Space Dusty Plasmas Research Articles

Dust-acoustic Gardner solitons and double layers in dusty plasmas with nonthermally distributed ions of two distinct temperatures

A rigorous theoretical investigation has been performed on dust-acoustic (DA) solitary structures in an unmagnetized dusty plasma, consisting of negatively charged mobile dust grains, Boltzmann distributed electrons, and nonthermally distributed ions of two distinct temperatures. The Korteweg-de Vries (K-dV), modified K-dV (mK-dV) and Gardner equations, and their solitary waves (SWs) and double layer (DL) (in case of Gardner equation) solutions are derived by using the reductive perturbation technique. The basic features of the DA Gardner solitons (GSs) and DLs are studied analytically as well as numerically. It has been observed that the GSs significantly differ from K-dV and mK-dV solitons, and only positive potential DLs exist in the system. It is also studied that two-temperature nonthermal ions significantly modify the nature and basic properties of the DA SWs. The present investigation can be very effective for understanding and studying the nonlinear characteristics of the DA waves in laboratory and space dusty plasmas.

Obliquely propagating dust-acoustic solitary waves in magnetized dusty plasmas with two-temperature Maxwellian ions

The nonlinear propagation of dust-acoustic waves in an obliquely propagating magnetized dusty plasma, containing Maxwellian distributed ions of distinct temperatures (namely lower and higher temperature Maxwellian ions), negatively charged mobile dust grains, and Maxwellian electrons, is rigorously investigated and analyzed by deriving the Zakharov-Kuznetsov equation. It is investigated that the characteristics of the dustacoustic solitary waves are significantly modified by the external magnetic field, relative ion and electron temperature-ratio, and respective number densities of two population of ions. The implications of the results obtained from this analysis in space and laboratory dusty plasmas are briefly discussed.

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.

Multi-dimensional instability of dust-acoustic solitary waves in a magnetized plasma with opposite polarity dust

Dust-acoustic (DA) solitary structures and their multi-dimensional instability in a magnetized dusty plasma (containing inertial negatively and positively charged dust particles, and Boltzmann electrons and ions) have been theoretically investigated by the reductive perturbation method, and the small-k perturbation expansion technique. It has been found that the basic features (polarity, speed, height, thickness, etc.) of such DA solitary structures, and their multi-dimensional instability criterion or growth rate are significantly modified by the presence of opposite polarity dust particles and external magnetic field. The implications of our results in space and laboratory dusty plasma systems have been briefly discussed.

Dust acoustic shock waves in suprathermal dusty plasma in the presence of ion streaming with dust charge fluctuations

Dust acoustic (DA) shock waves are investigated in a dusty plasma having a high-energy-tail electron distribution. The effects of ion streaming, charge variation and electron deviation from the Maxwellian distribution on the DA shock wave are then considered. It is shown that as the suprathermal character of the plasma is increased, the potential amplitude enhances. It is also found that the ion temperature may be destructive for the formation of DA shock waves. Their strength decreases with increasing ion streaming speed. Our results may be useful in understanding the basic nonlinear features of the DA wave propagation that may occur in space dusty plasmas, especially those including a relative motion between species (comet tails, solar wind streams, etc.).

Dust-acoustic waves and stability in the permeating dusty plasma. II. Power-law distributions

The dust-acoustic waves and the stability theory for the permeating dusty plasma with power-law distributions are studied by using nonextensive q-statistics. In two limiting physical cases, when the thermal velocity of the flowing dusty plasma is much larger than, and much smaller than the phase velocity of the waves, we derived the dust-acoustic wave frequency, the instability growth rate, and the instability critical flowing velocity. As compared with the formulae obtained in part I [Gong et al., Phys. Plasmas 19, 043704 (2012)], all formulae of the present cases and the resulting plasma characteristics are q-dependent, and the power-law distribution of each plasma component of the permeating dusty plasma has a different q-parameter and thus has a different nonextensive effect. Further, we make numerical analyses of an example that a cometary plasma tail is passing through the interplanetary space dusty plasma and we show that these power-law distributions have significant effects on the plasma characteristics of this kind of plasma environment.

Dust acoustic waves in a collisional strongly coupled dusty plasmas

Progress in understanding the nonlinear features of dust-acoustic waves (DAWs) which accompany a collisional strongly and weakly coupled unmagnetized dusty plasma with Boltzmann distributed electrons, ions and negatively charged dust grains is presented. By using a hydrodynamic model, the Korteweg–de Vries-Burgers (KdV-Burgers) equation is derived. The existence regions of the solitary pulses are defined precisely. Furthermore, numerical calculations reveal that, due to collisions, the DAWs damp waves and the damping rate of the waves depends mainly on the collision frequency. The collisions are found to significantly change the basic properties of the DAWs. The effects of electron-to-ion concentration ratio, and ion-to-electron temperature ratio have important roles in the behavior of the DAWs. The results may have relevance in space and laboratory dusty plasmas.

Dust-ion-acoustic solitary waves in a dusty plasma with arbitrarily charged dust and non-thermal electrons

AbstractThe dust-ion-acoustic solitary waves (DIA SWs) in an unmagnetized dusty plasma containing non-thermal electrons, cold mobile positive ions, and stationary arbitrarily (positively and negatively) charged static dust have been theoretically studied. The reductive perturbation technique has been employed to derive the Korteweg-de Vries equation, which admits SW solutions under certain conditions. It has been also shown that the basic features (amplitude, width, speed, etc.) of DIA SWs are significantly modified by the polarity of dust and non-thermal electrons. The implications of our results in space and laboratory dusty plasma situations are briefly discussed.

Arbitrary amplitude dust-acoustic double-layers in an electron-depleted dusty plasma with two high-energy tail ion distributions

AbstractArbitrary amplitude dust-acoustic double-layers (DA-DLs) in two high-energy tail ion distributions are investigated. The electron number density has been assumed sufficiently depleted during the charging of dust grains on account of the attachment of background plasma electrons on the surface of dust grains. It is found that under certain conditions DA-DLs may be admitted. The degree of suprathermality of the low-temperature component has a sensitive role on their formation and a small change in this degree can even prevent the DL formation. The ‘Maxwellianization’ of the high-temperature component involves a suprathermalization process of the low-temperature component for the existence of localized DA-DLs. Our results may be relevant to a number of space dusty plasma systems, particularly the Saturn's F-ring where electron depletion and suprathermality are thought to come into play.

Dust-acoustic waves in strongly coupled dusty plasmas with nonextensive electrons and ions

The nonlinear features of dust-acoustic waves in a strongly coupled unmagnetized dusty plasma containing electrons and ions following q-nonextensive distribution, and negatively charged mobile dust are investigated by using the reductive perturbation method. The effects of important parameters, such as the q-parameter, temperature, density, and velocity on the properties of solitary and shock waves are discussed. The conditions for the formation of solitary structures and monotonic and oscillatory shock structures are also found. The implications of our result in space and laboratory dusty plasmas are discussed.

Nonlinear evolution of the lower hybrid irregularities in artificially created dusty space plasmas

Plasma turbulence associated with the creation of an artificial dust layer in the earth's ionosphere is investigated. The lower hybrid turbulence is considered as the dust is injected across the geomagnetic field into the background plasma, which generates irregularities at times much longer than the dust charging period. A two‐dimensional hybrid particle‐in‐cell model is developed to investigate the lower hybrid instability driven by the streaming charged dust beam. It is shown that turbulence near the lower hybrid frequency is generated which has spatial structure with enhanced electric fields in localized density depletions. The wave saturation involves ion and dust heating. Energization of ions perpendicular to the magnetic field is observed. The ratio of electron plasma frequency to electron gyro frequency plays an important role on the lower hybrid irregularity spatial structure. Important parameters of the dust cloud that impact nonlinear evolution of the waves are discussed for the regimes of upcoming space experiments. Similarities between past observations of lower hybrid turbulence observed during passive space experiments in the auroral region and lower hybrid turbulence generated by such active experiments is discussed.

Dust ion-acoustic solitary waves in a dusty plasma with nonextensive electrons

The dust-modified ion-acoustic waves of Shukla and Silin are revisited within the theoretical framework of the Tsallis statistical mechanics. Nonextensivity may originate from correlation or long-range plasma interactions. Interestingly, we find that owing to electron nonextensivity, dust ion-acoustic (DIA) solitary waves may exhibit either compression or rarefaction. Our analysis is then extended to include self-consistent dust charge fluctuation. In this connection, the correct nonextensive electron charging current is rederived. The Korteweg-de Vries equation, as well as the Korteweg-de Vries-Burgers equation, is obtained, making use of the reductive perturbation method. The DIA waves are then analyzed for parameters corresponding to space dusty plasma situations.

Non-planar Gardner double layers in two-ion-temperature dusty plasma

AbstractNon-planar (cylindrical and spherical) double layers (DLs) in two-ion-temperature dusty plasma, whose constituents are inertial negative dust, ions with two distinctive temperatures, and Boltzmann electrons, are studied by employing the reductive perturbation method. The modified Gardner equation describing the nonlinear propagation of dust-acoustic (DA) waves is derived, and its non-planar double layer solutions are analyzed numerically. The parametric regimes for the existence of DA DLs, which are found to be associated with positive potential only, are obtained. The basic features of non-planar DA DLs, which are found to be different from planar ones, are also identified. The implications of our results to different space and laboratory dusty plasma situations are discussed.

Dromion in space and laboratory dusty plasma

The nonlinear evolution of dust acoustic wave in magnetized dusty plasma was shown to obey the Davey-Stewartson I equation, which admits the so called dromion solutions.

Nonlinear Evolution of the Dust Acoustic Instability in Artificially Created Dusty Space Plasmas

A 2-D hybrid electrostatic model is used to investigate the dust acoustic instability driven by an ion beam. To understand the generation and the nonlinear electrostatic waves, we investigate possible parameter regimes for the dust acoustic instability. The principal application involves the Charged Aerosol Release Experiment in the ionosphere, but also potential applications are for the planetary ring system of Saturn. The plasma background ions and charged dust are treated as discrete particles, whereas electrons are dealt with as a Boltzmann fluid. A Monte Carlo collision model is adopted to deal with the ion-neutral collisions. The kinetic dispersion relation is numerically solved to investigate effects of the ion drift velocity and the dust charge and density on the wave growth rate and the wave propagation direction. The simulation results agree with linear analysis of the instability, which also shows that the most unstable dust acoustic wave may obliquely propagate to the streaming direction. This may be important for radar diagnostics. The wave saturates by trapping dust. The waves damp out as the ion-neutral collision frequency increases comparable with the wave growth rate, and more importantly, such collision may lead to unstable waves propagating even further off the streaming direction.

Multidimensional instability of dust ion-acoustic solitary waves in a magnetized dusty electronegative plasma

AbstractBasic features of obliquely propagating dust ion-acoustic (DIA) solitary waves, and their multidimensional instability in a magnetized dusty electronegative plasma (DENP) containing Boltzmann electrons, Boltzmann negative ions, adiabatic mobile positive ions, and negatively charged stationary dust have been theoretically investigated by reductive perturbation method and small-k perturbation expansion technique. The combined effects of ion adiabaticity, external magnetic field (obliqueness), and negatively charged dust, which are found to significantly modify the basic properties (speed, amplitude, width, and instability) of small but finite-amplitude DIA solitary waves, are explicitly examined. It is also found that the instability criterion and the growth rate of unstable perturbation are significantly modified by the external magnetic field, the propagation directions of both the nonlinear waves, and their perturbation modes. The implications of our results in space and laboratory dusty plasmas are briefly discussed.

Quantum modification of dust shear Alfvén wave in plasmas

The low frequency, long wavelength electromagnetic waves, viz., shear Alfvén waves in quantum dusty magnetoplasmas, have been examined using quantum magnetohydrodynamic model. The magnetized electrons and ions, quantized electrons and magnetized/unmagnetized dust give rise to a modified dispersion relation of the shear Alfvén wave. This modification is significant which is also depicted through graphical representation. The importance and relevance of the present work to the space dusty plasma environments is also pointed out.

Nonplanar dust-ion-acoustic double layers in a dusty nonthermal plasma

[1] The possibility for the formation of the dust-ion-acoustic (DIA) double layers (DLs) in a four-component dusty nonthermal plasma (containing nonthermal electrons, inertial ions, and stationary positively as well as negatively charged dust) has been theoretically investigated by deriving a modified Gardner (MG) equation. The latter has been numerically analyzed in order to identify the basic features of the nonplanar (cylindrical and spherical) DIA DLs. The DIA DLs (that are shown to be associated only with negative potential) have been found to exist for a suitable value of α or μ, where α (μ) is the parameter determining the number of nonthermal electrons (net dust charge density) in the plasma system under consideration. The implications of our results in some space dusty plasma environments have been discussed.

Dusty space plasma diagnosis using temporal behavior of polar mesospheric summer echoes during active modification

Abstract. The objective of this paper is to study the effect of different plasma and dust parameters on Polar Mesospheric Summer Echoes (PMSE) temporal behavior after turn-on and turn-off of radio wave heating and to use these responses to diagnose the properties of the dust layer. The threshold radar frequency and dust parameters for the enhancement or suppression of radar echoes after radio wave heating turn-on are investigated for measured mesospheric plasma parameters. The effect of parameters such as the electron temperature enhancement during heating, dust density, dust charge polarity, ion-neutral collision frequency, electron density and dust radius on the temporal evolution of electron irregularities associated with PMSE are investigated. The possible diagnostic information for various charged dust and background plasma quantities using the temporal behavior of backscattered radar power in active experiments is discussed. The computational results are used to make predictions for PMSE active modification experiments at 7.9, 56, 139, 224 and 930 MHz corresponding to existing radar facilities. Data from a 2009 VHF (224 MHz) experiment at EISCAT is compared with the computational model to obtain dust parameters in the PMSE.

Nonplanar double layers in plasmas with opposite polarity dust

Nonplanar (cylindrical and spherical) double layers (DLs) in a four-component dusty plasma (composed of inertial positively and negatively charged dust, Boltzmann electrons and ions) are studied by employing the reductive perturbation method. The modified Gardner equation describing the nonlinear propagation of the dust-acoustic (DA) waves is derived, and its nonplanar double layer solutions are numerically analyzed. The parametric regimes for the existence of the DLs, which are found to be associated with positive potential only, are obtained. The basic features of nonplanar DA DLs, which are found to be different from planar ones, are also identified. The implications of our results to different space and laboratory dusty plasma situations, where opposite polarity dust are observed, are discussed.