Multi-ion Plasma Research Articles

Dissipative electrostatic wave modulation in warm multi-ion dusty plasmas with superthermal electrons

Abstract A theoretical investigation has been carried out to explore the modulational instability (MI) of electrostatic waves in a warm multi-ion dusty plasma system containing positive ions, negative ions and positively or negatively charged dust in presence of superthermal electrons. With the help of the standard perturbation technique, it is found that the dynamics of the modulated wave is governed by a damped nonlinear Schrödinger equation (NLSE). Regions of MI of the electrostatic wave are precisely determined and the analytical solutions predict the formation of dissipative bright and dark solitons as well as dissipative first- and second-order rogue wave solutions. It is found that the striking features (viz., instability criteria, amplitude and width of rogue waves, etc.) are significantly modified by the effects of relevant plasma parameters such as degree of the electron superthermality, dust density, etc. The time dependent numerical simulations of the damped NLSE reveal that modulated electrostatic waves exhibit breather like structures. Moreover, phase plane analysis has been performed to study the dynamical behaviors of NLSE by using the theory of dynamical system. It is remarked that outcome of present study may provide physical insight into understanding the generation of several types of nonlinear structures in dusty plasma environments, where superthermal electrons, positive and negative ions are accountable (e.g. Saturn’s magnetosphere, auroral zone, etc.).

↵​Efficacy of Multi-ion Doped Plasma Spray Nano-hydroxyapatite Coated Titanium Implants in Long Bone Fracture Repair in Dogs- Radiographical and Bone Markers Evaluation

Background: Fracture of long bones is a common orthopaedic condition noticed in dogs and its primary goal is to completely restore the function of the injured limb as early as possible. Osteo-conductivity of hydroxyapatite can be improved further by decreasing the particle size to nanometre range and incorporation of inorganic materials in hydroxyapatite can enhance osteoblast cell material interactions. Strontium, Zinc, Silver and Fluorine are known to play an important role in the bone formation and also affect bone material characteristics such as crystallinity, degradation behaviour and mechanical properties. When doped with plasma spray nanohydroxyapatite, these multi-ions cause no harm to the physical environment during the degradation process of hydroxyapatite as these are nontoxic and play significant role in bone metabolism, growth and nourishment. Bone markers have tremendous potential as a rapid and sensitive method for assessing the response of the skeleton to medical or surgical interventions providing valuable information regarding bone turn over in animals. Hence, the current study was undertaken to evaluate the potential of multi-ion doped nano-hydroxyapatite coated intramedullary titanium implants in long bone fracture repair in dogs compared to the conventional intramedullary titanium implants through radiographical studies and evaluation of bone markers. Methods: Radiographical evaluation, Sandwich ELISA kits developed by Bioassay technology laboratory. Result: Plasma spray nano-hydroxyapatite coated titanium intramedullary implants have shown excellent osteo-conductivity when doped with multi-ions of Strontium, Zinc, Silver and Fluorine facilitating rapid osteoblastic activity and rapid bone turnover at the fracture site and complete fracture healing by 3rd week post-operatively as evidenced by radiographic scores and a peak BALP (Canine Bone Alkaline Phosphatase) values and early limb usage. Bone reabsorption and bone tissue remodelling due to osteoclastic action at the fracture site was quicker when the multi-ion doped nano-hydroxyapatite coated titanium intramedullary implants were used which is evidenced by the radiographic scores and highest CTX (Canine C-telopeptide of Type 1 Collagen) values indicating completion of fracture healing and near completion of bone tissue remodelling by 9th post-operative week in long bone fracture repair in dogs.

Thermal decoupling of deuterium and tritium during the inertial confinement fusion shock-convergence phase.

A series of thin glass-shell shock-driven DT gas-filled capsule implosions was conducted at the OMEGA laser facility. These experiments generate conditions relevant to the central plasma during the shock-convergence phase of ablatively driven inertial confinement fusion (ICF) implosions. The spectral temperatures inferred from the DTn and DDn spectra are most consistent with a two-ion-temperature plasma, where the initial apparent temperature ratio, T_{T}/T_{D}, is 1.5. This is an experimental confirmation of the long-standing conjecture that plasma shocks couple energy directly proportional to the species mass in multi-ion plasmas. The apparent temperature ratio trend with equilibration time matches expected thermal equilibration described by hydrodynamic theory. This indicates that deuterium and tritium ions have different energy distributions for the time period surrounding shock convergence in ignition-relevant ICF implosions.

Generalized impurity pinch in partially magnetized multi-ion plasma

In a two-ion-species plasma with disparate ion masses, heavy ions tend to concentrate in the low-temperature region of collisionally magnetized plasma and in the high-temperature region of collisionally unmagnetized plasma, respectively. Moreover, collisional magnetization can be determined as the ratio of the light ion gyrofrequency to the collision frequency of light and heavy ion species, and the behavior of this effect in the intermediate regime of partially magnetized plasma is predominantly dependent on this Hall parameter. Multi-ion cross-field transport has been described before in the collisionally magnetized plasma regime, and generalized pinch relations, which describe densities of ion species in equilibrium in that plasma, are found in the literature. In this paper, the role of collisional magnetization and Larmor magnetization in multi-ion collisional transport is clarified, and generalized pinch relations are extended to the partially magnetized regime in which the ion Hall parameter may be small, as long as electrons remain collisionally magnetized. Equilibrium ion density profiles have the same dependence on external forces and on each other regardless of collisional magnetization of ions. The expansion of the range of validity of multi-ion collisional transport models makes them applicable to a wider range of laboratory plasma conditions. In particular, ion density profiles evolve sufficiently fast for radial impurity transport to be observable around stagnation on MagLIF, leading to expulsion of heavy ion impurities from the hotspot as long as plasma becomes sufficiently collisionally magnetized during the implosion.

Influence of multi-ion on the dust grain surface potential of complex plasmas using non-Maxwellian approach

Dust grain surface potential in multi-ion plasmas having two negative ions within the context of kappa-distributed dusty plasma is studied analytically and numerically. The plasmas current equations Xe+-F--SF6- and Ar+-F--SF6- solved using the typical parameters of laboratory multi-ion plasmas and attained dust grain surface potential strongly depends on the plasma parameters for example kappa, density, and temperature ratios. The dust grain surface potential displays the non-monotonic behavior for values of the kappa, temperature ratio and for changed values of density ratios in the framework of both Xe+-F--SF6- and Ar+-F--SF6- plasmas. Additionally, the temperature ratio effect is minor on the dust grain surface potential. Our results show that considering the broad variety of Xe+-F--SF6- and Ar+-F--SF6- masses is of great importance and advantageous for the analyses of plasma physics, particularly the physics of multicomponent plasmas.

Eigenvalue solution for the ion-collisional effects on the fast and slow ion acoustic waves in multi-ion species plasmas

The fast and slow waves in multi-ion species collisionless plasmas have been widely studied, but the collision effect on ion acoustic waves is a difficult problem. In this paper, plasmas with azimuthal symmetry velocity distribution in different collisional regimes are studied by eigenvalue solution of the linearized Fokker–Planck equation. The frequency, damping rate and distribution function from the solutions are consistent with the analytical result in collisionless limit. For the fast wave, the damping rate agrees well with the prediction of both fluid theory in collision limit and kinetic theory in collisionless limit. But for the slow wave, the frequency and damping rate predicted by fluid theory are not accurate. In two-ion species plasmas, the light and heavy ion density perturbation phases of two-ion species are the same for the fast wave, but opposite for the slow wave. Polytropic index of C5H12 plasmas is also calculated, which is simply affected by mean-free paths of ions for the fast wave, but affected by multiple factors, such as mean-free paths, heat transfer and the opposite phases for the slow wave.

Nonlinear kinetic simulation study of the ion–ion streaming instability in single- and multi-ion species plasmas

The nonlinear evolution of the ion–ion streaming instability (IISI) is studied using numerical techniques novel to this problem that afford direct insight into the evolution of the particle distributions of each species. During the linear phase of the instability, we demonstrate quantitative agreement with linear kinetic theory. Subsequently, the electrostatic field generated by the IISI causes ring-like velocity distributions of ions to form that are both heated and slowed to varying degrees relative to their initial flows. Due to variation in the trapping conditions for ion species of differing charge-to-mass ratio, when flows of multiple species interact, the nonlinear evolution of each species can be starkly different: we show a case where a lighter ion species is completely stopped by a heavier ion species via the IISI alone (i.e., without collisions) and, for the first time, demonstrate how the IISI can introduce a relative flow between ion species that initially have the same flow velocities, thereby separating them.

Physics and applications of three-ion ICRF scenarios for fusion research

This paper summarizes the physical principles behind the novel three-ion scenarios using radio frequency waves in the ion cyclotron range of frequencies (ICRF). We discuss how to transform mode conversion electron heating into a new flexible ICRF technique for ion cyclotron heating and fast-ion generation in multi-ion species plasmas. The theoretical section provides practical recipes for selecting the plasma composition to realize three-ion ICRF scenarios, including two equivalent possibilities for the choice of resonant absorbers that have been identified. The theoretical findings have been convincingly confirmed by the proof-of-principle experiments in mixed H–D plasmas on the Alcator C-Mod and JET tokamaks, using thermal 3He and fast D ions from neutral beam injection as resonant absorbers. Since 2018, significant progress has been made on the ASDEX Upgrade and JET tokamaks in H–4He and H–D plasmas, guided by the ITER needs. Furthermore, the scenario was also successfully applied in JET D–3He plasmas as a technique to generate fusion-born alpha particles and study effects of fast ions on plasma confinement under ITER-relevant plasma heating conditions. Tuned for the central deposition of ICRF power in a small region in the plasma core of large devices such as JET, three-ion ICRF scenarios are efficient in generating large populations of passing fast ions and modifying the q-profile. Recent experimental and modeling developments have expanded the use of three-ion scenarios from dedicated ICRF studies to a flexible tool with a broad range of different applications in fusion research.

Quadruple Beltrami state in electron-depleted multi-ion dusty plasmas

In magnetized electron-depleted multi-ion dusty plasmas, a possibility of self-organization is determined. Making use of the equation of motion of the plasma's mobile species, i.e., a positive ion and two types of negative ions with Ampère's law, we obtain a quadruple Beltrami field. This higher order Beltrami field is characterized by four scale parameters. We have investigated the generation of self-organized structures. The typical length of these structures is attributed to the skin depth λp of positive ions. The influence of Beltrami parameters and scale parameters on the structure formation has also been investigated. It is found that there is a possibility of the formation of large scale structures of the order of system size and the formation of small scale structures of the order of skin depth simultaneously in the electron depleted multi-ion dusty plasmas, which are very useful to explain the dynamo theory. This study should be useful to describe the relaxed structures in space plasmas such as the D-region of Earth's mesosphere and F-ring of Saturn and in laboratory work where the dust particles are present as impurities.

New method for solving strong conservative odd parity nonlinear oscillators: Applications to plasma physics and rigid rotator

In the present work, a new method for solving a strong nonlinear oscillator equation of the form ẍ + F(x) = 0, where F(−x) = −F(x), is carried out. This method consists of approximating function F(x) by means of a suitable Chebyshev polynomial: F(x) ≈ P(x) = px + qx3 + rx5, and then, the original oscillator is replaced by the cubic–quintic Duffing equation ẍ + px + qx3 + rx5 = 0 with arbitrary initial conditions, which admits the exact solution in terms of elliptic functions. The efficacy of the present method is demonstrated through the fluid multi-ion plasma equations and a generalized pendulum problem. For the generalized pendulum problem, the governing motion is directly reduced to the cubic–quintic Duffing oscillator with the help of the Chebyshev polynomial, and the approximate analytical and exact solutions are obtained. In addition, the comparison between our solutions and the Runge–Kutta numerical solution is examined. Moreover, the periodic time formula of the oscillations for both the approximate analytical solution and the exact solution is deduced, and the comparison between them is implemented. With respect to the plasma application, the fluid plasma equations of its particles are reduced to the Extended Korteweg–de Vries (EKdV) equation utilizing a reductive perturbation method. Then, we proved for the first time that any undamped polynomial oscillator of the nth degree can be reduced to a (2n − 1)th odd parity Duffing. Accordingly and after applying the previous theory to the EKdV equation, it was converted to the cubic–quintic Duffing equation. Finally, we can deduce that our new solutions and theory help us to understand and investigate many nonlinear phenomena in various branches of science.

Stability of ion-acoustic solitons in a multi-ion degenerate plasma with the effects of trapping and polarization under the influence of quantizing magnetic field

ABSTRACT Multi-dimensional instability of ion acoustic solitary waves (IASWs) in a magnetized, collisionless, degenerate multi-ion plasma system with trapping distributed electrons in the presence of a quantizing magnetic field has been theoretically investigated. The dispersion properties of the linear IASWs are discussed. The dynamics of the nonlinear Zakharo-Kuznetsov (ZK) equation is also analyzed for investigation of the solitary waves. The effects of the trapped electrons, the electron temperature and the mass-to-charge for positive to negative ions on the phase velocity are discussed. Only compressive solitary waves are produced, those are affected by the system parameters like the number density ratio of negative to positive ions and the polarization effect. The waves growth rate is calculated. The effects of the previous plasma parameters on the instability growth rate are also discussed. The present investigation could be helpful in understanding the propagation and the instability of the detected IASWs waves in magnetized multi-ion plasmas which are observed in dense quantum plasmas such as those existing in white dwarfs and in the intense-laser plasma interactions where the trapping and the polarization effects are important.

Heat pump via charge incompressibility in a collisional magnetized multi-ion plasma.

Stratification due to ion-ion friction in a magnetized multiple-ion species plasma is shown to be accompanied by a heat pump effect, transferring heat from one ion species to another as well as from one region of space to another. The heat pump is produced via identified heating mechanisms associated with charge incompressibility and the Ettingshausen effect. Besides their academic interest, these effects may have useful applications to plasma technologies that involve rotation or compression.

Dynamics of ion-acoustic waves in nonrelativistic magnetized multi-ion quantum plasma: the role of trapped electrons

The presented work provides a new perspective of quantum nonlinear propagation of ion-acoustic (IA) waves in a magnetized collisionless and dissipative multi-ion plasma system, composed of cold positive and negative charged nonrelativistic ions, negatively charged immobile heavy ions and trapped electrons; all existed in a quantizing magnetic field. We address the reductive perturbation method to derive the Korteweg-de Vries- Burgers (KdV-Burgers) and modified KdV-Burgers equations. The bifurcation theory of planar dynamical systems is applied to investigate the existence of the solitary wave and the periodic traveling wave solutions of the resulting mKdV-Burgers equation. Accordingly, the phase portrait topology is illustrated for this equation. To study the nonlinear waves in case of mKdV- Burgers, we obtain some interesting physical solutions for mKdV- Burgers. These solutions are in the form of soliton, a combination between the shock and the soliton, and finally monotonic and oscillatory shock waves. Only rarefactive IA waves are obtained for the slow mode of phase velocity. It is found that the IA solitons, IA shocks are affected by the plasma system parameters. The presented theoretical research can be successfully implemented to understanding the solitary and shocks structures in dense magnetized quantum plasmas such as those existing in white dwarfs and in the intense-laser plasma interactions.

Simulation study on nonlinear structures in nonlinear dispersive media.

In this work, the dynamic mechanism scenario of nonlinear electrostatic structures (unmodulated and modulated waves) that can propagate in multi-ion plasmas with the mixture of sulfur hexafluoride and argon gas is reported. For this purpose, the fluid equations of the multi-ion plasma species are reduced to the evolution (nonplanar Gardner) equation using the reductive perturbation technique. Until now, it has been known that the solution of nonplanar Gardner equation is not possible and for stimulating our data, it will solve numerically. At that point, the present study is divided into two parts: the first one is analyzing planar and nonplanar Gardner equations using the Adomian decomposition method (ADM) for investigating the unmodulated structures such as solitary waves. Moreover, a comparison between the analytical and numerical simulation solutions for the planar Gardner equation is examined, showing how powerful the ADM is in finding solutions in the short domain as well as its fast convergence, i.e., the approximate solution is consistent with the analytical solution for the planar Gardner equation after a few iterations. Second, the modulated envelope structures such as freak waves (FWs) are investigated in the framework of the Gardner equation by transforming this equation to the nonlinear Schrödinger equation (NLSE). Again, the ADM is used to solve the NLSE for studying FWs numerically. Furthermore, the effect of physical parameters of the plasma environment (e.g., Ar+-SF5 +-F--SF5 - plasma) on the characteristics of the nonlinear pulse profile is elaborated. These results help in a better understanding of the fundamental mechanisms of fluid physics governing the plasma processes.

Quadruple Beltrami state in electron-depleted multi-ion dusty plasmas

Quadruple Beltrami state in electron-depleted multi-ion dusty plasmas

Electrostatic solitary structures in warm multi-ion dusty plasmas: The effect of an external magnetic field and nonthermal electrons

Adopting a multi-fluid dynamical approach, the propagation of weakly nonlinear electrostatic solitary waves in a warm multi-ion dust plasma is investigated. In particular, a plasma is composed of positively and negatively charged ions and positively or negatively charged dust in the presence of superthermal electrons immersed in an external magnetic field. In the linear regime, two modes exist, namely, the slow and fast ion-acoustic modes. Employing the reductive perturbation technique, the governing equation of the nonlinear propagation for the electrostatic solitary pulse is derived. The polarity and structural characteristics (amplitude and width) of the localized electrostatic pulse in the plasma are thus analyzed for various values of relevant plasma configurations, namely, the degree of the superthermality (κ), the magnetic field strength Ωj, and the adiabatic ion thermal pressure coefficient σj. Our investigations should be useful to better understand the characteristics of the low-frequency electrostatic solitary wave that are ubiquitous in the laboratory and space plasmas, where a warm dusty multi-ion plasma with the energetic (suprathermal) electrons exists and an external magnetic field is included.

Heavy Ion Acceleration by Super-Alfvénic Waves

Abstract A generation mechanism of super-Alfvénic (SPA) waves in multi-ion species plasma is proposed, and the associated heavy ion acceleration process is discussed. The SPA waves are thought to play important roles in particle acceleration since they have large wave electric fields because of their high phase velocity. It is demonstrated by using full particle-in-cell simulations that large amplitude proton cyclotron waves, excited due to proton temperature anisotropy, nonlinearly destabilize SPA waves through parametric decay instability in a three-component plasma composed of electrons, protons, and α particles. At the same time, α cyclotron waves get excited via another decay instability. A pre-accelerated α particle resonates simultaneously with the two daughter waves, the SPA waves and the α cyclotron waves, and it is further accelerated perpendicular to the ambient magnetic field. The process may work in astrophysical environments where a sufficiently large temperature anisotropy of lower mass ions occurs.

Quantum statistical approach for ionization potential depression in multi-component dense plasmas

Theoretical modeling of ionization potential depression (IPD) and the related ionization equilibrium in dense plasmas, in particular, in warm/hot dense matter, represents a significant challenge due to ionic coupling and electronic degeneracy effects. Based on the dynamical structure factor (SF), a quantum statistical model for IPD in multi-ionic plasmas is developed, where quantum exchange and dynamical correlation effects in plasma environments are consistently and systematically taken into account in terms of the concept of self-energy. Calculations for IPD values of different chemical elements are performed with the electronic and ionic SFs. The ionic SFs are determined by solving the Ornstein–Zernike equation in combination with the hypernetted-chain closure relation. As a further application of our approach, we present results for the charge state distribution of aluminum plasmas at several temperatures and densities through solving the coupled Saha equations.

Dust Ion Acoustic Solitary Waves in Multi-Ion Dusty Plasma System

A theoretical work has done to observe the existence of dust ion-acoustic (DIA) solitary waves (SWs) in a multi-ion dusty plasma system consisting of inertial positive and negative ions, Maxwell’s electrons, and arbitrary charged stationary dust. In this short communication, our research declares that with these components the derivation of Korteweg-de Vries (K-dV) and mixed K-dV (mK-dV) is possible. Here reductive perturbation method has been employed in all these approaches. The first K-dV equation has been derived which gave both bright and dark solitons but for a very limited region. Then the mK-dV equation has been derived that gave bright soliton for a large region, but no dark soliton has been observed.

Terahertz radiation from multi ion plasma irradiated by two cross focused Gaussian laser beams

Terahertz (THz) radiation generation by nonlinear coupling of two color Gaussian laser beams in a plasma with multi-ion species is numerically investigated by taking into account the nonlinearity due to ponderomotive force and space-charge field. By calculating the modification of electron density distribution of such plasma, coupled differential equations governing the evolution of two laser beams' spot size and the outcome THz wave amplitude are established. The influence of the ionic species density and charge composition on the cross focusing of laser beams as well as generation of THz radiation is studied. The results mainly demonstrated that nonlinear effects in a multiply ionized plasma are excited stronger in comparison to the singly ionized one. It was found that the presence of ion species of higher charge enhances the cross focusing of beams and, consequently, THz field amplitude. The generated THz emission also strongly depends on the density of ionic species. The results showed that the minimum output of THz radiation is related to the higher density of singly charged ionic species. Moreover, it was found that the maximum value of THz amplitude takes place within a specific range of laser intensities.