{"title":"Physicochemical properties and antimicrobial efficacy of argon cold atmospheric pressure plasma jet activated liquids – a comparative study","authors":"Sarthak Das , Sarita Mohapatra , Satyananda Kar","doi":"10.1016/j.fpp.2024.100078","DOIUrl":"10.1016/j.fpp.2024.100078","url":null,"abstract":"<div><div>Cold atmospheric pressure plasma jet activated liquids (CAPJALs) have attracted considerable scientific attention due to their peculiar antimicrobial characteristics. In the current context, there is a need to compare the bactericidal activity of CAPJALs and demonstrate the specific parameters necessary to obtain greater effectiveness. This in-vitro research examines the antimicrobial activity of liquids, such as deionized water (DI-W), drinking water (DW), tap water (TW), and normal saline (NS) activated by Ar cold atmospheric pressure plasma jet (CAPJ) against multidrug-resistant (MDR) <em>E. coli</em> and <em>S. aureus</em>. The computed <em>D-</em> value showed that CAPJALs' bacterial inactivation efficacy followed the trend – DI-W ≈ NS > DW > TW for both the isolates. To obtain greater bactericidal effectiveness, an optimum combination of liquid activation time by CAPJ and CAPJAL – bacteria interaction time was noticed. In addition, the rate at which the physicochemical parameters (pH, electrical conductivity (EC), total dissolved solids (TDS), and concentration of reactive species (H<sub>2</sub>O<sub>2</sub>, NO<sub>3</sub><sup>-</sup>, and NO<sub>2</sub><sup>-</sup>)) changed within the liquid varied in different ways. It was observed that the identified gas-phase species (Ar I, Ar<sup>+</sup>, N<sub>2</sub>, N<sub>2</sub><sup>+</sup>, O I, OH•, OH<sup>+</sup>, NO<sup>+</sup>, O<sub>2</sub><sup>+</sup>, N<sub>2</sub>O<sub>3</sub><sup>-</sup>, NO<sub>3</sub><sup>-</sup>, N<sub>2</sub>O<sub>2</sub><sup>-</sup>, etc.) would contribute to modification of liquid physicochemical property by generating liquid phase reactive species (NO<sub>3</sub><sup>-</sup>, NO<sub>2</sub><sup>-</sup>, H<sup>+</sup>, H<sub>2</sub>O<sub>2</sub>, ONOOH, Cl<sub>2</sub>, HOCl, etc.) via reaction cascades. These reactive species in the liquid phase, together with other physicochemical characteristics, were found to play a part in the process of bacterial inactivation. This study into the underlying mechanism of CAPJ – liquid and CAPJAL – bacteria interaction would help to determine its potential use as a disinfectant in healthcare settings.</div></div><div><h3>List of microorganisms</h3><div><em>E. coli: Escherichia coli; S. aureus: Staphylococcus aureus</em>.</div></div>","PeriodicalId":100558,"journal":{"name":"Fundamental Plasma Physics","volume":"12 ","pages":"Article 100078"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Spectral line broadening of the Raman scattered waves in laser plasmas","authors":"Martin Mašek","doi":"10.1016/j.fpp.2024.100074","DOIUrl":"10.1016/j.fpp.2024.100074","url":null,"abstract":"<div><div>Parametric instabilities are of a great concern especially in the context of laser fusion. Electromagnetic waves scattered by these instabilities can reach high amplitudes, thereby diverting a significant portion of the energy from the incident laser beam, which is essential for compressing and heating the fuel capsule. In addition, the emerging electrostatic wave can trap and accelerate electrons, which, upon impact, can preheat the target and thus prevent its effective compression. Here, we focus on the stimulated Raman scattering and the associated processes. Spectral broadening of the backward Raman scattering daughter wave is theoretically described process, which is caused by so-called trapped particle instability. The existence of trapped and freely moving electrons in plasma influenced by high amplitude electron plasma wave leads also to the anomalous dispersion of this wave. It is reflected in the shifts in the electrostatic spectrum which, on the other hand, must be visible also in the electromagnetic spectrum via the feed-back loop of the instability. In the present paper, we discuss scattered wave modes spectral broadening using results of numerical simulations.</div></div>","PeriodicalId":100558,"journal":{"name":"Fundamental Plasma Physics","volume":"12 ","pages":"Article 100074"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142428158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Surface modification of fibres using bipolar pulsed driven DBD plasma based KrCl* and XeI* exciplex sources","authors":"Kiran Ahlawat, Vigyan Gadodia, Pooja Yadav, Ramavtar Jangra, Ram Prakash","doi":"10.1016/j.fpp.2024.100068","DOIUrl":"10.1016/j.fpp.2024.100068","url":null,"abstract":"<div><p>This work demonstrates the application of DBD plasma-based exciplex UV technology for surface modification of natural fibres. KrCl* (222 nm) and XeI* (253 nm) exciplex lamps have been developed and characterized in terms of the applied voltage, applied frequency, gas pressure, and absolute UV light intensity. The measured radiated intensities are 2.45 mW/cm<sup>2</sup> and 1.91 mW/cm<sup>2</sup> for 222 nm and 253 nm exciplex lamps, respectively. The change in physicochemical properties such as tensile strength, weight loss, wettability, surface morphology, and chemical composition, are evaluated using different characterization techniques ̶ like Contact Angle Goniometry, Thermogravimetric Analysis (TGA), Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Field Emission Scanning Electron Microscopy (FE-SEM), and Energy Dispersive X-ray (EDX) analysis, etc. The results are compared with untreated fibres to see the effect of different doses of UV<sub>222</sub> and UV<sub>253</sub> on the different properties of fibres. It is inferred that the exciplex UV<sub>222</sub> treated fibres have a higher concentration of different polar groups (− OH, − COOH, etc.). Much improvement in the dyebath ability of the natural fibre is achieved using a 222 nm exciplex light source, which reduces the dye concentration in the textile effluents and improves the dye adhesion to the fibre. It has been found that the fibre's hydrophilicity and dye bath capabilities have improved significantly.</p></div>","PeriodicalId":100558,"journal":{"name":"Fundamental Plasma Physics","volume":"12 ","pages":"Article 100068"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772828524000335/pdfft?md5=ceb8d004ad2b6af15e9c07cef1190582&pid=1-s2.0-S2772828524000335-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142088567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Chaos, periodicity, and multistability in a plasma oscillator forced by a non-sinusoidal wave function","authors":"Julio C. Sagás, Abel A.C. Recco, Paulo C. Rech","doi":"10.1016/j.fpp.2024.100072","DOIUrl":"10.1016/j.fpp.2024.100072","url":null,"abstract":"<div><p>In this paper we report on the dynamics of a plasma oscillator forced by a non-sinusoidal wave function, which is modeled by a six-parameter nonhomogeneous second-order ordinary differential equation. We keep four of these parameters constant, and investigate the dynamics of this system by varying other two parameters, namely <span><math><mi>A</mi></math></span> and <span><math><mi>ω</mi></math></span>, which are related to the amplitude and the angular frequency of the components of a Fourier series consisting of an expansion of cosine functions, that represents the external forcing. We investigate points in the two-dimensional <span><math><mrow><mo>(</mo><mi>ω</mi><mo>,</mo><mi>A</mi><mo>)</mo></mrow></math></span> parameter-space of the forced plasma oscillator, with the dynamical behavior of each these points being characterized as regular or chaotic, depending on the magnitude of the largest Lyapunov exponent. Then we show that this parameter-space reveals regions of occurrence of the multistability phenomenon in the system. Properly generated bifurcation diagrams confirm this finding. Basins of attraction of coexisting periodic and chaotic attractors in the phase-space are presented, as well as the coexisting attractors themselves.</p></div>","PeriodicalId":100558,"journal":{"name":"Fundamental Plasma Physics","volume":"12 ","pages":"Article 100072"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772828524000372/pdfft?md5=cd4b4062654f1b4f08fc7c9c4f1f98b4&pid=1-s2.0-S2772828524000372-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142164741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Magneto-inertial range dominated by magnetic helicity in space plasmas","authors":"Alexander Bershadskii","doi":"10.1016/j.fpp.2024.100066","DOIUrl":"https://doi.org/10.1016/j.fpp.2024.100066","url":null,"abstract":"<div><p>Magneto-inertial range dominated by magnetic helicity has been studied using results of the numerical simulations, laboratory measurements, solar, solar wind, and the Earth’s and planets’ magnetosphere observations (spacecraft measurements). The spectral data have been compared with the theoretical results based on the distributed chaos notion in the frames of the Kolmogorov–Iroshnikov phenomenology. The transition from magnetohydrodynamics to kinetics in the electron and Hall magnetohydrodynamics, and in a fully kinetic 3D approach, as well as in the solar wind, solar photosphere, and at the special events (reconnections, Kelvin–Helmholtz instability, isolated flux tube interchanges, etc.) in the magnetosphere of Earth, Saturn, Jupiter, and Mercury has been also discussed.</p></div>","PeriodicalId":100558,"journal":{"name":"Fundamental Plasma Physics","volume":"11 ","pages":"Article 100066"},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772828524000311/pdfft?md5=6e3ff431df9fec0fc9d94dcd75179ac9&pid=1-s2.0-S2772828524000311-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141480513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Comprehensive study of Kinetic Trajectory Simulation method for multi-component magnetized plasma-wall interaction process","authors":"Suresh Basnet , Roshan Chalise , Num Prasad Acharya , Raju Khanal","doi":"10.1016/j.fpp.2024.100067","DOIUrl":"10.1016/j.fpp.2024.100067","url":null,"abstract":"<div><p>For a wide range of plasma applications across diverse fields, a comprehensive understanding of the plasma-wall interaction mechanism is indispensable due to its inherent connection with confined plasma. This work compilation delves into the Kinetic Trajectory Simulation (KTS) method for the interaction of multi-component magnetized plasma with wall, specifically focusing on its implications for the tungsten wall sputtering model. In the evolution of the 1d3v (one dimensional spatial coordinates and three dimensional velocity coordinates) KTS method, the coupled set of kinetic equations has been solved under specified boundary conditions which yields results of higher accuracy. At the particle injection boundary, we have assumed the velocity distribution function of particle species to be cut-off Maxwellians, meeting essential requirements for plasma-wall transition processes: quasineutrality, sheath edge singularity, continuity of macroscopic fluid variables, and the kinetic Bohm sheath condition. The kinetic Bohm sheath condition, a fundamental criterion for plasma sheath formation, is extended for multi-component plasmas, accounting for the cut-off Maxwellian distribution of negatively charged particles. A comparative study of the kinetic Bohm sheath condition for cut-off and Boltzmann distributions reveals a deviation of less than 2.0% in magnitude. The concentration ratio of positive or negative ion species and the presheath side electron temperature influence various plasma-wall transition characteristics, including wall potential, Debye sheath thickness, particle densities, potential distribution, particle fluxes towards the surface, particle drift velocity, phase-space trajectory evolution, and physical sputtering of the tungsten surface. Although lighter ions possess higher energy when striking the surface, the physical sputtering yield of the tungsten surface is greater for heavier ions due to their lower threshold energy and larger collision cross-section. Furthermore, a comparative study of plasma-wall transition properties using kinetic and fluid approaches demonstrates qualitative similarities, with a notable deviation of approximately 4.0% in the magnitude in the vicinity of the material surface.</p></div>","PeriodicalId":100558,"journal":{"name":"Fundamental Plasma Physics","volume":"11 ","pages":"Article 100067"},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772828524000323/pdfft?md5=f4d1e366f9ae9c5c2d28bdc33e86d321&pid=1-s2.0-S2772828524000323-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141963478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Exact spherical vortex-type equilibrium flows in fluids and plasmas","authors":"Jason M. Keller, Alexei F. Cheviakov","doi":"10.1016/j.fpp.2024.100063","DOIUrl":"10.1016/j.fpp.2024.100063","url":null,"abstract":"<div><p>The famous Hill’s solution describing a spherical vortex with nested toroidal pressure surfaces, bounded by a sphere, propelling itself in an ideal Eulerian fluid, is re-derived using Galilei symmetry and the Bragg–Hawthorne equations in spherical coordinates. The correspondence between equilibrium Euler equations of fluid dynamics and static magnetohydrodynamic equations is used to derive a generalized vortex type solution that corresponds to dynamic fluid equilibria and static plasma equilibria with a nonzero azimuthal vector field component, satisfying physical boundary conditions. Separation of variables in Bragg–Hawthorne equation in spherical coordinates is used to construct further new fluid and plasma equilibria with nested toroidal flux surfaces, featuring respectively boundary vorticity sheets and current sheets. Finally, the instability of the original Hill’s vortex with respect to certain radial perturbations of the spherical flux surface is proven analytically and illustrated numerically.</p></div>","PeriodicalId":100558,"journal":{"name":"Fundamental Plasma Physics","volume":"11 ","pages":"Article 100063"},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772828524000281/pdfft?md5=48286a2083b13c041ea1a8a771cfbc8e&pid=1-s2.0-S2772828524000281-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141281043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Star formation across cosmic time","authors":"Jonathan Freundlich","doi":"10.1016/j.fpp.2024.100059","DOIUrl":"10.1016/j.fpp.2024.100059","url":null,"abstract":"<div><p>The interstellar medium of galaxies is composed of multiple phases, including molecular, atomic, and ionized gas, as well as dust. Stars are formed within this medium from cold molecular gas clouds, which collapse due to their gravitational attraction. Throughout their life, stars emit strong radiation fields and stellar winds, and they can also explode as supernovae at the end of their life. These processes contribute to stirring the turbulent interstellar medium and regulate star formation by heating up, ionizing, and expelling part of the gas. However, star formation does not proceed uniformly throughout the history of the Universe and decrease by an order of magnitude in the last ten billion years. To understand this winding-down of star formation and assess possible variations in the efficiency of star formation, it is crucial to probe the molecular gas reservoirs from which stars are formed. In this article following my presentation at the 10th International Conference on Frontiers of Plasma Physics and Technology held in Kathmandu from 13–17 March 2023, I review some aspects of the multiphase interstellar medium and star formation, with an emphasis on the interplay between neutral and ionized phases, and present recent and ongoing observations of the molecular gas content in typical star-forming galaxies across cosmic time and in different environments. I also present some of our understanding of star-forming galaxies from theoretical models and simulations.</p></div>","PeriodicalId":100558,"journal":{"name":"Fundamental Plasma Physics","volume":"11 ","pages":"Article 100059"},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772828524000244/pdfft?md5=f61269f2a2c88f17fb56be04dcb9479c&pid=1-s2.0-S2772828524000244-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141143542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}