Effect Of Plasma Parameters Research Articles

Low-temperature plasma jet suppresses bacterial colonisation and affects wound healing through reactive species.

An argon-based low-temperature plasma jet (LTPJ) was used to treat chronically infected wounds in Staphylococcus aureus-laden mice. Based on physicochemical property analysis and in vitro antibacterial experiments, the effects of plasma parameters on the reactive nitrogen and oxygen species (RNOS) content and antibacterial capacity were determined, and the optimal treatment parameters were determined to be 4 standard litre per minute and 35 W. Additionally, the plasma-treated activation solution had a bactericidal effect. Although RNOS are related to the antimicrobial effect of plasma, excess RNOS may be detrimental to wound remodelling. In vivo studies demonstrated that medium-dose LTPJ promoted MMP-9 expression and inhibited bacterial growth during the early stages of healing. Moreover, LTPJ increased collagen deposition, reduced inflammation, and restored blood vessel density and TGF-β levels to normal in the later stages of wound healing. Therefore, when treating chronically infected wounds with LTPJ, selecting the medium dose of plasma is more advantageous for wound recovery. Overall, our study demonstrated that low-temperature plasma jets may be a potential tool for the treatment of chronically infected wounds.

Effect of nonthermal and nonextensive electrons on dust acoustic waves in planetary rings

AbstractDust acoustic waves (DAWs) in plasmas are influenced by many plasma parameters, such as, ion temperature, electron number density, nonthermal and nonextensive parameters, and dust cyclotron frequency. The plasma system is described by plasma fluid equations. The Zakharov–Kuznetsov equation and instability growth rate of DAWs have been obtained by reductive perturbation method and small‐ expansion method, respectively. The effects of plasma parameters on the linear dispersion relation, phase velocity, amplitude, width, soliton energy, and three‐dimensional instability of DAWs have been carried out. It is obvious that the incremental nonextensive (nonthermal) parameter leads to the shrinking (incremental) soliton energy and phase velocity. These results are useful for understanding dusty plasma dynamics with Cairns–Tsallis electrons in planetary rings.

Electron beam driven ion-acoustic solitary waves in plasmas with two kappa-distributed electrons

Formation and the basic features of arbitrary amplitude ion-acoustic solitary waves (IASWs) in a plasma consisting of warm positive ions, two kappa-distributed electrons and an electron beam are investigated by using the Sagdeev pseudopotential approach. It is shown that the soliton existence domain (Mach number limits) sensitively depends on temperature of ions, spectral index of cool electrons and concentration of hot electron species while spectral index of hot electrons, hot-to-cool electron temperature ratio and also concentration of electron beam do not considerably affect this domain. It is also found that temperature of electron beam only affect the existence domain of rarefactive solitons. Furthermore, it is shown that considered plasma medium supports the coexistence of positive and negative IASWs. Moreover, effect of different plasma parameters such as hot-to-cool electron density ratio, ion-to-cool electron temperature ratio, beam-to-ion density ratio, hot-to-cool electron temperature ratio and superthermality index of electron species on the basic features of positive and negative IASWs is investigated numerically. Finally, the effect of plasma parameters on the parametric regime of coexistence of compressive and rarefactive IASWs is studied and, for example, effect of temperature of positive ions and number density of hot electrons on polarity of IASWs is numerically investigated.

Transitional properties of nonlinear traveling waves at the transcritical bifurcation point in a plasma with positive–negative ions

The bifurcation types and transitional properties of nonlinear ion-acoustic traveling waves have been explored in detail for a complex plasma with positive-negative ions and nonthermal electrons. The existence domain of stationary points and bifurcation responses are investigated on the fixed points-negative ion density plane. It is shown that both mass ratio of the positive to negative ions and the negative ion concentration play a pivotal role in the occurrence of bifurcations and transition between nonlinear waves. Under certain circumstances, we show that multi-ion plasma system admits transcritical bifurcation preceding the onset of saddle-node bifurcation. It is found that a sudden emergence of spike-like wave and transition between solitary and periodic waves occur at the critical point of transcritical bifurcation. The effects of plasma parameters on the bifurcation regions and the onset of transition between solitary waves and nonlinear periodic waves are investigated. We also show a novel kind of solitary structure at the bifurcation point with fatter tails compared to regular solitons. The present model is used to investigate the dynamical behavior of ion-acoustic waves in the () and () plasmas which are found in the D- and F-regions of the Earth's ionosphere, and also in the () experimental plasma.

Dissipative solitons in magnetized anisotropic plasma

The propagation of ion-acoustic (IA) dissipative solitons (DSs) is investigated in magnetized plasma with the presence of pressure anisotropy and Maxwellian distributed electrons. A nonlinear damped Korteweg-de Vries (d-KdV) type equation is derived for the potential by employing the reductive perturbation method (RPM) and its dissipative soliton solution is analyzed. The effect of plasma parameters like parallel anisotropic ion pressure p 1, perpendicular anisotropic ion pressure p 2, obliqueness l 3, ion-neutral collisional parameter γ and magnetic field strength Ω on the characteristics of DSs are investigated. The present investigation could be useful in space and astrophysical plasma systems.

Effect of electron density gradient on power absorption during gigahertz electromagnetic wave propagating in cold plasma

Considering the effect of electron density gradient, an analytical, parameter adjustable density distribution function is presented, and a multislab plasma model is used to investigate power absorption of gigahertz electromagnetic waves between 0.20 and 30 GHz in a partially ionized cold plasma layer. The effects of plasma parameters on the absorbed power during electromagnetic wave propagation are investigated and compared with corresponding uniform cases. An optimized asymmetric electron density gradient profile is designed by calculating the corresponding absorption spectrum with selected parameters to enhance the absorption rate near original peak frequencies. The possibility of theoretically designing electron density gradient profiles is important to understand how to enhance the plasma cloaking in some specific electromagnetic wave frequency bands.

Electron-Acoustic (Un)Modulated Structures in a Plasma Having (r, q)-Distributed Electrons: Solitons, Super Rogue Waves, and Breathers

The propagation of electron-acoustic waves (EAWs) in an unmagnetized plasma, comprising (r,q)-distributed hot electrons, cold inertial electrons, and stationary positive ions, is investigated. Both the unmodulated and modulated EAWs, such as solitary waves, rogue waves (RWs), and breathers are discussed. The Sagdeev potential approach is employed to determine the existence domain of electron acoustic solitary structures and study the perfectly symmetric planar nonlinear unmodulated structures. Moreover, the nonlinear Schrödinger equation (NLSE) is derived and its modulated solutions, including first order RWs (Peregrine soliton), higher-order RWs (super RWs), and breathers (Akhmediev breathers and Kuznetsov–Ma soliton) are presented. The effects of plasma parameters and, in particular, the effects of spectral indices r and q, of distribution functions on the characteristics of both unmodulated and modulated EAWs, are examined in detail. In a limited cases, the (r,q) distribution is compared with Maxwellian and kappa distributions. The present investigation may be beneficial to comprehend and predict the modulated and unmodulated electron acoustic structures in laboratory and space plasmas.

Developing Super-Hydrophobic and Abrasion-Resistant Wool Fabrics Using Low-Pressure Hexafluoroethane Plasma Treatment.

The growing interest in wool fibres as an eco-friendly and sustainable material for diverse industrial applications requires an enhancement of their functional performance. To address this, wool fabrics were treated in the present research with low-pressure hexafluoroethane (C2F6) plasma to impart superhydrophobicity and improve their abrasion resistance. Unscoured and scoured wool fabrics were treated with C2F6 while varying plasma power (80 W and 150 W), gas flow rate (12 sccm and 50 sccm) and treatment time (6 min and 20 min), and the effect of plasma parameters on the abrasion resistance, water contact angle and dyeing behaviour of the wool fabrics was studied. Martindale abrasion testing showed that the surface abrasion of the wool fabrics increased with the number of abrasion cycles, and the samples treated with 150 W, 20 min, 12 sccm showed superior abrasion resistance. The scoured wool fabrics showed a contact angle of ~124°, which was stable for only 4 min 40 s, whereas the plasma-treated samples showed a stable contact angle of over 150°, exhibiting a stable superhydrophobic behaviour. The C2F6 plasma treatment also significantly reduced the exhaustion of an acid dye by wool fabrics. The EDX study confirmed the deposition of fluorine-containing elements on the wool fabrics significantly altering their properties.

Nonlinear periodic structures in a magnetized plasma with Cairns distributed electrons

The electrostatic ion acoustic (IA) nonlinear periodic (cnoidal) waves are studied in a magnetized plasma comprising of cold ions and Cairns distributed electrons. By employing reductive perturbation technique (RPT), the nonlinear Korteweg-de Vries (KdV) and modified KdV (mKdV) equations are derived, and their cnoidal wave (CW) solutions are obtained. For a given set of plasma parameters, the present model supports both compressive and rarefactive nonlinear periodic structures. In the present work, the effects of plasma parameters like nonthermality of electrons ( $$\beta $$ ) and obliqueness ( $$ l_{z} $$ ) are investigated. It is found that increasing values of $$\beta $$ and $$l_{z}$$ lead to enhancement (reduction) in amplitude of IA compressive (rarefactive) nonlinear periodic structures. Our present study has some relevance to the CW structures observed in magnetosphere via POLAR and FAST spacecrafts.

Enhanced Wetting and Adhesive Properties by Atmospheric Pressure Plasma Surface Treatment Methods and Investigation Processes on the Influencing Parameters on HIPS Polymer

The development of bonding technology and coating technologies require the use of modern materials and topologies for the demanding effect and modification of their wetting properties. For the industry, a process modification process that can be integrated into a process is the atmospheric pressure of air operation plasma surface treatment. This can be classified and evaluated based on the wettability, which has a significant impact on the adhesive force. The aim is to improve the wetting properties and to find the relationship between plasma treatment parameters, wetting, and adhesion. High Impact PolyStyrene (HIPS) was used as an experimental material, and then the plasma treatment can be treated with various adjustable parameters. The effect of plasma parameters on surface roughness, wetting contact angle, and using Fowkes theory of the surface energy have been investigated. Seven different plasma jet treatment distances were tested, combined with 5 scan speeds. Samples with the best plasma parameters were prepared from 25 mm × 25 mm overlapping adhesive joints using acrylic/cyanoacrylate. The possibility of creating a completely hydrophilic surface was achieved, where the untreated wetting edge angle decreased from 88.2° to 0° for distilled water and from 62.7° to 0° in the case of ethylene glycol. The bonding strength of High Impact PolyStyrene was increased by plasma treatment by 297%.

Effect of streaming velocity, magnetic field, and higher-order correction on the nature of ion acoustic solitons in the Venusian ionosphere

Propagation properties of weakly nonlinear ion acoustic waves are investigated in a plasma at the Venusian ionosphere. The plasma model consists of two positive cold ions (oxygen O + and hydrogen H +), as well as isothermal electrons. The basic set of fluid equations is reduced to Zakharov-Kuznetsov (ZK) equation and linear inhomogeneous ZK-type equation (LIZKT) equation. The renormalization method is adopted to obtain solitary solutions of both equations. The effects of plasma parameters and higher-order correction on the nature of the solitary waves are investigated. It is found that the wave phase velocity is supersonic, which is in agreement with the observations. Furthermore, the higher-order correction enlarges the soliton amplitude, which is suitable for describing the solitary waves when the wave amplitude grows.

Overtaking Collisions of Ion Acoustic N-Shocks in a Collisionless Plasma with Pair-Ion and (α,q) Distribution Function for Electrons

In this work, the effects of plasma parameters on overtaking collisions of ion acoustic multi-shocks are studied in an unmagnetized collisionless plasma with positive and negative ions, and (α,q)-distributed electrons. To investigate such phenomena, the reductive perturbation technique is implemented to derive the Burgers equation. The N-shock wave solution is determined for this equation by directly implementing the exponential function. The result reveals that both the amplitudes and thicknesses of overtaking collisions of N-shock wave compressive and rarefactive electrostatic potential are significantly modified with the influences of viscosity coefficients of positive and negative ions. In addition, the density ratios also play an essential role to the formation of overtaking collisions of N-shocks. It is observed from all theoretical and parametric investigations that the outcomes may be very useful in understanding the dynamical behavior of overtaking collisions of multi-shocks in various environments, especially the D- and F-regions of the Earth’s ionosphere and the future experimental investigations in Q-machine laboratory plasmas.

Deuterium analysis by inductively coupled plasma mass spectrometry using polyatomic species: An experimental study supported by plasma chemistry modeling

A new analytical method is proposed for the determination of deuterium (D) by ICP-MS. The method is based on the use of the signal from hydrogen-containing polyatomic ions formed in the inductively coupled plasma. Prior to analytical experiments, a theoretical study was performed to assess the concentration of polyatomic species present in an equilibrium Ar-O-D-H plasma, as a function of temperature and stoichiometric composition. It was established that the highest sensitivity and linearity measurement of D concentration in a wide range can be achieved by monitoring the ions of D2 and ArD, at masses 4 and 42, respectively. Results of the calculations are in good agreement with the experiments. Signal stability, spectral interferences, as well as the effect of plasma parameters were also assessed. Under optimized conditions, the limit of detection (LOD) was found to be 3 ppm atom fraction for deuterium when measured as ArD (in calcium and potassium free water), or 78 ppm when measured as D2. The achieved LOD values and the 4 to 5 orders of magnitude dynamic range easily allow the measurement of deuterium concentrations at around or above the natural level, up to nearly 100% (or 1 Mio ppm) in a standard quadrupole ICP-MS instrument. An even better performance is expected from the method in high resolution ICP-MS instruments equipped with low dead volume sample introduction systems.

Self-Oscillating Mode of a Probe with Increased Secondary Emission for Nonequilibrium Plasma Diagnostics

A method of ion saturation current measurement in a nonequilibrium plasma by a self-oscillating voltage sweep on the probe is described. The generation of voltage pulses is possible if a high secondary electron emission from the probe surface is ensured, significantly exceeding unity at a moderate negative potential. The theoretical basis of the self-oscillating probe method has been considered, which made it possible to describe the ways for controlling the repetition rate and pulse amplitude and the effect of plasma parameters on the shape of current and voltage signals. It is shown that the features of the phase trajectory of the signal from the probe on the (U, I) plane allow one to determine the reference points of instantaneous probe characteristic, in particular, the ion saturation current. The results of experiments on testing the self-oscillating probe technique, which were carried out using the PR-2 plasma-beam facility, are presented.

An investigation into the microstructure and tribological properties of rail materials with plasma selective quenching

Plasma selective quenching (PSQ) forms dispersed hardening microscopic structures on the rail material surface by the action of energetic plasma. In this study, the microstructure and tribological properties of PSQ treated rail materials are investigated by the rolling fatigue test and metallographic analysis. The effect of plasma parameters on the surface quality and microstructure is analyzed, and the optimum diameter of PSQ region is 5.0 mm. The microhardness in the PSQ region significantly increased and the tribological properties of rail materials improved. Meanwhile, severe spalling occurs on the surface in the PSQ region. Based on the field application, the wear resistance of the switch rails is enhanced by approximately 3 times that of untreated rail materials.

Head-on collision between single- and multi-soliton heavy ion acoustic waves in multi-ion plasmas

Head-on collisions among the single-and multi-soliton’s heavy ion acoustic waves (HIAWs) of multi-ion plasma are studied. The plasma consists of adiabatic positively charged inertial heavy ions, Boltzmann energy distributed light ions and kappa energy distributed electrons. The extended poincaré-Lighthill-Kuo (ePLK) method is applied for the derivation of two-sided Korteweg–de Vries (KdV) equations (KdVEs). The KdV single-soliton solutions (KdVSSs) are determined using the hyperbolic secant method and the KdV multi-soliton solutions (KdVMSs) are obtained using the Hirota method. The effects of superthermality of electrons, temperature ratios of electron to light ion and heavy ion to electron, and the density ratio of electron to heavy ion on phase shifts are investigated for the head-on collisions between two-soliton HIAWs. The effects of plasma parameters on angular frequency, phase speed, production of multi-soliton structures, and the head-on collisions among single-, double-, triple-, quadruple-, and quintuple-solitons are also studied.

Effect of plasma and beam parameters on focal dimensions in micrometer charged particle optics: Enhanced nonlinear demagnification below the Debye length

Detailed experiments and computer simulations employing two beam computational tools commonly used for benchmarking ion beam optics, AXCEL-INP and SIMION, are carried out to investigate the dependence of focal dimensions FD (length and image size) of ion beams extracted from a compact electromagnetic wave driven plasma source. The effect of plasma parameters, such as space potential VP, Bohm velocity vB, and the associated initial kinetic energy Ei, electron Te and ion temperatures Ti, ion mass M, ion current density Ji, and beam related parameters such as beam energy EB, plasma and beam limiter (BL) electrode aperture sizes, and potential applied to lenses (EL1 and EL2), on the FD are investigated. Variation of the focal length fl with vB, VP, and Ei indicates that fl increases with the increase in these parameters; however, it decreases with EB. fl is found to decrease with M and is independent of the BL aperture size; however, it is found to increase with extraction voltage V1 (EL1). Two different theoretical models to estimate the focal length of the combined lens system are developed, and the estimated values of fl are found to agree reasonably well with the experimental and simulation results. The sharpness of focus characterized by the beam angle at the focal point is determined for Ar, Kr, and Ne ion beams. A remarkable feature of nonlinear demagnification in plasma based beams is observed with significant enhancement when the plasma electrode aperture size is reduced to below the Debye length.

Obliquely propagating nonlinear ion-acoustic solitary and cnoidal waves in nonrelativistic magnetized pair-ion plasma with superthermal electrons

The nonlinear propagation of ion-acoustic waves is considered in a magnetized system of collisionless and dissipative pair-ion plasma, composed of cold positively and negatively charged nonrelativistic ions, with superthermal electrons. obliquely propagating ion-acoustic solitary and cnoidal waves are investigated via a mechanical-motion analog Korteweg de Vries (KdV) approach. The characteristics of the emerged nonlinear magnetized waves are significantly modified by the effects of plasma parameters like the obliquity angle, superthermality parameter, negative to positive ions density ratio, electron density and it is also affected by the electron temperature. The obtained results can be generalized to be used to investigate the plasma waves nature in neutron stars, Saturn’s and Pulsars magnetospheres in addition to the laboratory plasmas.

NTP-assisted partial oxidation of methane to methanol: effect of plasma parameters on glass-packed DBD

The partial oxidation of methane to methanol was performed in a non-thermal dielectric barrier discharge (DBD) plasma reactor. The influence of various parameters on the conversion of methane, product selectivity and energy efficiency has been studied. Typical results indicate that the discharge gap has a marked influence on methane conversion and product distribution. The best selectivity to CH3OH and HCHO was ~25% and ~17% at a discharge gap of 4.5 and 5 mm, respectively, and the highest corresponding energy efficiency was ~0.9 mmol kJ−1. At a later state, the DBD reactor was operated under a packed-bed configuration by integrating the discharge gap with zero surface glass materials having different geometry: glass beads (spherical), glass capillary (hollow cylindrical) and glass wool (spongy honeycomb) to understand the influence of material geometry on the plasma discharge and finally on the formation of products such as CH3OH, HCHO, CO, CO2, H2, C2H6. Typical results indicated that the morphology of the packing materials affects the discharge characteristics, and hence the product distribution. It is concluded that the better performance of the packed-bed plasma reactor is due to the improved electrical field strength. Among the geometries studied, glass wool showed the highest CH4 conversion due to the improved field strength/surface corona, whereas glass-bead packing improved the CH3OH selectivity to ~32%.

Solutions of nonplanar KP-equations for dusty plasma system with GE-method

The propagation of three-dimensional nonlinear dust acoustic waves in a dusty plasma consisting of positive and negative dust grains as well as Boltzmann distributed electrons and ions is investigated. Using a reductive perturbation method, Cylindrical Kadomtsev-Petviashvili and Spherical Kadomtsev-Petviashvili equations, appropriate for describing the evolution of the system, are derived. The Generalized Expansion method is used to find the various solutions of the obtained nonlinear Kadomtsev-Petviashvili equations. New classes of triangular, hyperbolic solitary, rational, and Jacobi elliptical type solutions are obtained and graphically presented. It is found that the proposed dusty plasma model can support solitary waves with compressive and rarefactive potential pulses. Moreover, the effects of plasma parameters on this solitary wave structure are investigated. The current findings are applied to a cosmic-type plasma in different regions of space, viz. cometary tails, mesosphere, and Jupiter's magnetosphere as well as laboratory-type plasma such as low temperature experiments, where a dusty plasma with opposite polarity is dominant.