Inhomogeneous Dusty Plasma Research Articles

Dust magnetoacoustic waves in an inhomogeneous cylindrical four-component dusty plasma in the presence of polarization force

Abstract Dust magnetoacoustic waves have been examined in an inhomogeneous, bounded, cylindrical dusty plasma containing oppositely polarized dust particles. Considering polarization force, dust dynamics in r − θ plane is studied in the presence of inhomogeneous external magnetic field along z axis. At equilibrium, the dusty plasma components are supposed to follow Gaussian density distribution. Using reductive perturbation method (RPM), a variable coefficient cylindrical Kadomtsev–Petviashvili (VCCKP) equation has been derived. For weak azimuthal perturbation, an analytical solution, obtained by Zhang (“Exact solutions of a kdv equation with variable coefficients via exp-function method,” Nonlinear Dynam., vol. 52, nos. 1–2, pp. 11–17, 2008) using Exp-function method, is chosen. Phase velocity of dust magnetoacoustic wave is found to be modified by the density inhomogeneities, polarization force, dust charge state ratio and ion-to-electron temperature ratio. Spatio-temporal evolution of the dust number densities has been noticed. Existence of the compressive electromagnetic solitary waves is observed numerically for the chosen dusty plasma parameter range. The impacts of the inhomogeneity, polarization force, dust charge state ratio and ion-to-electron temperature ratio on the relative amplitude of the dust magnetoacoustic wave are also discussed.

Novel nonlinear quantum dust acoustic waves for modified variable coefficients Zakharove–Kusnetsov equation in dusty plasma

In this paper, the direct similarity reduction method is used to reduce the modified variable coefficient Zakharove–Kusnetsov equation (vcmZK), which represents the propagation of quantum dust acoustic waves (QDAWs) in an inhomogeneous magnetized dusty plasma field, into a nonlinear ordinary differential equation (NODE). Moreover, the Jacobi elliptic method is used to solve the NODE, where many novel double periodic, kink, and solitary wave solutions are obtained. Additionally, we have chosen to plot periodic, kink, and soliton QDAWs solutions according to some choices for the variable coefficients. According to the a chieved results, we can conclude that the choices of the functional forms of the variable coefficients can control the QDAWs propagation. Finally, the new discovered results may have many important applications in astrophysics, atmospheric science, nanotechnology, and industrial plasma physics.

SO-FDTD simulation on the transmission characteristics of terahertz waves in inhomogeneous magnetized dusty plasma

SO-FDTD simulation on the transmission characteristics of terahertz waves in inhomogeneous magnetized dusty plasma

Overtaking interactions in a strongly coupled inhomogeneous dusty plasma: the role of polarization force

The nonlinear propagation of dust-acoustic waves (DAWs) is considered in a collisionless, inhomogeneous, weakly and strongly coupled dusty plasma composed of negatively charged dust, electrons, and ions. The reductive perturbation method is used to derive a Korteweg–de Vries equation (KdV). It is found that the KdV solitons are affected by the plasma parameters, whereas only rarefactive DAWs are obtained. Hirota’s bilinear approach is used to investigate the overtaking collision of two and three-soliton solutions. Physical parameters such as polarization, and the ions and electrons density gradient scale lengths have a significant impact and cause alterations in the behaviour of the solitons. Notably, as the polarization and ion density gradient scale length increase, the amplitude and width of the solitons decrease. Furthermore, the system parameters also affect the phase shifts of the solitons. The findings presented here have potential applications in the study of acoustic waves in compact astrophysical systems, where quantum polarization and inhomogeneity effects cannot be ignored, as well as in laboratory plasmas.

Propagation of nonlinear dust-acoustic solitary waves under the effect of non-extensive electrons in inhomogeneous collisional magnetized dusty plasma

Propagation of nonlinear dust-acoustic solitary waves under the effect of non-extensive electrons in inhomogeneous collisional magnetized dusty plasma

Numerical study of instabilities in magnetized inhomogeneous collisional dusty plasmas under dust dynamics

Numerical study of instabilities in magnetized inhomogeneous collisional dusty plasmas under dust dynamics

Instabilities in magnetized inhomogeneous dusty plasmas with the effect of recombination

An analytical formalism to understand the impact of various parameters on evolving instabilities in inhomogeneous collisional dusty plasmas is presented here under the effect of recombination. The basic fluid dynamics for electrons and singly charged cold ions is carried out including recombination and collision at constant rate at the surface of dust particles. Dust particles are considered to be static with unperturbed density. Normal mode analysis method has been used along with linear approximation to get perturbed densities (n i1, n e1) which are used along with quasi-neutrality condition to get perturbed potential using Poisson’s equation to obtain dispersion relation. While other authors have detected instabilities in unmagnetized plasmas, here this method has been successfully realized in presence of static magnetic field at various propagation angle and allowed the straightforward calculation of growth rates of observed instability. An extensive study of the unstable modes has been done which are well discriminated and plotted with respect to different plasma parameters like dust charge, dust density, propagation angle, magnetic field, electrostatic potential along with plasma oscillation wavelength to Debye wavelength ratio. We have observed in the said model that the presence of dust particles and propagation angle of applied magnetic field are affecting significantly the growth rate of instability as compared to magnetic field and recombination.

A Comparative Study of the Transmission Properties of Electromagnetic Waves in Inhomogeneous Dusty Plasma

A Comparative Study of the Transmission Properties of Electromagnetic Waves in Inhomogeneous Dusty Plasma

Shock waves in a strongly coupled inhomogeneous dusty plasma

Nonlinear theory for certain dust acoustic waves has been developed for a strongly coupled inhomogeneous collisionless dusty plasma containing dust particles of different sizes. The generalized hydrodynamic set of partial differential equations is considered to describe the fluid model of the present nonlinear system. A reductive perturbation technique is employed on this nonlinear set of equations to derive a variable coefficient Korteweg-deVries (KdV)–Burgers equation with a forcing term. The generalized expansion method is performed to obtain an analytic expression for the solution. This analytic solution describes the monotonic kink-type shock waves, due to the dominant nature of the dissipation term over the dispersion term. In addition to the effects of inhomogeneity and grain size distribution, the effects of nonthermal ions, dust–dust correlation and ion temperature on the wave propagation are investigated. Also, a steady-state monotonic shock solution of the KdV-Burgers equation is obtained numerically. The obtained results are discussed in the context of some dusty plasmas, previously reported experimentally or theoretically.

The shock wave solutions of modified ZK Burgers equation in inhomogeneous dusty plasmas

Abstract This paper offers a shock wave solution to modified Zakharov–Kuznetsov (MZK) Burgers equation in inhomogeneous dusty plasmas with external magnetic field. For this purpose, the fluid equations are reduced to an MZK Burgers equation containing variable coefficients by reductive perturbation method. With the aid of travelling-wave transformation technique, we obtain the analytical oscillatory shock wave solution and monotonic shock wave solution for MZK Burgers equation. The effects of inhomogeneity, external magnetic field, dust charge variation on characteristics of two types of shock waves are examined in detail.

Effect of levitated dust kinetics in the dynamic evolution of inhomogeneous plasma sheath

The main goal here is to study theoretically the formation of plasma sheath in an inhomogeneous dusty plasma. The effect of weak ionization of the dust grains as similar to the Townsend discharge has been incorporated to see how it influences the evolution of sheath. Sheath equation has been derived to describe the properties of sheath structures analytically and numerically. It has shown that the ionization along with the inhomogeneity affects significantly the growth of sheath which has been highlighted elaborately for some typical plasma parameters. After getting well defined sheath region, dynamical behaviour of levitated dust grains into the sheath has been studied. The totality of the findings has been centred around the estimation of dust surface potential, dust sizes along with the generation of net force on dust grains. Both inhomogeneous and ionization effects allow the dust grains in acquiring different potential to sustain equilibrium in different places. As a result of this, nebulons and the dust cloudlike structures are electrically charged.

Studies on the propagation properties of THz wave in inhomogeneous dusty plasma sheath considering scattering process

The plasma sheath formed during the reentry process is able to block the detection and communication to the hypersonic vehicle. Various of interactions occur during the propagation of EM wave in the plasma sheath. In addition, the dusty particles formed during the ablation of the protective layer make this process more complicated. Dusty plasma sheath is an important factor that affect the detection of hypersonic vehicle. In this work, the propagation properties of THz wave in inhomogeneous dusty plasma sheath are studied. The flow field distribution around the hypersonic vehicle is simulated first. Then the electron density is calculated using equilibrium constant method of the 7-species reacting air model. And the collision frequency is calculated based on the results of the flow field simulation. The absorption and scattering process are studied using scattering matrix method and Mie scatter theory, respectively. The propagation properties are calculated considering the influences of the flight speed, the flight altitude, the radius, the number density and the kind of the ablation particles. The calculation results show that with the increase of THz wave frequency, the transmittance increases firstly and then oscillates. The shape of the transmittance curve is determined by the flight speed, the flight altitude, the radius, the number density and the kind of the ablation particles. The main loss mechanisms in different wave bands has also been discussed and the optimum transition band is given. This work shows that THz wave has good potential applications in hypersonic vehicle detection. It also provides a method to select the optimum detection frequency band.

Research on Electromagnetic Wave Propagation Characteristics of Fully Ionized Inhomogeneous Dusty Plasma in a Magnetized BGK Model

Starting from Boltzmann's approximate equation, the Bhatnagar-Gross-Krook (BGK) collision model of inhomogeneous dusty plasma is derived. In the case of an external magnetic field, the expression of the dielectric coefficient of the dusty plasma under the collision condition of the fully ionized BGK is obtained by combining the collision effect and charging effect of the dusty plasma. By using the transfer matrix method, the reflection coefficient and transmission coefficient of electromagnetic (EM) waves under different external magnetic fields and dusty plasma parameters are calculated, and the propagation characteristics of dusty plasma under the nonuniform fully ionized BGK collision model are analyzed. Results show that the inelastic collision absorption effect between electrons and dust particles is the strongest when the incident frequency of EM waves is close to or equal to the charging frequency of dusty plasma. Meanwhile, the size and density of dust particles can affect the effective collision frequency of dusty plasma and strongly influence the EM wave propagation characteristics. By analyzing the propagation characteristics of different external magnetic fields to circularly polarized waves, changing the size and direction of the external magnetic field can artificially control the low coefficient band range and size of the EM wave transmission coefficient in dusty plasma. These results provide a theoretical basis for the study of EM wave propagation in weakly impacted fully ionized dusty plasma and communication problems in near space.

Nonlinear dust acoustic waves in an inhomogeneous magnetized quantum dusty plasma

Propagations of nonlinear quantum dust acoustic waves (QDAWs) in an inhomogeneous magnetized dusty plasma model which is three-dimensional collisionless, and having number density gradients of its components along x-direction is investigated. This model consisting of ions, electrons and charged dust particles in the presence of an external static magnetic field. The reductive perturbation method was adopted to derive the modified Zakhavov Kusnetsov equation (MZK) whose coefficients are space dependent. The incorporation of inhomogeneity caused by nonuniform equilibrium values of particle density leads to a significant modification to the nature of nonlinear QDAWs. Solutions for the MZK equation are obtained by using a generalized expansion method. The solutions have two parts; amplitude factor and the superposition of bell-shaped solitary wave. The soliton amplitude, width, and velocity depends on the plasma inhomogeneities. Findings in these numerical investigations should be useful in understanding the astrophysical plasmas and ultra small micro- and nano-electronic devices.

Study of the Propagation Characteristics of Terahertz Waves in a Collisional and Inhomogeneous Dusty Plasma with a Ceramic Substrate and Oblique Angle of Incidence

In this paper, the propagation properties of a terahertz (THz) wave in a collisional and inhomogeneous dusty plasma with a ceramic substrate and oblique angle of incidence are studied using the scattering matrix method. The influence of the various corresponding parameters, such as the frequency of the THz wave, angle of incidence, electron density, radius and density of the dust particles, and the collision frequency, on the absorbance and transmittance is calculated. The results of the simulation indicate that an increase in the wave frequency increases the transmittance and decreases the absorbance. Moreover, the absorbance of a THz wave in a dusty plasma with a ceramic substrate increases with an increase in the incident angle, maximum electron density, coefficient of steepness, density and radius of the dust particles, and collision frequency. These results provide an important theoretical basis for the problem of communication blackout between ground and spacecraft.

Study on the Propagation Characteristics of Terahertz Waves in Dusty Plasma with a Ceramic Substrate by the Scattering Matrix Method.

The propagation characteristics of terahertz (THz) waves incident vertically into inhomogeneous and collisional dusty plasma with a ceramic substrate are studied using the scattering matrix method (SMM). The effects of the incident wave frequency and plasma parameters, such as the maximal electron density, dust particle density, dust particle radius and collision frequency, on the reflectance and transmittance of THz waves in the dusty plasma are discussed. In addition, the differences of the propagation properties in the dusty plasma, with and without ceramic substrate, are analyzed. Meanwhile, the differences of the propagation properties in dusty plasma and common plasma, respectively, with ceramic substrate are also compared. Simulation results show that the substrate and dust particles have significant influence on the propagation characteristics of THz wave in plasma sheath. Finally, the transmission increases with the increase of electron density, dust density, dust particle radius and collision frequency.

Research on the propagation properties of THz circularly polarized wave in BGK model inhomogeneous dusty plasma

When a hypersonic vehicle flies near space, a layer of complex dusty plasma will form around the vehicle under the influence of high temperature, which will cause radar signal attenuation (ATT) to different degrees and lead to communication barriers. Therefore, studying the interaction mechanism between electromagnetic waves and dusty plasma is important. In this paper, the Bhatnagar–Gross–Krook collision model of non-uniform dusty plasma is derived on the basis of Boltzmann's approximate equation. In addition, the modified expression of a dielectric coefficient of weakly ionized dusty plasma is obtained under the condition of magnetization. With the Wentzel–Kramers–Brillouin method, the ATT coefficients of terahertz wave with different external magnetic fields and dusty plasma parameters are calculated. Results show that a strong external magnetic field will cause the ATT of the right-hand circular polarized wave to produce a low absorption band, whereas the ATT of the left-hand circular polarized wave will evidently weaken. The electron concentration, dust concentration, dust particle radius, collision frequency, and charging frequency also influence the ATT under the external magnetic field. These studies provide theoretical references for the research on the blackouts of hypersonic vehicles.

Excitation of dust acoustic shock waves in an inhomogeneous dusty plasma

An experimental investigation of the propagation characteristics of shock waves in an inhomogeneous dusty plasma is carried out in the dusty plasma experimental device. A homogeneous dusty plasma, made up of poly-dispersive kaolin particles, is initially formed in a direct current glow discharge argon plasma by maintaining a dynamic equilibrium of the pumping speed and the gas feeding rate. Later, an equilibrium density inhomogeneity in the dust fluid is created by introducing an imbalance in the original dynamic equilibrium. Non-linear wave structures are then excited in this inhomogeneous dusty plasma by a sudden compression in the dust fluid. These structures are identified as shock waves, and their amplitude and width profiles are measured spatially. The amplitude of a shock structure is seen to increase, whereas the width broadens as it propagates down a decreasing dust density profile. A modified-Korteweg–de Vries–Burger equation is derived and used to provide a theoretical explanation of the results, including the power law scaling of the changes in the amplitude and width as a function of the background density.

Inhomogeneity of Structural and Dynamical Characteristics of Dusty Plasma in a Gas Discharge

Dusty plasma crystals are commonly considered as spatially homogeneous structures with equal values of their structural and thermodynamic parameters in various regions of the system. Inhomogeneity of the interparticle distance, the amplitude of thermal particle oscillations, the Lindemann parameter, and the coupling parameter is shown to arise even in a system of particles with a simplified interaction model including a screened Coulomb potential and a parabolic trap. The kinetic energy distribution for particles in an inhomogeneous dusty plasma monolayer is investigated: it is shown that the mean kinetic energy of particles in the central part of the structure can differ significantly from the mean kinetic energy of particles on its periphery due to the inhomogeneity of structural parameters. The detected effects are verified using analytical methods and numerical simulations and by comparison with a dusty plasma experiment in a dc glow discharge. The results obtained are of great importance for investigating finite systems of like charges in a trap and studying the mechanism of phase transitions in dusty plasma systems.

The Applicability of WKB Method in Studying Inhomogeneous Dusty Plasma

In this article, the applicability of the Wentzel–Kramer–Brillouin (WKB) method in studying inhomogeneous dusty plasma is discussed. First the power transmission coefficient of electromagnetic waves in inhomogeneous dusty plasma is derived based on the WKB method. Then, the power transmission coefficients of the double exponential and hyperbolic electron number density distribution models are numerically simulated. The numerical results reveal that the power transmission coefficient increases with the increase of incident wave frequency. Furthermore, comparing the power transmission coefficient of the WKB method and the analytical method in common plasma and dusty plasma, it is found that the WKB method is more applicable for common plasma. Finally, the applicable region of the WKB method for dusty plasma is discussed. The results reveal that the electron number density distribution is crucial for the applicable region of the WKB method, as well as for the incident wave frequency.