Dense Dusty Plasmas Research Articles

A Saddle-Node Bifurcation Scenario for Disappearance of Nonlinear Electrostatic Waves in an Ultra-Relativistic Degenerate Dense Plasma

The birth or destruction of electrostatic excitations is investigated in an ultra-relativistic degenerate dense dusty plasma by the saddle-node bifurcation scenario. An abstract form of bifurcation is derived which captures the main features of traveling wave solutions for various regions in the parameter space of plasma number density. We show that a sudden disappearance of solitary and supernonlinear periodic waves occurs at the critical point of saddle-node bifurcation. For a range of ion number density and dust concentration, we obtain the critical values of bifurcation and different existence domains of stability region. The numerical phase portrait analysis is also performed to examine the coexistence of solitary waves, nonlinear periodic, and supernonlinear periodic waves for different conditions. We further derive analytically the conditions with respect to the model parameters that give rise to both polarities of solitary waves. It is found that the amplitude of localized structures decreases with the increase in the plasma number density. Our results could be applicable for astrophysical objects with high density matter such as white dwarfs and neutron stars.

Quantum Effects on Cylindrical Dust-ion Acoustic Waves in a Semiclassical Dense Dusty Plasma

The nonlinear cylindrical dust ion acoustic waves are studied in a collisional unmagnetized dense dusty plasma medium containing inertialess degenerated electrons and positrons, fluid ions, negatively charged dust fluid and neutrals in the background, including exchange-correlation effects of both electrons and positrons. Employing the reductive perturbation method, the damped Kadomstev–Petviashvili equation is derived in the framework of two-dimensional cylindrical geometry. An approximate analytical solution of this equation is also discussed. The quantum and geometrical effects on the dust ion acoustic waves have been investigated. It is found that the dust ion acoustic wave is modified by quantum diffraction, Fermi statistics and exchange-correlation potential. Moreover, it has been found that the nebulon structures of quantum dust ions acoustic wave are formed due to the Cartesian geometry and the transverse perturbation. It is also observed that the nebulon structure is significantly modified by the exchange-correlation effects.

Screening effects in dense Coulomb media: Beyond the Poisson–Boltzmann and Kirkwood approximations

A theoretical approach is proposed that allows giving a suitable description of the equilibrium characteristics of dense heterogeneous Coulomb media, for example, dusty plasma (DP) and ionic colloidal suspensions containing charged particles (grains) of finite size. It is shown that taking into account the Carnahan–Starling closed formula for the contribution of hard spheres of diameter d and number density n into the free energy of DP essentially improves the approximations by Poisson–Boltzmann (ideal gas of point ions) and Kirkwood (ideal gas of finite-sized ions). Thus, in systems like DP, along with the Kirkwood parameter (the ratio of d to the Debye–Hückel screening length), a second independent dimensionless parameter nd3 appears. As a result, for the first time, an opportunity opens up to give a natural explanation of the experimental fact, according to which the screening length in a concentrated electrolyte may turn out to be an increasing function of nd3. Useful evidence of the internal consistency of the theory is that it allows one to give a satisfactory numerical estimate of the dimensionless temperature of DP triple point (vapor–liquid–solid), in agreement with Monte Carlo simulations for concentrated electrolytes like CsCl. Furthermore, the results obtained are in quantitative agreement with a fairly wide set of experimental data on the melting of real ionic crystals (from LiF to CsI and from MgO to BaO) and, thus, provide a theoretical basis for the long-established empirical “similarity rule” that relates melting temperatures to effective ion sizes.

Dust-acoustic solitary and cnoidal waves in a dense magnetized dusty plasma with temperature degenerate trapped electrons and nonthermal ions

A rigorous theoretical study has been made on obliquely propagating dust-acoustic solitary waves (OPDASWs) and cnoidal waves in a dense degenerate dusty plasma medium in the presence of temperature degenerate trapped electrons and κ−nonthermal ion population. A reductive perturbation technique has been adopted to obtain the Zakharov-Kuznetsov (ZK) equation and the modified ZK (mZK) equation. The solitary wave solutions of ZK and mZK equations are obtained to analyse the characteristics of solitary waves in such a plasma. The Jacobi (cn) elliptic periodic wave solution for mZK is also derived to analyse the nature of dust acoustic travelling wave. The different plasma parameters (e.g., electron-to-dust number density via δ, ions nonthermality via κ, temperature effect of degenerate trapped electrons via T, etc.) are seen to have significant inluence on the propagation nature of OPDASWs. The applications of results may be useful to explain/understand the nature of solitary waves in different ultra-dense astrophysical environments (such as neutron stars, white dwarfs etc. [, ]) and also in experiments involve the interaction of laser and solid density plasma and inertial confinement fusion, [, ] in which the relativistic effects play major role.

A minimally invasive electrostatic particle extractor for nanodusty plasmas and its application for the verification of in situ Mie polarimetry

We present an electrostatic particle extractor system (EPEX) which extracts particles from a reactive, particle-growing plasma by using the electrostatic force. The system is able to extract eight samples during a single growth cycle without the need to interrupt the plasma process. Using video microscopy, imaging-Mie, and Mie polarimetry we demonstrate the minimal invasiveness of EPEX. The extraction voltage and its duration are optimized to tune the particle density on the sample wafer. Compared to other invasive extraction methods, EPEX is fast and reliable. Using atomic force microscopy the size of the particles can be determined from samples extracted from the nanodusty plasma during one growth cycle and can be compared to the results of simultaneously performed in situ Mie polarimetry for the first time. We show that the extraction process can be divided in three distinct phases and that its physics can be understood in the simple framework of the force balance for a single dust particle. Using this single particle model, we present a new method for determining the particle charge of dust particles in dense dusty plasmas. The determined particle charge of (−9.2 ± 2.8) elementary charges reveals a strong Havnes effect.

Fluid Dynamical Instabilities in Magnetized Partially Ionized Dense Dusty Plasma

Fluid Dynamical Instabilities in Magnetized Partially Ionized Dense Dusty Plasma

Drift vortices in inhomogeneous collisional dusty magnetoplasma**Project supported by the National Natural Science Foundation of China (Grant Nos. 11365017, 11465015, 11405110, 11305031, and 11404214) and the Technology Landing Project of the Education Department of Jiangxi Province of China (Grant No. KJLD13086).

For the sake of investigating the drift coherent vortex structure in an inhomogeneous dense dusty magnetoplasma, using the quantum hydrodynamic model a nonlinear controlling equation is deduced when the collision effect is considered. New vortex solutions of the electrostatic potential are obtained by a special transformation method, and three evolutive cases of monopolar vortex chains with spatial and temporal distribution are analyzed by representative parameters. It is found that the collision frequency, particle density, drift velocity, dust charge number, electron Fermi wavelength, quantum correction, and quantum parameter are all influencing factors of the vortex evolution. Compared to the uniform dusty system, the vortex solutions of the inhomogeneous system present richer spatial evolution and physical meaning. These results may explain corresponding vortex phenomena and support beneficial references for the dense dusty plasma atmosphere.

Nonlinear Dust Acoustic Waves in Strongly Coupled Quantum Dusty Plasmas

Using a set of fluid equations to describe the inertial dust grain component in dense collisionless unmagnetized quantum dusty plasmas, where the electrons and ions obey the Thomas-Fermi density distribution, the propagation characteristics of dust acoustic solitary waves (DASWs) are studied. First, a linear dispersion of dust acoustic wave (DAW) is obtained, and it is shown that the DAW is modified by a strongly coupled parameter. Then for small amplitude solitary waves, the Korteweg-de Vries equation is obtained by applying the reductive perturbation technique. For arbitrary amplitude solitary waves, the Sagdeev potential method is employed and the Sagdeev potential is analyzed. In both cases, the effect of dust coupling parameters on the characteristics of DASWs in our system are analyzed.

Dense dust structures in cryogenic complex plasma

In the previous researches of cryogenic complex (dusty) plasma [1] we observed experimentally complex plasma systems formed in cryogenic environments. Particularly it was revealed from the experiments that dust structures with high concentration of macroparticles can be formed. So-called super dense dusty plasma structures in which interparticle distance is comparable with particle size were also observed. Thus concentration of particles was close to concentration of background plasma. Similar formations had unusual properties (sphere-like form, free boundaries, etc.) and represent new object in dusty plasma researches. In the present work new results on experimental investigations of dense dust structures at cryogenic temperatures were presented. The experiments were made by means of recently developed techniques and cryogenic facilities (optical cryostat). Possible nature of the unusual properties of super dense dusty plasma structures was discussed.

Externally excited planar dust acoustic shock waves in a strongly coupled dusty plasma under microgravity conditions

The formation and dissipation of an externally excited planar dust acoustic shock wave in a three-dimensional uniform dust cloud has been observed under microgravity conditions. The experiment has been performed in the dc gas discharge chamber ‘Plasma Kristall-4’ (Fortov et al 2005 Plasma Phys. Control. Fusion 47 B537) on board the A300 Zero-G airplane. The shock Mach number and compression factor reached 3.5 and 6, correspondingly, with a shock width of about the interparticle distance. Due to the utilization of the polarity-switching dc discharge mode and application of the Rankine–Hugoniot relations, the dust particle electrostatic pressure was determined and the Hugoniot percussive adiabat for the dust subsystem was derived. The obtained data were simulated using thermodynamic properties of highly nonideal Debye–Hückel (Yukawa) systems. Comparison of the experimental and simulated data has demonstrated that the screening length in a dense dusty plasma is not determined by the total ion number density, but rather by those ‘effective’ ions which are not bounded by negatively charged dust grains. Thus, this work presents a new experimental approach for the investigation of the dense dusty plasma clouds.

Oblique collision effects on nonlinear quantum dust-acoustic solitary waves in magnetized dense dusty plasmas

The oblique collision of nonlinear quantum dust-acoustic (NQDA) solitary waves in a three-dimensional (3D) magnetized dense dusty plasma is investigated. Furthermore, two coupled Kortwege–de Vries equations for describing our model and the analytical phase shifts after the oblique collision of two NQDA solitary waves are derived using the extended Poincare–Lighthill–Kuo (PLK) method. The modification in the phase shift and the trajectory of the NQDA solitary waves structures due to the inclusion of oblique collision and external magnetic field are discussed numerically. The numerical results are applied to high density astrophysical situations such as in superdense white dwarfs.

Arbitrary amplitude solitary and shock waves in an unmagnetized quantum dusty electron-positron-ion plasma

The behavior of quantum dust ion acoustic soliton and shocks in a plasma including inertialess quantum electrons and positrons, classical cold ions, and stationary negative dust grains are studied, using arbitrary amplitude approach. The effect of dissipation due to viscosity of ions is taken into account. The numerical analysis of Sagdeev potential for small value of quantum diffraction parameter (H) shows that for chosen plasma, only compressive solitons can exist and the existence domain of this type of solitons is decreased by increasing dust density (d). Additionally, the possibility of propagation of both subsonic and supersonic compressive solitons is investigated. It is shown that there is a critical dust density above which only supersonic solitons are observed. Moreover, increasing d leads to a reduction in the existence domain of compressive solitons and the possibility of propagation of rarefactive soliton is provided. So, rarefactive solitons are observed only due to the presence of dust particles in this model quantum plasma. Furthermore, numerical solution of governed equations for arbitrary amplitude shock waves has been investigated. It is shown that only compressive large amplitude shocks can propagate. Finally, the effects of plasma parameters on these structures are investigated. This research will be helpful in understanding the properties of dense astrophysical (i.e., white dwarfs and neutron stars) and laboratory dusty plasmas.

Non‐Ideal Dust Structures in Cryogenic Complex Plasmas

AbstractThe possibility of the formation of dust structures in cryogenic environment at 4.2‐77 K was proved experimentally in the previous researches of cryogenic complex (dusty) plasma [1–5]. It was revealed from the experiments, among others, that the dust structures with high concentration of dust particles can be formed, in which interparticle distance is comparable with particle size ‐ super dense dusty plasma structures. Such structures had exotic properties such as globular (spherical) form, free boundaries, etc. In the present work new results on the experimental investigations of new phenomenon of spheroidizing ‐ process of the dust structure transition to compact globular shape at cryogenic temperatures ‐ were presented. Possible nature of such phenomenon is discussed (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Double-wells and double-layers in dusty Fermi–Dirac plasmas: Comparison with the semiclassical Thomas–Fermi counterpart

Based on the quantum hydrodynamics (QHD) model, a new relationship between the electrostatic-potential and the electron-density in the ultradense plasma is derived. Propagation of arbitrary amplitude nonlinear ion waves is, then, investigated in a completely degenerate dense dusty electron-ion plasma, using this new energy relation for the relativistic electrons, in the ground of quantum hydrodynamics model and the results are compared to the case of semiclassical Thomas–Fermi dusty plasma. Based on the standard pseudopotential approach, it is remarked that the Fermi–Dirac plasma, in contrast to the Thomas–Fermi counterpart, accommodates a wide variety of nonlinear excitations such as positive/negative-potential ion solitary and periodic waves, double-layers, and double-wells. It is also remarked that the relativistic degeneracy parameter which relates to the mass-density of plasma has significant effects on the allowed matching-speed range in Fermi–Dirac dusty plasmas.

Arbitrary amplitude solitary waves and double layers in an ultra-relativistic degenerate dense dusty plasma

Arbitrary amplitude solitary waves (SWs) and double layers (DLs) in an ultra-relativistic degenerate dense dusty plasma (containing ultra-relativistic degenerate ultra-cold electron fluid, inertial ultra-cold ion fluid, and negatively charged static dust) have been investigated by the pseudo-potential approach. It has been found that for δ = 1 (where δ is the ratio of nonlinear wave speed to linear wave phase speed) extremely large amplitude DLs with negative potential exist for μ = 0.537 (where μ is the ratio of dust charge density to ion charge density) and SWs with negative potential exist for 1 > μ > 0.537 . It is also shown that for δ > 1 only SWs with positive potential exist for 0 ⩾ μ < 0.537 , but SWs with positive potential coexist with SWs or DLs with a negative potential for 0.537 > μ > 0.851 . The implications of our results in some compact astrophysical objects, particularly, in white dwarfs and neutron stars, have been briefly discussed.

On the formation of shock and soliton in a dense quantum dusty plasma with cylindrical geometry

Excitation of nonlinear waves in a quantum dusty plasma with various effects is analyzed when the geometry is cylindrical.This introduces the effect of finite boundary conditions on the solitary waves so generated. it is observed that the nonlinear equation deduced is cylindrical KP–Burger type leading to the generation of Shock Wave. Different situations which arises in various parameter regions are considered separately and the form of the nonlinear excitations are obtained explicitly.

Parametric study of nonlinear electrostatic waves in two-dimensional quantum dusty plasmas

The nonlinear properties of two-dimensional cylindrical quantum dust-ion-acoustic (QDIA) and quantum dust-acoustic (QDA) waves are studied in a collisionless, unmagnetized and dense (quantum) dusty plasma. For this purpose, the reductive perturbation technique is employed to the quantum hydrodynamical equations and the Poisson equation, obtaining the cylindrical Kadomtsev–Petviashvili (CKP) equations. The effects of quantum diffraction, as well as quantum statistical and geometric effects on the profiles of QDIA and QDA solitary waves are examined. It is found that the amplitudes and widths of the nonplanar QDIA and QDA waves are significantly affected by the quantum electron tunneling effect. The addition of a dust component to a quantum plasma is seen to affect the propagation characteristics of localized QDIA excitations. In the case of low-frequency QDA waves, this effect is even stronger, since the actual form of the potential solitary waves, in fact, depends on the dust charge polarity (positive/negative) itself (allowing for positive/negative potential forms, respectively). The relevance of the present investigation to metallic nanostructures is highlighted.

Arbitrary amplitude dust ion acoustic solitary waves in dense Fermi plasmas

The arbitrary amplitude dust ion acoustic solitary waves are investigated in unmagnetized quantum plasmas. The quantum hydrodynamic model is employed with the Sagdeev potential approach to describe the nonlinear dust ion acoustic waves in dense Fermi plasmas. It is found that electron density dip structures are formed in the subsonic as well as in the supersonic regions in such dense dusty plasmas. The range of wave Mach number is increased with the increase in the static dust density in quantum plasmas. Both the wave amplitude and width of the nonlinear structure are affected by static dust density. The quantum parameter effects only the width of the nonlinear structure. The amplitude of dust ion acoustic solitary wave is reduced with the increase in the wave Mach number.

A Note on the Possibility of Generating a Dense Dusty Plasma Liquid

Recently, there has been interest in the properties of strongly coupled dusty plasmas in the liquid phase. Here, we consider theoretically a possible way to generate and detect a dense dusty plasma liquid. The idea is to use noble metal submicron dust particles and detect the dust by scattering at the surface plasmon resonance frequency of the dust. Parameters that may be relevant to possible laboratory dusty plasma experiments are discussed.

Response to “Comment on ‘Dust electro-acoustic and Coulomb modes in dense dusty plasmas’ ” [Phys. Plasmas 9, 4416 (2002)

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