On the Characteristics of Wave Propagation in a Magnetized Dusty Plasma with Streaming of Electrons and Ions

Propagation of waves in a magnetized dusty plasma are studied for all the range of values of ion-cyclotron frequency, and having streams of electrons and ions. The dispersion relation is obtained for the waves propagating through the dusty plasma and analysed for different modes of propagation for relative abundance of dust in the plasma. It is observed that abundance of dust, streaming motions of electrons and ions have an important influence on the propagation of waves in the dusty plasma particularly when the phase velocity of the wave is in the low frequency region. This revised version was published online in July 2006 with corrections to the Cover Date.     

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.     

Weakly nonlinear dust ion- acoustic double- layers in a dusty plasma with nonextensive electrons

Weak dust ion-acoustic (DIA) double- layers (DLs) in a dusty plasma with nonextensive electrons are addressed. A generalized Korteweg-de Vries equation with a cubic nonlinearity is derived. It is shown that under certain conditions, the effect of electron nonextensivity can be quite important. In particular, it may be noted that due to the net negative dust charge and electron nonextensivity, the present dusty plasma model may admit compressive as well as rarefactive weak DIA-DLS. Considering the wide relevance of nonlinear oscillations in space dusty plasmas, our investigation may be taken as a prerequisite for the understanding of the nonlinear structures observed in the ionosphere and the auroral acceleration regions.     

Dust-ion-acoustic solitary waves and their multi-dimensional instability in a magnetized nonthermal dusty electronegative plasma

A rigorous theoretical investigation has been made on multi-dimensional instability of obliquely propagating electrostatic dust-ion-acoustic (DIA) solitary structures in a magnetized dusty electronegative plasma which consists of Boltzmann electrons, nonthermal negative ions, cold mobile positive ions, and arbitrarily charged stationary dust. The Zakharov-Kuznetsov (ZK) equation is derived by the reductive perturbation method, and its solitary wave solution is analyzed for the study of the DIA solitary structures, which are found to exist in such a dusty plasma. The multi-dimensional instability of these solitary structures is also studied by the small-k (long wave-length plane wave) perturbation expansion technique. The combined effects of the external magnetic field, obliqueness, and nonthermal distribution of negative ions, which are found to significantly modify the basic properties of small but finite-amplitude DIA solitary waves, are examined. The external magnetic field and the propagation directions of both the nonlinear waves and their perturbation modes are found to play a very important role in changing the instability criterion and the growth rate of the unstable DIA solitary waves. The basic features (viz. speed, amplitude, width, instability, etc.) and the underlying physics of the DIA solitary waves, which are relevant to many astrophysical situations (especially, auroral plasma, Saturn’s E-ring and F-ring, Halley’s comet, etc.) and laboratory dusty plasma situations, are briefly discussed.     

Alfvén-Jeans and Magnetosonic Modes in Multispecies Self-Gravitating Dusty Plasmas

Perpendicularly propagating electromagnetic waves in magnetized, multispecies, self-gravitating dusty plasmas are investigated in terms of their wave dispersion properties as well as with respect to their susceptibility to gravitational collapse. In particular, waves on the ordinary as well as extraordinary mode branches are considered. Within the one-dimensional propagation model employed, all modes except the ordinary mode produce density perturbations that can be unstable to gravitational collapse. The wavelengths that are unstable are comparable to the well-known Jeans length for a neutral gas/dust, but there are interesting modifications due to the presence of a magnetic field and charged particles. Furthermore, the effects of the gravitational coupling of a multicomponent plasma to a neutral dust are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Evolution of double layers in magnetised plasmas contaminated with dust charge fluctuations

Coherent structures entailing the existence of double layers have been studied in magnetised plasma contaminated with dust charging fluctuations. It has been shown that the dust charging in magnetic plasma leads to complexity in the derivation of the Sagdeev wave equation, but under way new procedure enable one to study the nature of double layers showing the effective role of the constituents of the plasma. A parametric analysis is a subject of interest in laboratory and space plasmas, and it has been explained with the input of various typical plasma numerics. The proposed mathematical mechanism has shown the success to yield plasma acoustic modes in a dusty plasma which, in turn, has been solved convincingly for double layers. Observations have been evaluated in an appropriate model with a view to agree with the observations in astrophysical problems dealing with present new findings.     

Ion-acoustic instability in a dusty negative ion plasma

The ion-acoustic instability in a dusty negative ion plasma is investigated, focusing on the parameter regime in which the negative ion density is much larger than the electron density. The dynamics of the massive dust grains are neglected, but collisions of electrons and ions with dust grains in addition to other collisional processes are taken into account. The presence of a population of charged dust can change the frequency of the fast wave, lead to additional damping due to ion–dust collisions, and change the conditions for wave growth. Applications to dusty negative ion plasmas in the laboratory and in space are discussed.     

Drift dissipative instability in planetary and cometary dusty plasmas

In a magnetized inhomogeneous dusty plasma drift dissipative instability may play an important role. We have examined the dependence of frequencies and growth rates on dust parameters. The marginal instability for such a dusty plasma seems to show some interesting results. The relevance of the investigation is discussed to understand the wave phenomena in planets and cometary environments.     

Electrostatic solitary structures in a four-component adiabatic dusty plasma

A theoretical investigation has been made of propagating electrostatic waves in a four-component adiabatic dusty plasma, whose constituents are adiabatic electrons, adiabatic ions, adiabatic positively and as well as negatively charged warm dust. The basic features of the solitary structures in such a four-component adiabatic dusty plasma are studied by the reductive perturbation method. It is found that the presence of the positive dust component does not only significantly modify the basic properties of the solitary waves, but also causes the existence of the positive solitary potential structures, which is an interesting feature shown in an adiabatic dusty plasma with the dust of opposite polarity. It is also observed that the basic properties (polarity, speed, amplitude and width) of the DA SWs are significantly modified by the effects of adiabaticity (γ>1) of electrons, ions, negatively as well as positively charged warm dust. The present investigation can be of relevance to the electrostatic solitary structures observed in various dusty space plasma environments (viz. cometary tails, upper mesosphere, Jupiter’s magnetosphere, etc.).     

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.     

Electrostatic shock structures in a multi-species nonthermal dusty plasma

Propagation of the dust-acoustic shock waves (DASWs) in a dusty plasma containing arbitrarily charged dust, positive and negative ions following nonthermal (Cairn’s) distribution, and electrons following q-(nonextensive) distribution, has been investigated. The reductive perturbation technique is used to derive the Burgers equation for dust’s fluid dynamics. The basic features (viz. polarity, amplitude, speed, etc.) of DASWs are found to be significantly modified due to the effects of arbitrarily charged dust, number density and temperatures of heavier/lighter ions, nonextensive electrons, and dust kinematic viscosity. The present investigation can be very effective for understanding the nonlinear characteristics of the DASWs in space and laboratory dusty plasmas.     

Observing the effects of the polarization force in strongly coupled dusty plasmas with suprathermal electrons

Our objective here is to investigate a strongly coupled dusty plasma system with the presence of polarization force (PF). This plasma consists of superthermal electrons, Maxwellian ions, and negatively charged dust grains. The nonlinear propagation of dust-acoustic (DA) waves in such dusty plasma system has been theoretically investigated by employing the reductive perturbation method. The Burgers’ and K-dV equations have been derived to and numerically analyzed. It has been found that the dust-acoustic shock and solitary waves exist associated with a negative potential only, and that the effect of the dust fluid temperature significantly modifies the basic properties (amplitude and width) of such nonlinear waves’ potential structures. We hope that the results of our present investigation should help us in understanding the localized electrostatic disturbances in space and laboratory strongly coupled dusty plasmas with superthermal electrons and polarization force.     

Shock waves in a dusty plasma with dust of opposite polarities

A four-component dusty plasma consisting of electrons, ions, and negative as well as positive dust particles has been considered. The basic features of shock waves that may exist in such a four-component dusty plasma have been theoretically investigated by the reductive perturbation method. The implications of our results in different regions of space (viz. cometary tails, mesosphere, Jupiter’s magnetosphere, etc.) are briefly discussed.     

Characterization of Jovian plasma-embedded dust particles

As the data from space missions and laboratories improve, a research domain combining plasmas and charged dust is gaining in prominence. Our solar system provides many natural laboratories such as planetary rings, comet comae and tails, ejecta clouds around moons and asteroids, and Earth's noctilucent clouds for which to closely study plasma-embedded cosmic dust. One natural laboratory to study electromagnetically controlled cosmic dust has been provided by the Jovian dust streams and the data from the instruments which were on board the Galileo spacecraft. Given the prodigious quantity of dust poured into the Jovian magnetosphere by Io and its volcanoes resulting in the dust streams, the possibility of dusty plasma conditions exist. This paper characterizes the main parameters for those interested in studying dust embedded in a plasma with a focus on the Jupiter environment. I show how to distinguish between dust-in-plasma and dusty-plasma and how the Havnes parameter P can be used to support or negate the possibility of collective behavior of the dusty plasma. The result of applying these tools to the Jovian dust streams reveals mostly dust-in-plasma behavior. In the orbits displaying the highest dust stream fluxes, portions of orbits E4, G7, G8, C21 satisfy the minimum requirements for a dusty plasma. However, the P parameter demonstrates that these mild dusty plasma conditions do not lead to collective behavior of the dust stream particles.     

Waves and Instabilities in Magnetized Dusty Plasmas

The status of waves and instabilities in magnetized dusty plasmas is summarized. The effects of an external magnetic field on low-frequency electrostatic and electromagnetic waves in dusty plasmas are discussed. The kinetic and hydrodynamic instabilities are shown to excite magnetized dusty plasma waves. The presence of the latter can give rise to an oscillatory wake-potential which can be responsible for the charged dust grain attraction. The relevance of our investigation to laboratory and space plasmas has been pointed out. This revised version was published online in July 2006 with corrections to the Cover Date.     

Bifurcations of dust ion acoustic travelling waves in a magnetized quantum dusty plasma

Bifurcation behavior of nonlinear dust ion acoustic travelling waves in a magnetized quantum dusty plasma has been studied. Applying the reductive perturbation technique (RPT), we have derived a Kadomtsev-Petviashili (KP) equation for dust ion acoustic waves (DIAWs) in a magnetized quantum dusty plasma. By using the bifurcation theory of planar dynamical systems to the KP equation, we have proved that our model has solitary wave solutions and periodic travelling wave solutions. We have derived two exact explicit solutions of the above travelling waves depending on different parameters.     

Current-driven dust-acoustic instability in a collisional plasma

The excitation of the dust-acoustic instability in a collisional dusty plasma is investigated. For conditions similar to those of recent laboratory experiments with neutral gas pressures of 100mTorr, it is found that zero-order electric fields E₀ 10 Vm⁻¹ are sufficient for the growth of perturbations with centimeter wavelengths. Much larger wavelengths generally require larger values of E₀. Free electrons in the dusty plasma have a stabilizing effect, which can be very pronounced at the longest wavelengths.     

Solitary waves in a dusty plasma with negatively (positively) charged dust grains and non-thermal electrons

For an unmagnetized multicomponent dusty plasma, the effects of non-thermal electron distribution, ion temperature and two oppositely charged dust grains are incorporated in the study of arbitrary amplitude solitary waves. An energy-like integral equation involving Sagdeev potential is derived, and the existence, formation and basic properties of solitons are studied. It is also found a definite interval for the Mach number for which solitary waves exist and depends sensitively upon the population of fast or non-thermal electrons present. Our results should be useful to understand the properties of localized electrostatic disturbances that may occur in space dusty plasma.     

Some Physical Processes in Dusty Plasmas

Ionized gases containing fine (μm to sub-μm sized) charged dust grains, referred to as dusty plasmas, occur in diverse cosmic and laboratory environments. Dust occurs in many space and astrophysical environments, including planetary rings, comets, the Earth's ionosphere, and interstellar molecular clouds. Dust also occurs in laboratory plasmas, including processing plasmas, and crystallized dusty plasmas. Charged dust can lead to various effects in a plasma. In this review, some physical processes in dusty plasmas are discussed, with an emphasis on applications to dusty plasmas in space. This includes theoretical work on several wave instabilities, the role of dust as an electron source, and Coulomb crystals of positively charged dust. This revised version was published online in July 2006 with corrections to the Cover Date.