Inhomogeneous Dusty Plasma Research Articles

Dust drift shock waves with non-Maxwellian ion population in nonuniform collisional dusty plasmas in planetary environments

Linear and nonlinear propagation of dust drift waves are investigated in the presence of Cairns and Kappa distributed ion population and Boltzmannian electrons. It is found the frequency of the dust drift wave is greatest for the Cairns, intermediate for Kappa and the least for the Maxwellian distributed ions. Using the drift approximation, a nonlinear equation is derived for the dust drift shock waves which reduces to a Korteweg-de Vries-Burgers (KdVB)-like equation in the comoving frame of reference. The solution of the KdVB-like equation is obtained using the tanh method. It is found that the non-Maxwellian ion population, dust neutral collision frequency as well as the inverse dust density scale length inhomogeneity alter the propagation characteristics of the nonlinear dust drift shock waves. Interestingly, it is found that the non-Maxwellian ion population modifies the scale lengths over which the nonlinear structures are formed. The work presented here may be useful to understand the low frequency electrostatic shock waves in inhomogeneous dusty plasmas such as those found in planetary environments.

The Effects of Inhomogeneity and Adiabatic Dusty Charge Fluctuation on Solitary Waves

Using the perturbation method, the modified variable coefficient Kadomtsev-Petviashvili (MKP) equation governing nonlinear dust acoustic solitary waves is for the first time derived with the combined effects of adiabatic dust charge fluctuation and higher-order transverse perturbation in inhomogeneous dusty plasmas due to the spatial gradients of dust charge and plasma densities. The MKP equation is reduced to the standard Kadomtsev-Petviashvili (KP) equation. The numerical results show that inhomogeneity has strong influence on the nonlinear properties of dust acoustic solitary waves.

Roles of polarization force and nonthermal electron on dust-acoustic waves in an inhomogeneous dusty plasma with positively charged dust

The influence of polarization force (PF) (arises due to dust density inhomogeneity), nonthermal electrons, and dust density inhomogeneity associated with positively charged dust on linear dust-acoustic (DA) waves in an inhomogeneous unmagnetized dusty plasma are investigated. By taking the normal mode analysis, the dispersion relation in such a non-Maxwellian inhomogeneous plasma is obtained, and that the dispersion properties of the DA waves are significantly modified by the presence of PF and nonthermal electrons. The PF is increased with the increase of nonthermal electrons. It is found that the phase speed of the DA waves is significantly decreased with the presence of PF and nonthermal electrons. The potential associated with the DA waves is de-enhanced with the increase of equilibrium dust number density. The role of positive dust number density on dispersion properties is also shown. The present findings relevant to different scenarios in laboratory and space dusty plasma, such as Martian ionosphere, solar flares, TEXTOR-94 tokamak plasmas, rf excited argon magnetoplasma, etc., can be useful to understand the properties of localized electrostatic disturbances in those dusty plasma system, are also briefly addressed.

Drift instability grow rates in non-ideal inhomogeneous bi-dust plasmas

Dust Acoustic Wave propagation in unmagnetized inhomogeneous dusty plasmas has been extensively studied, considering non-ideal Padé type state equation. In this paper, the drift instability is analyzed in a weakly magnetized dusty plasma including inhomogeneities of the type called gradient instabilities considering two kind of dust particles. A fully kinetic approach is achieved using a dispersion relation in a polynomial form through a multipole approximation. The drift instability for the dust acoustic mode is extensively analyzed including the non-ideal effect in dusty plasmas, using the state equation introduced by Ree and Hoover. These unstable modes are well discriminated and treated as a function of the density gradient and dust grain radius. Temperature gradients and charging processes will be ignored.

Instability of a magnetic drift wave in the vicinity of the dust-ion hybrid resonance

Low-frequency electromagnetic waves propagating perpendicular to the gradients of the density and magnetic field in an inhomogeneous dusty plasma whose mass density is determined primarily by the dust component are analyzed. It is shown that, in analyzing the dispersion properties of inhomogeneous plasma, it is important to take into account the dynamic properties of ions in the vicinity of the dust-ion hybrid resonance. The conditions for the onset of instability of a magnetic drift wave are investigated for different relations between parameters of the inhomogeneity and the value of the Alfven velocity. The differences from the previous results, as well as possible astrophysical applications, are discussed.

Coupled dispersive drift acoustic modes in inhomogeneous dusty plasmas with different nonthermal distributions for electrons and ions

Linear dispersion characteristics of the coupled drift acoustic modes are investigated in inhomogeneous dusty magnetoplasmas both when the dust is considered immobile and when the dust dynamics is taken into account in the presence of nonthermal population of electrons and ions. In this regard, Cairns and Kappa distributed electrons and ions are considered. It is found that the nonthermal distributions affect the phase velocities and the fundamental scalelengths of the plasma. It is found that for both the ion and dust dynamics driven waves, the phase velocities are highest for Cairns, intermediate for Kappa, whereas they are minimum for the Maxwellian distributed electrons. The work presented here may be useful to understand the low frequency electrostatic modes in inhomogeneous dusty plasmas such as those found in planetary environments.

Dust-acoustic solitary waves in a strongly coupled inhomogeneous dusty plasma in the presence of polarization force and effective dust-temperature

The nonlinear propagation of the dust-acoustic waves is studied in a strongly coupled inhomogeneous dusty plasma which consists of the strongly correlated negatively charged dust grains and weakly correlated electrons and ions. The Korteweg-de Vries equation with variable coefficients and an additional term due to the density gradient is deduced, and its solution is found by appropriate transformations. The propagation of two possible modes (fast and slow) and their evolution are investigated. Only the fast rarefactive solitary waves are found to propagate in such plasma with parameter ranges corresponding to the experimental conditions. It is shown that the special patterns of nonlinear DA waves (e.g., amplitude and width) are significantly modified in a way that depends upon the effects of polarization force (which arises due to the interaction between thermal ions and highly negatively charged dust grains), effective dust-temperature (which arises from the electrostatic interactions among highly negatively charged dust and from the dust thermal pressure), equilibrium electron density, and ion temperature. The amplitude of solitary waves also decreases as the wave propagates in the direction of increasing dust concentration.

The parametric decay of dust ion acoustic waves in non-uniform quantum dusty magnetoplasmas

The parametric decay instability of a dust ion acoustic wave into low-frequency electrostatic dust-lower-hybrid and electromagnetic shear Alfvén waves has been investigated in detail in an inhomogeneous cold quantum dusty plasma in the presence of external/ambient uniform magnetic field. The quantum magnetohydrodynamic model of plasmas with quantum effect arising through the Bohm potential and Fermi degenerate pressure has been employed in order to find the linear and nonlinear responses of the plasma particles for three-wave nonlinear coupling in a dusty magnetoplasma. A relatively high frequency electrostatic dust ion acoustic wave has been taken as the pump wave. It couples with two other low-frequency internal possible modes of the dusty magnetoplasma, viz., the dust-lower-hybrid and shear Alfvén waves. The nonlinear dispersion relation of the dust-lower-hybrid wave has been solved to obtain the growth rate of the parametric decay instability. The growth rate is at a maximum for a small value of the external magnetic field B0. It is noted that the growth rate is proportional to the unperturbed electron number density noe and is independent of inhomogeneity beyond Le=2 cm. An extraordinary growth rate is observed with the quantum effect.

Effects of adiabaticity and non-adiabaticity of dust charge fluctuation on the propagation of the dust ion acoustic waves in inhomogeneous dusty plasma

A theoretical investigation has been made for adiabatic positive and negative dust charge fluctuations on the propagation of dust-ion acoustic waves (DIAWs) in a weakly inhomogeneous, collisionless, unmagnetized dusty plasmas consisting of cold positive ions, stationary positively and negatively charged dust particles and isothermal electrons. The reductive perturbation method is employed to reduce the basic set of fluid equations to the variable coefficients Korteweg–de Vries (KdV) equation. Either compressive or rarefactive solitons are shown to exist depending on the critical value of the ion density, which in turn, depends on the inhomogeneous distribution of the ion. The dissipative effects of non-adiabatic dust charge variation has been studied which cause generation of dust ion acoustic shock waves governed by KdV-Burger (KdVB) equation. The results of the present investigation may be applicable to some dusty plasma environments, such as dusty plasma existing in polar mesosphere region.

The 3+1 dimensional Kadomtsev–Petviashvili Burgers' equation in non-uniform dusty plasmas

Using the perturbation method, the 3+1 dimensional modified variable coefficient Kadomtsev–Petviashvili (MKP) Burgers' equation governing nonlinear dust acoustic shock waves is derived with the combined effects of non-adiabatic dust charge fluctuation, higher-order transverse perturbation and the non-thermally distributed ions in inhomogeneous dusty plasmas due to spatial gradients of dust charge and plasma densities for the first time. The MKP Burgers' equation is reduced to the standard variable coefficient Kadomtsev–Petviashvili (KP) Burgers' equation. A particular solution of this KP Burgers' equation is also obtained. It is shown that the dust acoustic shock waves can exist in the KP Burgers' equation.

Rayleigh Taylor instability in a dusty plasma

A non-local theory is developed to study the Rayleigh–Taylor instability in an inhomogeneous dusty plasma in the presence of a uniform magnetic field. Using the fluid equations and the dynamics of charged dust grains, an eigenmode equation is derived to study the stability of the mode. Typical space parameters in the vicinity of Saturn are used to investigate the stability of the mode. The growth rate of the Rayleigh–Taylor is found to be drastically higher in a dusty plasma than in a pure plasma. This might have a wider consequence in explaining the origin of low-frequency modes in various situations in the space atmosphere. The effects of the dust charge, and the dust density on the growth rate of the instability are also studied.

Nonlinear Dust-Acoustic Waves in an Inhomogeneous Dusty Plasma With Nonthermal Distribution of Electrons

The propagation of dust-acoustic waves (DAWs) in an inhomogeneous warm dusty plasma consisting of nonthermal electrons, ions, and dust particles is investigated. The inhomogeneity is considered in the equilibrium density of the electrons, ions, and dust particles. Nonlinear DAWs are governed by a Korteweg-de Vries (KdV) type of evolution equation having variable coefficients arising due to density inhomogeneities. The analytical solution of the KdV equation has been obtained by making use of an appropriate set of coordinate transformations. The amplitude of nonlinear DAWs is found to increase with the inclusion of the nonthermal distribution of electrons.

Modified Simon-Hoh Instability in a magnetized inhomogeneous dusty plasma

The modified Simon-Hoh Instability (MSHI) in an inhomogeneous plasma in presence of charged dust grains is investigated where the ions and dust are unmagnetized but electrons are strongly magnetized. Our dispersion relation matches exactly to the dispersion equation (18) of Sakawa et al.15, when we withdraw the contribution of dust grains from our expression. The growth rates of MSHI in presence of dust grains, shows either comparable or lower than that of dust free plasma.

Multidimensional dust acoustic solitary waves in inhomogeneous magnetized dusty plasmas with nonthermal ions

The linear dispersion relation and a modified variable coefficients Korteweg–de Vries (MKdV) equation governing the three-dimensional dust acoustic solitary waves are obtained in inhomogeneous dusty plasmas comprised of negatively charged dust grains of equal radii, Boltzmann distributed electrons and nonthermally distributed ions. The numerical results show that the inhomogeneity, the nonthermal ions, the external magnetic field and the collision have strong influence on the frequency and the nonlinear properties of dust acoustic solitary waves and both dust acoustic solitary holes (soliton with a density dip) and positive solitons (soliton with a density hump) are excited.

Three-dimensional dust acoustic solitary waves in nonuniform magnetized dusty plasmas with adiabatic dust charge fluctuation

Using a standard reductive perturbation theory, a modified variable coefficients Korteweg–de Vries (MKdV) equation governing the three-dimensional dust acoustic solitary waves is derived in inhomogeneous dusty plasmas comprising negatively charged dust grains of equal radii, Boltzmann distributed electrons and ions. The incorporation of the combined effects of adiabatic dust charge fluctuation, the external magnetic field and the inhomogeneity caused by nonuniform equilibrium values of particle density, charging variable and particle potential on the waves leads to a significant modification of the nature of dust acoustic solitary waves and excites both dust acoustic solitary holes (solitons with a density dip) and positive solitons (solitons with a density hump).

The instability of dust acoustic waves in inhomogeneous dusty plasmas with non-adiabatic dust charge fluctuation

This paper investigates the propagation of linear dust acoustic waves in inhomogeneous dusty plasmas due to spatial gradients of dust charge, plasma densities. A linear dispersion relation is obtained with the non-adiabatic dust charge fluctuation and the non-thermally distributed ions. The numerical results show that the inhomogeneity, non-thermal ions and non-adiabatic dust charge fluctuation have strong influence on the frequency and the damping rate of waves.

Effect of dust charge fluctuation on the propagation of dust-ion acoustic waves in inhomogeneous mesospheric dusty plasma

Investigation of positive and negative dust charge fluctuations on the propagation of dust-ion acoustic waves (DIAWs) in a weakly inhomogeneous, collisionless, unmagnetized dusty plasmas consisting of cold positive ions, stationary positively and negatively charged dust particles and isothermal electrons. The reductive perturbation method is employed to reduce the basic set of fluid equations to the variable coefficients Korteweg–de Varies (KdV) equation. At the critical ion density, the KdV equation is not appropriate for describing the system. Hence, a new set of stretched coordinates is considered to derive the modified variable coefficients KdV equation. It is found that the presence of positively charged dust grains does not only significantly modify the basic properties of solitary structure, but also changes the polarity of the solitary profiles. In the vicinity of the critical ion density, neither KdV nor the modified KdV equation is appropriate for describing the DIAWs. Therefore, a further modified KdV equation is derived, which admits both soliton and double layer solutions.

Multidimensional nonlinear dust acoustic shock waves in nonuniform magnetized dusty plasmas with nonadiabatic dust charge fluctuation

The propagation of multidimensional nonlinear dust acoustic shock waves in inhomogeneous dusty plasmas due to spatial gradients of dust charge and plasma densities is investigated. A modified variable coefficients Korteweg–de Vries Burgers equation is derived with the nonadiabatic dust charge fluctuation, the nonthermally distributed ions, dust-neutral collision, and the external magnetic field. The numerical results show that the inhomogeneity, the nonthermal ions and the nonadiabatic dust charge fluctuation have strong influence on the nonlinear properties of dust acoustic shock waves.

Characteristics of dust-ion-acoustic shock in inhomogeneous plasma by WENO scheme simulation

Based on the hydrodynamic equations, the characteristics of nonlinear dust-ion-acoustic shock propagation in an inhomogeneous dusty plasma are numerically studied, by means of the fifth-order weighted essentially non-oscillatory (WENO) finite difference scheme. The inhomogeneous dust charging process for different plasma parameters has been incorporated and its effect on the shock propagation has been investigated. Comparisons of the shocks in the cases of different ion density distributions and different electron-to-ion density ratios are presented. The results show that the dust charging process results in wave damping and dissipation, and the decrease of the electron-to-ion density ratio leads to the increase of the speed, amplitude and width of the shock front. Moreover, the dispersion effect is dominant in the case of sharp shocks whereas the smooth shocks are easily dissipated.

Numerical study of dust-ion-acoustic solitary waves in an inhomogeneous plasma

The hydrodynamic equations describing the propagation of nonlinear dust-ion-acoustic solitary waves in an inhomogeneous dusty plasma are solved numerically, taking into consideration dust charging process. Equilibrium plasma densities and dust charge are assumed to be spatially nonuniform, but dust number density is taken to be uniform. It is shown that wave evolutions depend sensitively on the plasma density distributions and electron-to-ion density ratios. Numerical results show that an initial solitary pulse evolves into a dispersive pulse with an oscillatory tail when the wave propagates from high- into low-density region and whereas the pulse can keep its shape when it propagates in the opposite direction. The dust charging process results in the damping of the solitary pulses.