Dust Charge Variation Research Articles

The effect of elementary reactions on solitary waves in dusty plasmas

The conditions of existence of solitons have been determined by Wang et al. [Phys. Lett. A 339, 96 (2005)], in negative ions containing dusty plasmas where Boltzmannian ions and electrons are assumed. The study is revisited taking into account actual elementary reactions in plasma conditions, viz., particles attachment by grains as well as neutrals and electron impact ionization of neutrals. Dust charge variation is self-consistently introduced leading to the Boltzmannian approximation relaxation.

Dust Acoustic Wave in Dusty Plasmas With Streaming Ions Under Ultraviolet Irradiation

The reductive perturbation method is applied to investigate the dust acoustic soliton in dusty plasmas with streaming ions under ultraviolet irradiation theoretically and numerically. The self-consistent dust charge variation is taken into account. It is shown that the ultraviolet irradiation can significantly lower the magnitude of the dust negative charge, and ion streaming velocity firstly raise the magnitude of the dust negative charge and then lower it. With the growth of (Ultraviolet) UV photo flux or ion streaming velocity, the phase velocity and width of the solitary waves decrease, whereas its amplitude increases.

Low-frequency wave modulations in an electronegative dusty plasma in the presence of charge variations

The effects of dust charge variations on low-frequency wave modulations in an electronegative dusty plasma are investigated. The dynamics of the modulated wave is governed by a nonlinear Schrödinger equation with a dissipative term. The dissipation arises due to the nonsteady (nonadiabatic) dust charge variations. Theoretical and numerical investigations predict the formation of dissipative bright (envelope) and dark solitons. The nonsteady charge-variation-induced dissipation reduces the modulational instability growth rate and introduces a characteristic time scale to observe bright solitons. Results are discussed in the context of electronegative dusty plasma experiments.

Nonlinear dust acoustic waves in a charge varying complex plasma with nonthermal ions featuring Tsallis distribution

The concept of ion nonthermality is generalized within the theoretical framework of the Tsallis thermostatistics. In this connection, a physically meaningful ion distribution function is outlined. As the nonextensive character of the nonthermal ions increases, the distribution shoulders may become less or more prominent and high energy states are less or more probable than in the extensive nonthermal case. Variable charge dust acoustic waves are then addressed. We first consider the case of adiabatic dust charge variation and discuss later the case when the nonadiabatic charge variations are self-consistently included. Our results may complement and provide new insight into previously published work in nonthermal space plasmas.

Similaritons and their interactions in collisional dusty plasmas with variable dust charge and nonthermal ions

In this paper, a damped nonlinear Schrödinger equation governing dust acoustic solitary waves is obtained in collisional dusty plasmas being comprised of dust grains with dust charge variation, Boltzmann distributed electrons and nonthermally distributed ions. The modulation instability (MI) of dust-acoustic waves is studied and the expression of the MI growth rate is given. The numerical results show that the nonthermal ions, collision effect and ion-to-electron temperature ratio have a strong influence on the existential region of different types of similaritons and the amplitude of similaritons. Furthermore, the different interactions of two similaritons are investigated.

Dust particle charge in plasma with ion flow and electron depletion near plasma boundaries

The charge on micrometer-sized dust particles suspended in plasma above the powered electrode of radio-frequency discharges is studied. Using a self-consistent fluid model, the plasma profiles above the electrode are calculated and the electron depletion towards the electrode, as well as the increasing flow speed of ions toward the electrode are considered in the calculation of the dust particle floating potential. The results are compared with those reported in literature and the importance of the spatial dust charge variation is investigated.

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.

Nonextensive electron and ion dust charging currents

The correct nonextensive electron and ion charging currents are presented for the first time based on the orbit motion limited approach. For −1<q<1, where q measures the amount of plasma nonextensivity, the nonextensive electron charging current is expressed in terms of the hypergeometric function. The variable dust charge is expressed in terms of the Lambert function and we take advantage of this transcendental function to investigate succinctly the effects of nonextensive charge carriers. The obtained formulas bring a possibility to build theories on nonlinear collective process in variable charge nonextensive dusty plasmas.

Three-dimensional stability of dust-ion acoustic solitary waves in a magnetized multicomponent dusty plasma with negative ions

Using the small-k expansion perturbation method, the three-dimensional stability of dust-ion acoustic solitary waves (DIASWs) in a magnetized multicomponent dusty plasma containing negative heavy ions and stationary variable-charge dust particles is analyzed. A nonlinear Zakharov–Kuznetsov equation adequate for describing these solitary structures is derived. Moreover, the basic features of the DIASWs are studied. The determination of the stability region leads to two different cases depending on the oblique propagation angle. In addition, the growth rate of the produced waves is estimated. The increase of either the negative ion number density or their temperatures or even the number density of the dust grains results in reducing the wave growth rate. Finally, the present results should elucidate the properties of DIASWs in a multicomponent plasma with negative ions, particularly in laboratory experiment and plasma process.

Semi-analytical study of variable charge dust acoustic solitary waves in a dusty plasma with a q-nonextensive ion velocity distribution

An attempt is made to study variable charge dust acoustic (DA) solitons within the theoretical framework of the Tsallis statistical mechanics. The correct nonextensive ion charging current is presented for the first time based on the orbit motion limited (OML) approach. The variable dust charge is then expressed in terms of the Lambert function and we take advantage of this transcendental function to investigate nonlinear localized DA waves in a charge varying dusty plasma with nonextensive ions more rigorously. Our results reveal that the ion nonextensivity makes the dust acoustic solitary structure more spiky. As the ions deviate from their thermodynamic equilibrium, the dust grain charge becomes least negative and the dust accumulation more effective. In addition, the nonextensive character of the ions contributes to the electron depletion. The latter is more pronounced as the ions evolve far away from their thermal equilibrium. Our results should help in providing a good fit between theoretical and experimental results.

Dust-acoustic shock formation in adiabatic hot dusty plasmas with variable charge

Shocklike structure can be formed after a certain transient time due to the self-steepening of the negative potential. In order to have a monotonic or oscillatory shock wave, it is known that a source of dissipation is needed. In this study, we considered the variation of dust charge as a source of dissipation. By using the reductive perturbation technique, the nonlinear Burgers equation is derived and the shocklike solution is determined. The effects of dust temperature on different characteristics of dust-acoustic shock structure are discussed. It is found out that the dust thickness is not affected by dust temperature. By considering a dusty plasma system with a set of parameters, it is shown that there exists a specific dust critical temperature Tdc which gives maximum height for the dust-acoustic shock structure. The effects of the plasma species temperature on shock formation are also investigated.

The effects of nonadiabatic dust charge variation and ultraviolet irradiation on the modulational instability of dust ion acoustic waves

The effects of nonadiabatic dust charge fluctuation on the nonlinear propagation of the dust ion acoustic (DIA) waves in the dusty plasma with positively charged dust grains have been investigated. By using the reductive perturbation technique, a three-dimensional modified nonlinear Schrödinger equation (mNLSE) governing the nonlinear envelope DIA waves was derived and the approximate solitary wave solution of the mNLSE was also obtained in the weak effect of nonadiabatic dust charge fluctuation limit, which shows that the amplitude of the DIA solitary wave exponentially decreases with time due to the collisionless dissipation caused by the nonadiabatic dust charge variation. The frequency, instability growth rate, and the critical modulational wave number of the small amplitude modulation are all dependent on photoelectron generated by ultraviolet irradiation and time due to the presence of nonadiabatic dust charge variation. The transverse perturbation plays an important role in the modulational instability region.

Effect of superthermal electrons on Alfvén wave propagation in the dusty plasmas of solar and stellar winds

The dispersive characteristics and absorption coefficient of Alfvén waves propagating parallel to the ambient magnetic field are discussed, taking into account the effects of both the charged dust particles present in the interplanetary medium and the superthermal character of the electron distribution function, using physical parameters relevant for solar and stellar winds. The solar wind electrons are described by an isotropic κ distribution and the protons are described by a Maxwellian. The results are valid for a frequency regime well above the dust‐plasma and dust‐cyclotron frequencies. However, the theoretical formulation is fully kinetic and the dust charge variation is taken into account. The charging process of the dust is assumed to be associated with the capture of electrons and ions by the dust particles during inelastic collisions with the plasma particles. The dispersion relation for parallel‐propagating Alfvén waves is numerically solved and the solutions are compared with particular situations where either the dust particles are absent or the electrons are described by a Maxwellian. It is shown that the presence of both the charged dust particles and the superthermal character of the electron distribution function sensibly modify the dispersion relation of low‐frequency and long‐wavelength Alfvén waves and significantly increase the absorption coefficient, strongly suggesting that both effects are equally important for a realistic description of the physical processes that occur in solar and stellar winds and that are influenced by the Alfvén waves, such as the energization of particles and the turbulent cascade of magnetic fluctuations.

Dust acoustic solitary and shock waves in coupled dusty plasmas with variable dust charge and vortex-like ion distribution

The modified Kodomtsev-Petviashvili-Burger (mKP-Burger) and Kodomtsev-Petviashvili-Burger equations are derived in strongly coupled dusty plasmas containing iso-nonthermal ions; Boltzmann distributed electrons and variable dust charge. We use reductive perturbation method and discuss on solitary waves and shock waves solutions of these equations.

Modified KP-Burger and KP-Burger equations in coupled dusty plasmas with variable dust charge and non-isothermal ions

The modified Kodomtsev-Petviashvili-Burger (mKP-Burger) and Kodomtsev-Petviashvili-Burger equations are derived in strongly coupled dusty plasmas containing non-isothermal ions, Boltzmann distributed electrons and variable dust charge. We use reductive perturbation method and discuss on solitary waves and shock waves solutions of these equations.

Nonlinear dust acoustic waves in a charge varying dusty plasma with suprathermal electrons

Arbitrary amplitude dust acoustic waves in a dusty plasma with a high-energy-tail electron distribution are investigated. The effects of charge variation and electron deviation from the Boltzmann distribution on the dust acoustic soliton are then considered. The dust charge variation makes the dust acoustic soliton more spiky. The dust grain surface collects less electrons as the latter evolves far away from their thermodynamic equilibrium. The dust accumulation caused by a balance of the electrostatic forces acting on the dust grains is more effective for lower values of the electron spectral index. Under certain conditions, the dust charge fluctuation may provide an alternate physical mechanism causing anomalous dissipation, the strength of which becomes important and may prevail over that of dispersion as the suprathermal character of the plasma becomes important. Our results may explain the strong spiky waveforms observed in auroral plasmas.

On the possibility of collective attraction in complex plasmas

An investigation on the possible collective electric attraction between like-charged dust particles has been performed in an isotropic homogeneous complex (dusty) plasma in which a balance between plasma creation due to ionization and plasma loss due to the absorption on dust particles has been reached. The analysis is made on the basis of a self-consistent fluid model, which includes plasma ionization, plasma loss on dust particles, dust charge variations, and ion-neutral friction. It is shown that the interaction potential can have an attractive part in the stability regime of the ionization-absorption balance with respect to ion perturbations only under very limited circumstances.

Dust acoustic solitary waves in a charge varying relativistic dusty plasma

The problem of nonlinear variable charge dust acoustic solitary waves in dusty plasma with relativistic electrons and ions is addressed. The appropriate relativistic charging currents, derived within the theoretical framework of the orbit-limited motion theory, are used. Our results show that in such a plasma, rarefactive spatially localized dust acoustic waves can exist. Their spatial patterns are significantly modified by the relativistic effects. In particular, it may be noted that relativistic effects make the solitary structure spikier. Our results should help to understand the salient features of coherent nonlinear structures that may occur in relativistic space plasmas.

Variable charge dust acoustic solitary waves in a dusty plasma with a q-nonextensive electron velocity distribution

A first theoretical work is presented to study variable charge dust acoustic solitons within the theoretical framework of the Tsallis statistical mechanics. Our results reveal that the spatial patterns of the variable charge solitary wave are significantly modified by electron nonextensive effects. In particular, it may be noted that for −1<q<1 (where q stands for the electron nonextensive parameter) the soliton pulse amplitude increases while its width is narrowed as q→1. As the electrons deviate from their thermodynamic equilibrium, the dust grain charge Qd becomes more negative and the dust grains localization (accumulation) less pronounced. The electrons are locally expelled and pushed out of the region of the soliton’s localization. This electron depletion becomes less effective as the electrons evolve far away from their thermal equilibrium. The case q>1 provides qualitatively opposite results: electron nonextensivity makes the solitary structure more spiky. Our results should help in providing a good fit between theoretical and experimental results.

Kadomstev-Petviashvili (KP) equation in warm dusty plasma with variable dust charge, two-temperature ion and nonthermal electron

In this work, the propagation of nonlinear waves in warm dusty plasmas with variable dust charge, two-temperature ion and nonthermal electron is studied. By using the reductive perturbation theory, the Kadomstev-Petviashvili (KP) equation is derived. The energy of the soliton and the linear dispersion relation are obtained. The effects of variable dust charge on the energy of soliton and the angular frequency of linear wave are also discussed.