Ion Mass Ratio Research Articles

Nonlinear analysis of ion‐acoustic solitary waves in an unmagnetized highly relativistic quantum plasma

AbstractThe present paper explores the dynamics of ion‐acoustic solitary waves (IASWs) within an unmagnetized, highly relativistic quantum plasma containing positive and negative ions alongside electrons, employing the quantum hydrodynamic model. The treatment accounts for the inertial characteristics of negative and positive ions, considering electrons as inertialess. The nonlinear nature of quantum IASWs is investigated through the derivation of the Korteweg–de Vries equation using the reductive perturbation method. The investigation highlights how wave propagation characteristics, whether compressive or rarefactive, are substantially modulated by several parameters, such as the quantum diffraction parameter , relativistic effects , equilibrium density , and ion mass ratio . The analysis identifies the existence of both slow and fast wave modes, heavily influenced by the relativistic parameters involved. Our findings have significant implications for the understanding of both laboratory and space plasmas, especially in contexts where negative ions are present.

Numerical Study of Pressure Response to Action Potential by Water Permeation With Ion Transports

Abstract While the permeation mechanism of solute (e.g., ions and glucose) through biological membrane has been studied extensively, the mechanical role of water transport in intracellular phenomena has not received much attention. In the present study, to investigate the effect of water permeation on the intracellular pressure response, a novel permeation flux model through a biological membrane is developed by incorporating the coupling permeabilities (between water and ion fluxes) as the water–ion interaction in the ion channels. The proposed model is applied to a two–dimensional permeation problem of water and ions in a closed cell separated by a thin membrane. The permeation flux model reproduces the typical time response of intracellular pressure to action potentials with reasonable agreement with experimental results in the literature, indicating that the pressure response can be characterized by the following three parameters: water permeability, the mass ratio of water and ion, and the ratio of the permeation fluxes of water and ion. In particular, the permeation flux ratio plays an essential role in intracellular phenomena; depending on the value of the permeation flux ratio, the time lag between the action potential and the pressure response is 0.1 times smaller than that expected by the previous researchers, indicating that water transport associated with ions may trigger a pressure response. This study demonstrates the importance of water permeation in intracellular mechanical response through coupling of the fluid motion and electric fields.

Landau damping effects on dust ion-acoustic solitary waves in a nonthermal pair-ion plasma

The Landau damping effects on the nonlinear propagation of dust ion-acoustic solitary waves (DIASWs) are studied in an electron-free unmagnetized collisionless dusty pair-ion plasma. The two species of nonthermal ions (positive and negative) are described by the kinetic Vlasov equations, whereas the massive charged dust grains form only the background plasma. Using the multi-scale reductive perturbation technique generalized for the applications to the Vlasov equation, we derive a modified Korteweg–de Vries (KdV) equation that governs the evolution of DIASWs with the effects of linear resonance, in particular, linear Landau damping. The properties of the phase velocity and the Landau damping rate of DIASWs are studied with the effects of positive and negative-ion nonthermality parameters ( α p , α n ), the ratios of the positive to negative ion masses (m) and temperatures (T) as well as the dust to negative-ion number density ratio (δ). It is found that, depend on the degree of positive to negative ion mass ratios (m), both of damped and growing oscillations occur in a collisionless dusty pair-ion plasma due to the resonance phenomena between the wave and the nonthermal particles of the system. The properties of the decay rates of the amplitude of the KdV soliton with a small effect of Landau damping are also studied with the above system of parameters. The results may be useful for understanding the localization of solitary pulses and associated resonance damping and/or growing oscillations of the wave in laboratory and space plasmas, in which the number density of free electrons is much smaller than that of ions and highly charged heavy, micron seized dust grains.

Fast correlation heating in moderately coupled electron–ion plasmas

If the electrons in a plasma are suddenly heated, the resulting change in Debye shielding causes the ion kinetic energy to quickly increase. For the first time, this correlation heating, which is much faster than collisional energy exchange, is rigorously derived for a moderately coupled, electron–ion plasma. The electron–ion mass ratio is taken to be the smallest parameter in the Bogoliubov–Born–Green–Kirkwood–Yvon hierarchy, smaller even than the reciprocal of the plasma parameter. This ordering differs from conventional kinetic theory by making the electron collision rates faster than the ion plasma frequency, which allows stronger coupling and makes the ion heating a function only of the total energy supplied to the electrons. The calculation uses known formulae for correlations in a two-temperature plasma, for which a new, elementary derivation is presented. Suprathermal ions may be created more rapidly by this mechanism than by ion–electron Coulomb collisions. This means that the use of a femtosecond laser pulse could potentially help to achieve ignition in certain fast ignition approaches to inertial confinement fusion.

Stability and bifurcation analysis of low‐frequency electrostatic waves in warm negative ion plasmas

AbstractIn this paper, we perform stability and bifurcation analysis of ion‐acoustic waves in a plasma consisting of warm adiabatic positive and negative ions, evolving against a uniform background of isothermal electrons. The model consists of two nonlinear ordinary differential equations incorporating ion temperature, negative ion concentration and negative‐to‐positive ion mass. We derive the normal form of bifurcation which allows the determination of travelling wave solutions for various regions in the parameter space of warm negative ion plasmas. It is shown that negative/positive ion temperature broadens the region prior to the saddle‐node bifurcation, thereby allowing the propagation of solitary and supernonlinear periodic waves. For a range of ion mass ratio and ion temperature, we find different existence domains of stability region, and examine the occurrence of transcritical bifurcation as a function of various plasma parameters. Further, we perform a numerical phase portrait analysis of the complex system including homoclinic orbits, nonlinear periodic and super nonlinear periodic orbits. The effects of ion mass ratio and ion temperature on the characteristic of these nonlinear structures are discussed in detail. Our results are relevant to wave solutions in laboratory and space plasmas, where simultaneous presence of warm negative/positive ions are observed.

Stratigraphic and structural controls on the occurrence of saline springs within the Illinois Basin, U.S.

Saline springs within intracratonic basins are a common, but rarely studied phenomena. Derived primarily from the mixing of basin brines (evaporated seawater) with shallow groundwater and/or freshwater recharge, there are many saline springs within the Illinois Basin. These include free-flowing springs, bedrock seeps into otherwise freshwater aquifers, and salt licks. In this study, a total of 44 saline springs, seeps, licks and wells were sampled. The chemical compositions of the saline springs of the Illinois Basin are dominated by Na and Cl- with a combined concentration as high as 60,000 mg/L. Some of the springs are enriched in H2S supporting populations of white filamentous, sulfide-oxidizing bacteria. Because the spring water contains a component of basin brines, and because basin brines of the Illinois Basin have been well characterized by others, ion mass ratios were used to identify the geologic period of the source formation(s).In general and on a basin-wide scale, saline groundwater discharge occurred along geologic structures and from strata along the margins of the Illinois Basin, originating from every period of the basin’s geologic strata (Cambrian through Pennsylvanian). The greatest number of saline springs occurred where geologic structures intersect large streams or major aquifers. Saline springs were often found in clusters that may extend over many square kilometers. The occurrence of saline springs are a reflection of the geology, geologic structure, geologic history including continental glaciation, surface water-groundwater interactions, groundwater flow regimes, and overall groundwater chemistry within the Illinois Basin. In parts of the Illinois Basin, our data suggest that brines within strata of older geologic periods have migrated upward along geologic structures, infiltrated strata of younger geologic periods, and mixed with, and in some cases, replaced brines within those strata. The source of salinity in springs within the center of the Illinois Basin is typically brines from geologic strata that outcrops and subcrops along structures associated with the LaSalle Anticlinorium. Salt licks that occur near the southeastern boundary of the Illinois Basin in Kentucky constitute points of discharge for regional groundwater flow from the basin. The Cl/Br and K/Cl mass ratios of the salt licks in Kentucky suggest that the saline groundwater is a mixture of brines from Cambrian and Ordovician strata.

Relaxation of strongly coupled binary ionic mixtures in the coupled mode regime

Understanding ion transport in plasma mixtures is essential for optimizing the energy balance in high-energy-density systems. In this paper, we focus on one transport property, ion–ion temperature relaxation in a strongly coupled plasma mixture. We review the physics of temperature relaxation and derive a general temperature relaxation equation that includes dynamical correlations. We demonstrate the fidelity of three popular kinetic models that include only static correlations by comparing them to data from molecular dynamics simulations. We verify the simulations by comparing with laboratory data from ultracold neutral plasmas. By comparing our simulations with high fidelity kinetic models, we reveal the importance of dynamical correlations in collisional relaxation processes. These correlations become increasingly significant as the ion mass ratio in a binary mixture approaches unity.

On the rate of energy deposition by an ion ring velocity beam

Using a novel three-dimensional electromagnetic hybrid code, XHYPERS, we simulate the generation of lower hybrid oscillations in a magnetized plasma by a heavy ion beam with a ring-shaped velocity distribution over much longer periods of time compared to previous simulations. We introduce a phenomenological (effective) electron damping to represent the induced scattering of lower-hybrid waves to whistlers and the loss of energy through whistler propagation out of the turbulent region. We demonstrate the effective electron damping to be a crucial factor in increasing the efficiency of energy deposition by an ion ring velocity beam into plasma turbulence and investigate the efficiency of beam energy extraction as a function of the electron damping rate and beam to plasma ion mass ratio.

Electron and positron nonthermality effects on the formation of damped solitons in collisional multi-component plasmas

Electrostatic damped field characteristics in non-thermal fast positron and electron plasma having fluids of positive and negative pair ions have been discussed when collisional frequencies parameters are taken into account. The damped and forced form of Kadomtsev-Petviashvili (DKP) equations have been obtained. The plasma parameters effects of electron density ratio, the negative ionic density ratio, the pair ionic charge ratio, the density of positron ratio, the collisional frequencies, ion mass ratio and the fast non-thermality on the electrostatic damped and forced field formations, as observed in D-F -ionosphere and laboratory experiments have been investigated.

Electrostatic wave breaking limit in a cold electronegative plasma with non-Maxwellian electrons

A one-dimensional multifluid hydrodynamic model has been adopted as basis for an investigation of the role of suprathermal electrons on the wave breaking amplitude limit for electrostatic excitations propagating in an electronegative plasma. A three-component plasma is considered, consisting of two inertial cold ion populations of opposite signs, evolving against a uniform background of (non-Maxwellian) electrons. A kappa-type (non-Maxwellian) distribution function is adopted for the electrons. By employing a traveling wave approximation, the first integral for the fluid-dynamical system has been derived, in the form of a pseudo-energy balance equation, and analyzed. The effect of intrinsic plasma parameters (namely the ion density ratio, the ion mass ratio, and the superthermal index of the nonthermal electrons) on the wave breaking amplitude limit is explored, by analyzing the phase space topology of the associated pseudopotential function. Our results are relevant to particle acceleration in Space environments and to recent experiments based on plasma-based accelerator schemes, where the simultaneous presence of negative ions and nonthermal electrons may be observed.

Particle-in-cell simulations of the Cassini spacecraft’s interaction with Saturn’s ionosphere during the Grand Finale

ABSTRACT A surprising and unexpected phenomenon observed during Cassini’s Grand Finale was the spacecraft charging to positive potentials in Saturn’s ionosphere. Here, the ionospheric plasma was depleted of free electrons with negatively charged ions and dust accumulating up to over 95 per cent of the negative charge density. To further understand the spacecraft–plasma interaction, we perform a three-dimensional Particle-In-Cell study of a model Cassini spacecraft immersed in plasma representative of Saturn’s ionosphere. The simulations reveal complex interaction features such as electron wings and a highly structured wake containing spacecraft-scale vortices. The results show how a large negative ion concentration combined with a large negative to positive ion mass ratio is able to drive the spacecraft to the observed positive potentials. Despite the high electron depletions, the electron properties are found as a significant controlling factor for the spacecraft potential together with the magnetic field orientation which induces a potential gradient directed across Cassini’s asymmetric body. This study reveals the global spacecraft interaction experienced by Cassini during the Grand Finale and how this is influenced by the unexpected negative ion and dust populations.

Dynamics of ion‐acoustic rogue waves in electron‐positron‐ion magneto‐plasmas

AbstractA more general and realistic four‐component magnetized plasma medium consisting of opposite polarity ions and nonthermal distributed positrons and electrons is considered to investigate the stable/unstable frequency regimes of modulated ion‐acoustic waves (IAWs) in the D‐F regions of Earth's ionosphere. A (3 + 1)‐dimensional nonlinear Schrödinger equation, which leads to the modulation instability (MI) of IAWs, is derived. The parametric regimes for the existence of the MI, first‐ and second‐order rogue waves, and also their basic features (viz., amplitude, width, and speed) are found to be significantly modified by the effect of physical plasma parameters and external magnetic field. It is found that the nonlinearity of the different types of electronegative plasma system depends on the positive to negative ion mass ratio. It is also shown that the presence of nonthermal distributed electrons and positrons modifies the nature of the MI of the modulated IAWs. The implication of our results for the laboratory plasma [e.g., (Ar+, F−) electronegative plasma] and space plasma [e.g., (H+, H−), () electronegative plasma in D‐F regions of Earth's ionosphere] are briefly discussed.

Stationary plasma configurations in a toroidal trap with D-shaped cross section in the two-fluid MHD approximation (Morozov–Soloviev equations)

In 1974, A.I. Morozov and L.S. Soloviev derived a general set of hydrodynamic equations for two-component ideal plasma under the stationary flow conditions, as applied to the plasma acceleration problems. Under the conditions of axial symmetry, the authors managed to reduce this very complex system to a more simple form by introducing three functions of the flux (the magnetic field flux, electron flux and ion flux). This situation is reminiscent of the one that develops when obtaining the Grad–Shafranov equation: the problem of static plasma equilibrium is reduced to solving one second-order equation for the magnetic field flux function. The rest condition for the two-component plasma is usually interpreted as the condition of vanishing the mass-average plasma velocity. This condition coincides with the condition of ion immobility up to a value of the order of the electron to ion mass ratio. In this work, the Morozov–Soloviev equations will be used for the first time to study the stationary plasma configurations in the toroidal magnetic trap with the D-shaped cross section. The geometric parameters of the trap correspond to those of the two currently operating tokamaks: the JET and the JT60U.

Dynamical properties of nonlinear ion-acoustic waves based on the nonlinear Schrödinger equation in a multi-pair nonextensive plasma

Abstract Dynamical properties of nonlinear ion-acoustic waves (IAWs) in multi-pair plasmas (MPPs) constituting adiabatic ion fluids of positive and negative charges, and q-nonextensive electrons and positrons are examined. The nonlinear Schrödinger equation (NLSE) is considered to study the dynamics of IAWs in a nonextensive MPP system. Bifurcation of the dynamical system obtained from the NLSE shows that the system supports various wave forms such as, nonlinear periodic wave, kink and anti-kink waves in different ranges of q. The analytical solutions for ion-acoustic nonlinear periodic wave, kink and anti-kink waves are obtained. The impacts of system parameters such as, nonextensive parameter (q), mass ratio of negative and positive ions (μ 1), number density ratio of positive and negative ions (μ 2), number density ratio of positrons and negative ions (μ p), temperature ratio of positive ions and electrons (σ 2) and temperature ratio of electrons and positrons (δ) on IAW solutions are bestowed. The results of this study are applicable to understand different dynamical behaviors of nonlinear IAWs found in the Earth’s ionosphere, such as, D-region [H+, O 2 − ${\mathrm{O}}_{2}^{-}$ ] and F-region [H+, H−] and multipair plasma system laboratory [C+, C−].

Adsorption and catalytic reduction of rifampicin in wastewaters using hybrid rGO@Fe/Pd nanoparticles

Ubiquitous use of antibiotics worldwide has resulted in their significant efflux into the environment impacting ecosystem health to such a degree that antibiotic removal has become a key environmental issue. Here one target antibiotic, rifampicin, was successfully removed from aqueous solution using a hybrid nanomaterial (rGO@Fe/Pd NP) having an adsorption capacity of 90.9 mg g−1. The factors influencing rifampicin removal by rGO@Fe/Pd NPs and each constituent component of the hybrid nanomaterial were also investigated. Adsorption and reduction kinetics indicated that rifampicin conformed to a pseudo-second-order model. While X-ray diffraction and Fourier transform infrared spectroscopy showed that rifampicin was adsorbed by rGO@Fe/Pd NPs, scanning electron microscopy and X-ray photoelectron spectroscopy showed that rifampicin was reduced by nano iron and during this process, nano palladium acted as a catalyst. Liquid chromatography-mass spectrometry, confirming that rifampicin was indeed catalytically degraded by rGO@Fe/Pd NPs, as evidenced by a decrease in ion mass ratio from 823.41 (M+1H) to 611.21 (M+1H) or 606.37 (M+1H). A mechanism for rifampicin degradation based on adsorption and catalytic reduction was proposed. In addition, the practical removal efficiency of rifampicin was successfully validated in aquaculture sewage water (71.9%) and for municipal sewage (58.1%). This article provides a strong scientific basis for the degradation mechanism of rifampicin by rGO@Fe/Pd NPs indicating that this hybrid material has great potential for practical applications.

Behaviour of sheath in electronegative warm plasma

Behaviour of sheath formed on two types of probes, namely cylindrical and spherical probes, has been investigated in terms of its thickness, in front of the conducting probes immersed in an electronegative plasma for different negative to positive ion mass ratios, by considering three electronegative gases, i.e. CF4, O2 and C60. Contrary to others’ work, complete fluid equations are written for negative ions also in addition to those of positive ions considering their different masses. Increasing negative to positive ion mass ratio is found to result in an increment of the sheath thickness. The magnitude of the sheath thickness is enhanced with an increment in the positive ions’ temperature, whereas the magnitude of the sheath thickness is reduced with increased negative ions’ temperature and background density of the negative ions. The analysis of the case of a large probe radius, used in the surface-nitriding process, for both the geometries is attended. Additionally, the comparison between the results for electropositive plasma and electronegative plasma and for behaviour of negative ions with their Boltzmann distribution and fluid approach has also been attempted herewith and a noteworthy difference is realized. The case of doubly charged ions is also entertained herewith.

The Role of Modified Boltzmann Relation With Electron Inertia on the Evolution of Solitary Waves Derived by Energy Integral Method Along With the Comparative Studies on Soliton Dynamics in Generalized Multi-Component Plasma

The nonlinear solitary waves in multi-component plasmas coexisting with negative ions, relativistic, and nonrelativistic electrons have been investigated under the influence of a modified Boltzmann relation with electron inertia $m_{\text {e}}$ (mass of electrons $\ne 0$ ) by Sagdeev potential and perturbation methods. The supersonic and subsonic compressive solitons are shown to be dependable on higher negative ion concentrations and the direction of wave propagation ( $k_{x} $ ). The condition of characteristic representation of the new Boltzmann relation appears to generate substantially high amplitude rarefactive solitons based on the direction of propagation, negative to positive ion mass ratio $r$ (>1), and high Mach number $M$ . The relativistic effects in non-Boltzmann electrons causing an increase in mass are responsible for the change in the growth of solitons in plasma.

Interaction phenomena of ion‐acoustic quasi‐solitons and classical‐solitons in three component plasma

The space–time evolution of the cnoidal‐soliton solution, characteristics of the quasi‐soliton solution of Korteweg‐de‐Vries (KdV) equation, and the interaction phenomena of ion‐acoustic waves (IAWs) are investigated in a plasma system consisting of positive and negative ions with superthermal electrons. To do this, and (Ar+, F−) plasmas are considered and two‐sided KdV equations (KdVEs) are derived applying the extended Poincaré‐Lighthill‐Kuo (ePLK) method. The effects on wave structures, potential profiles, and propagation characteristics with plasma parameters of the cnoidal‐wave, quasi‐soliton solution, and head‐on collision phenomena of IAWs are presented graphically. It was found that the superthermality parameter and the mass ratio of ions play a significant role in the head‐on collision between soliton and standing cnoidal wave and reveal that the collision is elastic and both waves change their phase shifts due to collision. Moreover, the superthermality parameters are also responsible for the production of compressive and rarefactive phase shifts in overtaking collision processes between right travelling classical soliton (CS) and cnoidal wave (CW) and reduced the amplitudes of IAWs. It was also found that a new wave is created with a high amplitude in the interacting region during collision depending on the plasma parameters.

Modeling of Hypothetical BeXAs2 (X = Si, Ge, Sn) Crystal Structure and Phonon Spectra

The paper presents ab initio density functional calculations of the geometry optimization of BeXAs2 (X = Si, Ge, Sn) crystal structure, primitive cells and phonon spectra in the centre of the Brillouin zone. Interpolation of phonon spectra was performed over the Brillouin zone using the Keating model. Ab initio frequency calculations are used to ascertain the Keating parameters via program optimization. The values of phenomenological parameters are in good agreement with the parameters of the chemical bond obtained by ab initio calculations. The partial phonon spectra are investigated. The structure of acoustic and optical branches of the full phonon spectrum is determined mostly by the ion mass ratio of the crystal compounds.

Impact of the electron to ion mass ratio on unstable systems in particle-in-cell simulations

The evolution of the Buneman and two-stream instabilities driven by a cold dilute mildly relativistic electron beam is studied as a function of the ion-to-electron mass ratio. The growth rates of both instabilities are comparable for the selected parameters if the realistic ion-to-electron mass ratio is used and the Buneman instability outgrows the two-stream instability for an artificially reduced mass ratio. Particle-in-cell simulations show that both instabilities grow independently during their linear growth phase. The much lower saturation amplitude of the Buneman instability implies that it saturates first even if the linear growth rates of both instabilities are equal. The electron phase space holes it drives coalesce. Their spatial size increases in time and they start interacting with the two-stream mode, which results in the growth of electrostatic waves over a broad range of wave numbers. A reduced ion-to-electron mass ratio results in increased ion heating and in an increased energy loss of the relativistic electron beam compared to that in a simulation with the correct mass ratio.