quality, shelf life, and consumer acceptance. Cold plasma technology has emerged as a promising method for extending the shelf life of perishable products, including fish. However, the impact of cold plasma on lipid oxidation remains uncertain, as studies have reported conflicting findings. This review provides an up‐to‐date overview of the effects of cold plasma treatment on lipid oxidation in fish and fish‐based products, synthesising existing literature in the field. A comprehensive analysis of factors such as plasma generation techniques, treatment parameters, fish species, and lipid composition is conducted to elucidate the observed discrepancies in outcomes. In conclusion, current research suggests that moderate oxidation does not have adverse effects on overall sensory quality and may even enhance the flavour of fish. The degree of oxidation can be controlled through plasma parameters, thereby improving the quality of fish and fish products.