Hasil untuk "Plasma physics. Ionized gases"

Irfan Maulana Ahmad, Abd. Djamil Husin, Duong Thanh Tai et al.

Nuclear fusion, the process of combining light nuclei to form heavier nuclei, offers a promising pathway to sustainable clean energy with minimal radioactive waste. The Lawson criterion, expressed as the product of plasma density, confinement time, and temperature, establishes the conditions required for ignition and net energy gain. This study investigates the Lawson criterion for proton-boron-11 (p-11B) fusion across ion temperatures of 75–500 keV, incorporating fusion reactivity data from Tentori-Belloni and Nevins-Swain, as well as energy losses from bremsstrahlung radiation under different electron-to-ion temperature ratios (TeTi= 1, 0.5, 0.25). The Tentori-Belloni dataset yields higher fusion reactivity than Nevins-Swain, resulting in more favorable Lawson values. Net energy production is achieved only when Te<Ti, with optimal operating windows identified at 190–330 keV for Te= 0.5Ti and 125–500 keV for Te= 0.25Ti. At Ti< 230 keV, the Lawson criterion decreases due to plasma instabilities and confinement limitations; in this work, radiative losses are evaluated using Zeff=2.4 derived from the p-11B fuel mixture (npnB=90:10) only, while external impurity contributions are not explicitly modeled. For Ti> 230 keV, the Lawson criterion increases, reaching characteristic minima around 330 keV and 500 keV. These thresholds represent the minimum conditions required to achieve ignition and sustain a self-sufficient fusion reaction. The minimum Lawson values obtained were 1.3 × 1022 m−3s (no radiation), 1.2 × 1023 m−3s (Te= 0.5Ti), and 1.5 × 1022 m−3s (Te= 0.25Ti). These findings highlight the critical role of accurate cross-section data and electron-ion temperature control in advancing aneutronic p-11B fusion toward practical, self-sustained clean energy systems.

Whitney Talavera Ramos, Adrián Tellería Narváez, Lucas Dos Santos et al.

This study investigates the synthesis and characterization of metakaolin-based geopolymers for the immobilization of simulated aluminum-containing radioactive liquid waste. Two kaolin precursors with different Si/Al ratios and purities were calcined between 700 °C and 900 °C. Geopolymers were prepared using a sodium silicate–NaOH activating solution (10 M NaOH) with and without sand, and cured at 60 °C. The effects of curing time and simulated liquid waste incorporation (10–40 wt%) on mechanical strength and microstructural development were evaluated through compressive strength tests, XRD, and SEM analyses. The results showed that curing time influenced strength development. Incorporation of simulated liquid waste generally reduced compressive strength, probably due to increased porosity and decreased metakaolin (MK) dissolution; however acceptable performance was achieved at a 20 wt% addition for MKSR-based geopolymers. XRD analyses confirmed the formation of an amorphous band between 25° and 35° typical of geopolymer structures. In contrast, MKS-based geopolymers exhibited lower mechanical strength and incomplete gel formation under the tested conditions. These findings demonstrate the potential of local precursor MKSR metakaolin-based geopolymers as promising matrices for the immobilization of aluminum-bearing radioactive liquid waste.

Alex Leide, Weicheng Zhong, Isabel Fernandez-Victorio et al.

Retention of hydrogen isotopes is a critical concern for operating fusion reactors as retained tritium both activates components and removes scarce fuel from the fuel cycle. Radiation-induced displacement damage in SiC influences the retention of hydrogen isotopes compared to pristine SiC. Deuterium retention in neutron irradiated high purity SiC has been compared to different microstructures of non-irradiated high purity SiC using thermal desorption spectroscopy after gas charging and low energy ion implantation. Experimental results show lower deuterium retention in single crystal SiC than in polycrystal SiC indicating that grain boundaries are key trapping features in unirradiated SiC. Deuterium is released at lower temperatures in neutron irradiated polycrystal SiC compared to pristine polycrystal SiC, suggesting weaker trapping by radiation-induced defects compared to grain boundary trapping sites in the pristine materials. Low energy ion implantation caused a high deuterium release temperature, highlighting the sensitivity of deuterium release behaviour to radiation defect characteristics. First principles calculations have been conducted to identify energetically favourable trapping sites in SiC at the HABcVSi and HTSiVC complexes, and migration barriers between interstitial sites. This helps interpret experimental results and derive effective diffusivity of hydrogen isotopes in SiC in the presence of vacancies.

Yangyang Ma, Wenle Song, Junlei Zhao et al.

The Thomas–Fermi model and its quantum and exchange corrections with mathematic manipulations and numerical approaches are primarily investigated. The reduced ideal electron chemical potential is adopted as the initial value for the iterative solution of the Thomas–Fermi model. A new transformation for the quantum and exchange equations is proposed to apply the boundary conditions easily. Both the Thomas–Fermi equation and correction equations are solved with the Runge–Kutta algorithm. The mathematical difficulties in controlling the computing accuracy of the equations containing the Fermi–Dirac integral are settled. The equation of state, based on the Thomas–Fermi model with its quantum and exchange corrections, is constructed and compared with relevant data.

Mingyan Chen, Chenhong Wang, Tian Xie et al.

This study investigated the inactivation effect and influencing factors of cold atmospheric plasma (CAP) treatment with <i>Salmonella typhimurium</i> and <i>Staphylococcus aureus</i> populations on three food contact materials (FCMs)—kraft paper, 304 stainless steel, and glass. The CAP was generated as an atmospheric helium plasma jet (15 kV, 10.24 kHz, He 4 L/m), and the experimental results indicated that its inactivation effects on two bacterial species gradually increased as the plasma treatment duration increased (0, 1, 2, 3, 4, and 5 min). Three classical sterilization kinetic models (Log-linear, Weibull, and Log-linear + Shoulder + Tail) were employed to evaluate the inactivation efficiency of plasma against bacteria FCMs. Combined with the coefficient of determination (<i>R</i>²), accuracy factor (<i>A</i>_f), and bias factor (<i>B</i>_f), together with the root mean square error (RMSE), it can be concluded that the Log-linear + Shoulder + Tail model had the highest fitting degree among the three sterilization kinetics models. <i>Salmonella typhimurium</i> exhibited weaker resistance than <i>Staphylococcus aureus</i> to the same CAP treatment. Under the same conditions, CAP had the strongest bactericidal effect on the bacteria on the glass surface, followed by those on the 304 stainless steel, and had the weakest bactericidal effect on the bacteria on the kraft paper surface, which might be related to the surface hydrophilicity and roughness of the FCMs. The above results indicated that CAP’s inactivation effect may be influenced by the microbial species as well as the surface characteristics of FCMs. This study provides useful information for future applications of CAP in enhancing food safety.

Stephan Fritzsche, Houke Huang, Aloka Kumar Sahoo

Recent advances in non-local thermodynamic equilibrium (non-LTE) plasma simulations, for example in modeling kilonova ejecta, have emphasized the need for consistent and reliable atomic data. Unlike LTE modeling, non-LTE calculations must include a consistent treatment of various photon-induced and collisional processes in order to describe realistic electron and photon distributions in the plasma. However, the available atomic data are often incomplete, inconsistently formatted, or even fail to indicate the main dependencies on the level structure and plasma parameters, thus limiting their practical use. To address these issues, we have extended <span style="font-variant: small-caps;">Jac</span>, the Jena Atomic Calculator (version v0.3.0), to provide direct access to relevant cross sections, plasma rates, and rate coefficients. Emphasis is placed on photoexcitation and ionization processes as well as their time-reversed counterparts—photo-de-excitation and photorecombination. Whereas most of these data are still based on empirical expressions, their dependence on the ionic level structure and plasma temperature is made explicit here. Moreover, the electron and photon distributions can be readily controlled and adjusted by the user. This transparent representation of atomic data for photon-mediated processes, together with a straightforward use, facilitates their integration into existing plasma codes and improves the interpretation of high-energy astrophysical phenomena. It may support also more accurate and flexible non-LTE plasma simulations.

Vladislav Maksimov, Adi Haim, Ron Grikshtas et al.

Time- and space-resolved radiation emitted by the plasma produced by a 0.8 ns duration at full width half maximum, ~600 MW maximum power microwave (~9.6 GHz) pulse traversing a hydrogen-, helium-, or air-filled circular waveguide, is studied. Gas ionization by microwaves is an old subject but the regime investigated in the present experimental research, of very high-power microwaves and very short pulses using modern diagnostic tools, is new and follows a series of new studies performed so far only in our laboratory, revealing non-linear phenomena never observed before. In the present research, plasma radiation is observed along a slit made in a circular waveguide wall by either an intensified fast frame camera or a streak camera. Using calibrated input and output couplers, the transmission and reflection coefficients of the high-power microwaves were determined over a broad range of gas pressures, 0.1 kPa < <i>P</i> < 90 kPa. It was found that the intensity of the plasma light emission increases significantly after the high-power microwave pulse has left the waveguide. Depending on pressure, the radiation is either uniform along the slit, while the front of the emitted light follows the microwave pulse at a velocity close to its group velocity, or it remains in the vicinity of the input window, indicating that the plasma density is above critical density. It was also found that the radial distribution of radiation depends on pressure. At pressures <10 kPa, when the electron oscillatory energy reaches 20 keV close to the waveguide axis, light emission forms faster near the waveguide walls, where the ionization rate is maximal. Otherwise, when pressure is >80 kPa, light emission is most intense on the axis where the electron oscillatory energy is ~100 eV and the ionization rate is maximal. We also studied the UV radiation from the plasma, the duration of which was found to be longer than the duration of visible light emission. This indicates the existence of energetic electrons for tens of ns after the high-power microwave pulse has left the observation region. Considering that the emitted light intensity depends on the plasma density and temperature, the observed data may be used for a comparison with the results of collisional radiative models if the electron time and spatial energy distribution is known.

Pietro Mandracci

Capacitively coupled plasma (CCP) discharges working at low pressure are widely used for the synthesis of thin films and the modification of the surface properties of materials. Due to their importance, considerable research was carried out over the years to understand their working mechanisms, and the physical properties of the CCP discharges were measured by many research groups, while simulations of their characteristics were often performed using both fluid and kinematic models. However, most of the simulation and characterization work found in the literature is focused on the discharge steady-state characteristics, since most of the applications rely on its properties, while less information is available on the early stages. In fact, the initial stages of CCP plasma discharges are of great importance to improve the understanding of their ignition process as well as to figure out the working mechanism of pulsed discharges, the use of which has increased in importance in recent years. In this work, a review of the results published in recent years concerning the physical mechanisms involved in the very first stages of low-pressure CCP discharges is presented, focusing on the first few microseconds of discharge time.

Antoine Herrmann, Joëlle Margot, Ahmad Hamdan

In the context of plasma–liquid interactions, the phase of discharge ignition is of great importance as it may influence the properties of the produced plasma. Herein, we investigated the influence of voltage rising time (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi mathvariant="sans-serif">τ</mi><mrow><mi mathvariant="normal">r</mi><mi mathvariant="normal">i</mi><mi mathvariant="normal">s</mi><mi mathvariant="normal">e</mi></mrow></msub></mrow></semantics></math></inline-formula>) on discharge ignition in air as well as on discharge propagation on the surface of water. Experimentally, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi mathvariant="sans-serif">τ</mi></mrow><mrow><mi mathvariant="normal">r</mi><mi mathvariant="normal">i</mi><mi mathvariant="normal">s</mi><mi mathvariant="normal">e</mi></mrow></msub></mrow></semantics></math></inline-formula> was adjusted to 0.1, 0.4, 0.6, and 0.8 kV/ns using a nanosecond high-voltage pulser, and discharges were characterized using voltage/current probes and an ICCD camera. Faster ignition, higher breakdown voltage, and greater discharge current (peak value) were observed at higher <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi mathvariant="sans-serif">τ</mi></mrow><mrow><mi mathvariant="normal">r</mi><mi mathvariant="normal">i</mi><mi mathvariant="normal">s</mi><mi mathvariant="normal">e</mi></mrow></msub></mrow></semantics></math></inline-formula>. ICCD images revealed that higher <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi mathvariant="sans-serif">τ</mi></mrow><mrow><mi mathvariant="normal">r</mi><mi mathvariant="normal">i</mi><mi mathvariant="normal">s</mi><mi mathvariant="normal">e</mi></mrow></msub></mrow></semantics></math></inline-formula> also promoted the formation of more filaments, with increased radial propagation over the water surface. To further understand these discharges, a previously developed 2D fluid model was used to simulate discharge ignition and propagation under various <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi mathvariant="sans-serif">τ</mi></mrow><mrow><mi mathvariant="normal">r</mi><mi mathvariant="normal">i</mi><mi mathvariant="normal">s</mi><mi mathvariant="normal">e</mi></mrow></msub></mrow></semantics></math></inline-formula> conditions. The simulation provided the spatiotemporal evolution of the E-field, electron density, and surface charge density. The trend of the simulated position of the ionization front is similar to that observed experimentally. Furthermore, rapid vertical propagation (<1 ns) of the discharge towards the liquid surface was observed. As <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi mathvariant="sans-serif">τ</mi></mrow><mrow><mi mathvariant="normal">r</mi><mi mathvariant="normal">i</mi><mi mathvariant="normal">s</mi><mi mathvariant="normal">e</mi></mrow></msub></mrow></semantics></math></inline-formula> increased, the velocity of discharge propagation towards the liquid increased. Higher <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi mathvariant="sans-serif">τ</mi></mrow><mrow><mi mathvariant="normal">r</mi><mi mathvariant="normal">i</mi><mi mathvariant="normal">s</mi><mi mathvariant="normal">e</mi></mrow></msub></mrow></semantics></math></inline-formula> values also led to more charges in the ionization front propagating at the water surface. The discharge ceased to propagate when the charge number in the ionization front reached 0.5 × <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mrow><mn>10</mn></mrow><mrow><mn>8</mn></mrow></msup></mrow></semantics></math></inline-formula> charges, irrespective of the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi mathvariant="sans-serif">τ</mi></mrow><mrow><mi mathvariant="normal">r</mi><mi mathvariant="normal">i</mi><mi mathvariant="normal">s</mi><mi mathvariant="normal">e</mi></mrow></msub></mrow></semantics></math></inline-formula> value.

Maryam Reza, Farbod Faraji, Aaron Knoll

The results from a wide-ranging parametric investigation into the behavior of the collisionless partially magnetized plasma discharge of three propellants—xenon, krypton, and argon—are reported in this two-part article. These studies are performed using high-fidelity reduced-order particle-in-cell (PIC) simulations in a 2D configuration that represents an axial–azimuthal cross-section of a Hall thruster. In this part I paper, we discuss the effects of discharge voltage and current density (mass flow rate). Our parametric studies assess the spectra of the resolved instabilities under various plasma conditions. We evaluate the ability of the relevant theories from the literature to explain the variations in the instabilities’ characteristics across the studied plasma parameter space and for various propellants. Moreover, we investigate the changes in the electrons’ cross-magnetic-field transport, as well as the significance of the contribution of different momentum terms to this phenomenon across the analyzed cases. In terms of salient observations, the ion acoustic instability (IAI)-related modes are found to be dominant across the simulation cases, with the ion transit time instability also seen to develop at low current density values. Across the explored parameter space, the instabilities have the main contributions to the electrons’ transport within the plume region. The peak of the electric momentum force term, representing the effect of the instabilities, overall shifts toward the plume as either the current density or the discharge voltage increases. The numerical findings are compared against relevant experimental observations reported in the literature.

M. S. Espain, M. S. Espain, M. S. Espain et al.

The distribution of boron in biological samples coming from BNCT protocols can be determined by the analysis of autoradiographic images formed by nuclear tracks on polymeric detectors. The tissue section is first explored to delimit regions of interest (ROIs), and then it is removed in order to reveal nuclear tracks through an etching process. A quantitative autoradiographic technique was developed to measure the boron concentration in the sample by counting the nuclear tracks on the detector. However, under certain circumstances, rapid measurements of boron distribution are required. For that purpose, a methodology was developed, allowing a rapid and easy determination of boron concentration and distribution in a tissue section by measuring grey levels in the corresponding high fluence autoradiographic image (HFA). The grey levels are then converted to optical density values which are then correlated with boron concentration values. In order to validate the technique, consecutive sections of several tissue samples were analyzed by the conventional counting method and by HFA. The image analysis and boron concentration estimation can be carried out in under 15 min, and relative differences between zones can be easily determined.

Arturo Popoli, Fabio Ragazzi, Giacomo Pierotti et al.

We introduce a fluid computational model for the numerical simulation of atmospheric pressure dielectric barrier discharge plasmas. Ion and neutral species are treated with an explicit drift diffusion approach. The Boltzmann relation is used to compute the spatial distribution of electrons as a function of the electrostatic potential and the ionic charge density. This technique, widely used to speed up particle and fluid models for low-pressure conditions, poses several numerical challenges for high-pressure conditions and large electric field values typical of applications involving atmospheric-pressure plasmas. We develop a robust algorithm to solve the non-linear electrostatic Poisson problem arising from the Boltzmann electron approach under AC electric fields based on a charge-conserving iterative computation of the reference electric potential and electron density. We simulate a volumetric reactor in dry air, comparing the results yielded by the proposed method with those obtained when the drift diffusion approach is used for all charged species, including electrons. We show that the proposed methodology retains most of the physical information provided by the reference modeling approach while granting a substantial advantage in terms of computation time.

Francisco Trivinho-Strixino, Adriana O. Delgado-Silva, Janaina S. Santos et al.

In this study, 6061 Al alloy was galvanostatically anodized under the Plasma Electrolytic Oxidation (PEO) condition. A factorial design of 2² was carried out using two variables (anodization time and presence of silver in the electrolyte) on two levels, i.e., 20 and 60 min of anodization and the absence/presence of silver ions in the electrolyte. The Al anodization was performed in sodium silicate electrolyte, applying a constant current density of 20 mA cm⁻². The oxide characterization was performed by Scanning Electron Microscopy (SEM), surface roughness analysis (RMS), Energy Dispersive Spectroscopy (EDS), Rutherford Backscattered Spectroscopy (RBS), and Grazing Incidence X-ray Diffraction (GIXRD). The SEM micrographs revealed an irregular porous structure with cracks on the oxide surface composed of a thin crystalline layer of γ-Al₂O₃ over the Al substrate. From EDS and RBS analysis, it was possible to identify the elements Al, O, Si, Ag, and Na, demonstrating that a shorter anodization time (20 min) led to a significant amount of silver deposits on the outer layer of the oxide coating, mainly deposited in the surroundings of the pores. Conversely, the silver content on the PEO film anodized for 60 min was meager. These results demonstrated that the anodization time was the critical control variable for the amount of silver deposited over the oxide film. The shorter the anodizing time, the higher the silver content on the PEO coating.

Wolfgang Voigt, Daniela Freyer

Anhydrite and gypsum are omnipresent in sedimentary rocks of all types. They occur as massive layers or are distributed within other geological formations as in clays. Understanding the conditions of formation and the stability of the hydrated and anhydrous form of calcium sulfate is crucial in an elucidation of the genesis of the geological formations envisaged as potential host rock for radioactive waste disposal. Estimations of the temperature, where gypsum is dehydrated to anhydrite in water vary between 30°C and 60°C. The extremely slow crystallization kinetics of anhydrite at T &lt; 90°C prevents a direct determination of this transition temperature. In the present work the different approaches to fix this temperature are discussed. It is shown that careful assessment of solubility data and calorimetric measurements yields a transition temperature of 42°C ± 1°C. For results essentially deviating from this value methodic deficiencies are revealed and discussed. Thus, a long-standing discussion about the thermodynamic aspect of the gypsum-anhydrite conversion can be closed, not the kinetic part.

Alexei Yu. Chirkov, Kirill D. Kazakov

The feasibility of positive energy yield in systems with the p–¹¹B reaction is considered here by considering refined (optimistic) data on the reaction rate. The analysis was carried out within the traditional framework for magnetic confinement systems, but without taking into account a particular type of plasma configuration. The energy balance was considered both for the ions and electrons. The balance of particles includes all species as well as the products of fusion (alpha particles). Calculations have shown that accounting for the content of thermalized reaction products (alpha particles) leads to an increase in radiation losses and a decrease in gain to <i>Q</i> < 1. In the steady-state scenario, the energy gain <i>Q</i>~5–10 can be obtained in p–¹¹B plasma, if only the fast (high-energy) population of fusion alpha particles is considered. For pulsed modes, the gain value is proportional to the content of alpha particles, and it is limited by the complete burn of one of the fuel components (boron), so it does not exceed unity. In the analysis we did not rely on any assumptions about the theoretically predicted mechanisms for increasing the cross section and the reaction rate, and only radiation losses (primarily bremsstrahlung) dramatically affect the gain <i>Q</i>. Thus, the regimes found can be considered as limiting in the framework of the classical concepts of processes in hot fusion plasma.

Utku K. Ercan, Adam D. Yost, Kimberly Wasko et al.

Intravenous catheter-related bloodstream infections are a cause of remarkable problems. Catheter lock solutions are used to keep catheter patency and prevent catheter-related bloodstream infections. The leakage of catheter lock solution to the bloodstream raises toxicity concerns. Plasma-treated liquids carry the potential to act as catheter lock solutions by virtue of their strong antimicrobial effects. The present study investigates the tolerance of the proposed solution in vitro and in vivo. <i>N</i>-acetylcysteine (NAC) solution was treated with atmospheric-air DBD plasma and antimicrobial assays were performed. The cytotoxicity of the plasma-treated NAC solution was evaluated on an EA.hy926 cell line. Intravenous administration of plasma-treated NAC solution in different doses was given to Sprague Dawley rats. One week after infusion with plasma-treated NAC solution, first, the blood samples were collected, and then liver, kidney, tail vein, heart, and lung tissue samples were collected from euthanized rats for histopathological examination. The cytotoxicity of plasma-treated NAC solution depended on plasma treatment time, contact time, and cell number. A strong antimicrobial effect with no cytotoxicity of plasma-treated NAC solution was observed in endothelial cells. Based on blood tests and histopathological examination, no signs of systemic toxicity were observed that can be correlated to the plasma-treated-NAC solution. This solution has the potential to be used as a catheter lock solution with strong antimicrobial properties, keeping catheter patency.

Masaomi Sanekata, Hiroshi Nishida, Tatsuya Watabe et al.

Delayed discharges due to electrical breakdown are observed in modulated pulsed pow er magnetron sputtering (MPPMS) plasma of titanium. The delayed discharge, which is remarkable with decreasing argon gas pressure, transforms the discharge current waveform from a standard modulated pulsed discharge current waveform to a <i>comb-like</i> discharge current waveform consisting of several pulses with high power. In addition, the delay times, consisting of statistical times and formative times in the delayed MPPMS discharges, are experimentally measured with the help of Laue plot analysis. The pressure dependence of delay times observed indicates that the delayed discharge behavior matches the breakdown characteristics well. In the present study, the delayed discharge dynamics of the <i>comb-like</i> discharge current waveform, which can be the origin of deep oscillation magnetron sputtering, are investigated based on measurement of the delay times and the characteristics of discharge current waveforms.

William A. Angermeier, Thomas G. White

Wave packet molecular dynamics (WPMD) has recently received a lot of attention as a computationally fast tool with which to study dynamical processes in warm dense matter beyond the Born–Oppenheimer approximation. These techniques, typically, employ many approximations to achieve computational efficiency while implementing semi-empirical scaling parameters to retain accuracy. We investigated three of the main approximations ubiquitous to WPMD: a restricted basis set, approximations to exchange, and the lack of correlation. We examined each of these approximations in regard to atomic and molecular hydrogen in addition to a dense hydrogen plasma. We found that the biggest improvement to WPMD comes from combining a two-Gaussian basis with a semi-empirical correction based on the valence-bond wave function. A single parameter scales this correction to match experimental pressures of dense hydrogen. Ultimately, we found that semi-empirical scaling parameters are necessary to correct for the main approximations in WPMD. However, reducing the scaling parameters for more ab-initio terms gives more accurate results and displays the underlying physics more readily.

Mounir Laroussi

This paper reviews the principles behind the design and operation of the resistive barrier discharge, a low temperature plasma source that operates at atmospheric pressure. One of the advantages of this plasma source is that it can be operated using either DC or AC high voltages. Plasma generated by the resistive barrier discharge has been used to efficiently inactivate pathogenic microorganisms and to destroy cancer cells. These biomedical applications of low temperature plasma are of great interest because in recent times bacteria developed increased resistance to antibiotics and because present cancer therapies often are accompanied by serious side effects. Low temperature plasma, such the one generated by the resistive barrier discharge, is a technology that can help overcome these healthcare challenges.

Nikolay A. Dyatko, Yury Z. Ionikh, Anatoly P. Napartovich

The present paper is based on the materials of the Invited Lecture presented at 29th Summer School and International Symposium on the Physics of Ionized Gases (28 August 2018&ndash;1 September 2018, Belgrade, Serbia). In the paper, the effect of nitrogen admixture on various characteristics of a dc glow discharge in argon (the volt-ampere characteristic, rate of plasma decay in the afterglow, discharge constriction condition, and formation of a partially constricted discharge) is considered.