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The propagation of small amplitude dust ion acoustic (DIA) solitary waves (SW) in four component relativistic plasma with nonthermal electrons, mobile positively charged ions and positrons, and negatively charged massive dust particles is discussed in this paper. The Korteweg-de-Vries (K-dV) nonlinear wave equation is numerically derived using the reductive perturbation approach. The role of streaming positron beam on the characteristic features of solitary waves are observed and the possible region of the formation of ion acoustic (IA) SW is analysed. The findings of this work will help in the understanding of the Earth's upper atmosphere (Ionosphere's Aurora region) as well as the space plasmas. [ABSTRACT FROM AUTHOR]

We have, present work on kinetic Alfven waves instability in dusty plasma. The expression for the dispersion relation, growth rate and growth length of the kinetic Alfven waves are derived using the particle aspect analysis in auroral acceleration region. Our purpose in this paper is to be investigating the effect of kappa distribution function with dusty plasma on kinetic Alfven waves. The results of the work are consistent for Alfven wave in dusty plasma are applicable of the magnetospheric and astrophysical in auroral acceleration region. [ABSTRACT FROM AUTHOR]

In this paper, the effect of ion-neutral collision type on the ion cloud formation around a dust particle immersed in plasma in the presence of an external electric field is considered. It is shown that elastic ion-neutral collisions in low-temperature low-density plasma lead to the persistence of directed velocity compared to the resonant charge exchange collisions, where ions lose almost their energy. Thus the ion drift velocity is larger for the case of elastic collisions than for resonant charge exchange collisions. With the increase of an external electric field strength, the charge of dust particle increases faster for the elastic case than for resonant case. The dipole moment of the ion cloud-dust particle system is also appeared to have higher values for the case of elastic collisions. [ABSTRACT FROM AUTHOR]

At present, there are several theoretical assumptions that the rotation of the plasma-dust structures in the striation in a magnetic field can be caused by the presence of a number of irregularities. In this paper one of the irregularities, such as the influence of the edge effect at the ends of the solenoids on the rotational motion of plasma-dust structures in the stratum of the glow discharge, was experimentally investigated. [ABSTRACT FROM AUTHOR]

In present paper, the propagation of dust acoustic shocks are investigated in viscous dusty plasma including the effect of polarization force. The considered three fluid model is dealing with electrons, ions and negatively charged dust grains. In the governing model equations, the non-thermal ions distribution, Maxwell Boltzmann electrons and dust polarization force modified by the presence of nonthermal ion population are considered. Using the reductive perturbation method, Burger equation is obtained to study the characteristics of modified dust acoustic shocks analytically and graphically. The viscous and nonthermal polarization force significantly affects the propagation of dust acoustic shocks. [ABSTRACT FROM AUTHOR]

Dust cluster is a stable structure of negatively charged dust particles formed in complex plasmas. This paper briefly describes the dynamics of these objects. Dust clusters are confined by external applied and or self consistent electrostatic plasma fields. Dust cluster may be regarded as energy storage device which stores plasma thermal energy in the electrostatic fields of cluster. This energy is recovered when the cluster explodes upon removal of the confining potential. In this paper a model for the dust cluster explosion in the afterglow phase of a complex plasma discharge is described. The model is tested by MD simulations of dust particles in a confining potential. The nature of the explosion (caused by switching off the discharge) and the concomitant dust acceleration is found to depend critically on the pressure of the back ground neutral gas. At low gas pressure, the explosion is due to unshielded Coulomb repulsion between dust particles and yields maximum acceleration while in the high pressure regime it is due to shielded Yukawa repulsion and yields much feebler acceleration. These results are in agreement with recent experimental findings. The simulations also confirm a recently proposed electrostatic (ES) isothermal scaling relation, PE ∝ Vd-2 (where PE is the ES is pressure of the dust particles and Vd is the confining volume). [ABSTRACT FROM AUTHOR]

In the present paper we derive the plasma dispersion equation under the effect of ionization rate in a dust plasma to investigate the electrostatic ion cyclotron instability, where dust charge fluctuation is absent. It has one of the lowest threshold drift velocities among all the current-driven instabilities in isothermal plasma. The Electrostatic ion cyclotron instability in a dusty plasma containing electrons, light ions, and massive negatively charged dust grains which can be investigated both experimentally and theoretically. [ABSTRACT FROM AUTHOR]

The paper presents a study of the coupling parameter, Γ of ordered structures in the dusty plasma and its dependence on the structural parameter κ. Investigations revealed that this dependence differs in different ranges of κ. If κ < 0.85, a strong interaction of dust grains was observed, whereas it is significantly weaker for κ > 1.4. [ABSTRACT FROM AUTHOR]

The methane decomposition in a planar RF discharge (13.56 MHz) leads both to a dust-particle generation in the plasma bulk and to a coating growth on the electrodes. Growing dust-particles fall onto the grounded electrode when they are too heavy. Thus, at the end of the experiment, the grounded electrode is covered by a coating and by fallen dustparticles. During the dust-particle growth, the negative DC self-bias voltage (VDC) increases because fewer electrons reach the RF electrode, leading to a more resistive plasma and to changes in the plasma chemical composition. In this paper, the cleanliness influence of the RF electrode on the dust-particle growth, on the plasma characteristics and composition is investigated. A cleanliness electrode is an electrode without coating and dust-particles on its surface at the beginning of the experiment. [ABSTRACT FROM AUTHOR]

The paper presents an analysis of the causes of a formation of spatial ordered grain structures in a smoky plasma. We are modeling the process of melting (crystallization) of a condensed phase in this environment taking into account the screened electrostatic interaction and the diffusion-drift force. We discuss an influence of the charge on the melting temperatures. [ABSTRACT FROM AUTHOR]

The role of dust in the space environment is of increasing interest in recent years and also the fast development of fusion devices with a magnetic confinement brought new issues in the plasma-surface interaction. Among other processes, secondary electron emission plays an important role for dust charging in interplanetary space and its importance increases at and above the surfaces of airless bodies like planets, moons, comets or asteroids. A similar situation can be found in many industrial applications where the dust is a final product or an unintentional impurity. The present paper reviews the progress in laboratory investigations of the secondary emission process as well as an evolution of the modeling of the interaction of energetic electrons with dust grains of different materials and sizes. The results of the model are discussed in view of latest laboratory simulations and they are finally applied on the estimation of an interaction of the solar wind and magnetospheric plasmas with the dust attached to or levitating above the lunar surface. [ABSTRACT FROM AUTHOR]

This paper discusses adapting the OML model to estimate the floating potential of dust grains where secondary electron emission is a significant charging mechanism, making it applicable to tungsten dust in tokamaks. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

In this paper, the authors report on a series of experiments that use carefully applied perturbations to a dust cloud to reproducibly investigate the formation of the microparticle cloud and the formation of dust cloud-plasma interface. Here, one micron diameter alumina microparticles are suspended in an argon dc glow discharge plasma. A perturbing voltage pulse is applied to the cathode, causing a momentary disruption in the confinement of the dust cloud. After the perturbation, the cloud reforms, typically with a central “mass” and two “streams” of particles that are flowing into the cloud from both sides. Through the use of stereoscopic particle image velocimetry (stereo-PIV), the complete three-dimensional velocity of the microparticles can be measured. The particles in the streams are used as test particles to characterize the forces acting upon the microparticles. Analysis of the experimental measurements suggests that the effective neutral drag force may be lower than expected. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Primitive meteorites contain rare and tiny grains of presolar stardust with isotopic compositions indicating condensation in the winds or explosions of ancient stars. This paper reviews the isotopic characteristics of the subsets of grains believed to have formed in supernovae or novae and some implications for nuclear astrophysics. [ABSTRACT FROM AUTHOR]

Over the past decade, particle image velocimetry (PIV) techniques have been used to obtain detailed measurements of the thermal and transport properties of weakly-coupled dusty plasmas. This paper reports on the application of an extension of these techniques, tomographic PIV (tom-PIV), which provides an instantaneous volumetric measurement of the particle transport. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to present the most important theoretical and experimental discoveries that have been made in the area of dusty plasma physics. We describe the physics and observations of the well celebrated dust acoustic wave (DAW) and the dust ion-acoustic wave (DIAW) in dusty plasmas with weakly coupled dust grains, as well as the dust Coulomb crystal and dust lattice oscillations (DLOs) in dusty plasmas with strongly coupled dust grains. In dusty plasmas, the dust charge fluctuation is a dynamical variable, which provides a novel collisionless damping of the DA and DIA waves. The latter and the DLOs are excited by external sources, which are here discussed. Besides the Debye-Hückel short-range repulsive force between like charged dust grains, there are novel attractive forces (e.g. due to dipole-dipole dust particle interactions, overlapping Debye spheres, ion focusing and ion wakefields, dipole magnetic moments etc.), which provide unique possibilities for attracting charged dust particles of similar polarity. The dust particle attraction is responsible for the formation of dust Coulomb crystals in laboratory dusty plasmas, as well as for the formation of planets and large astrophysical bodies in the Milky Way galaxy and in interstellar media. Furthermore, the nonlinear DAW, DIAW, and DLOs also appear in the form of solitary and shock waves, the physics and observations of which are briefly discussed. Finally, we discuss possible applications of dust-in-plasmas and dusty plasmas in laboratory and space. [ABSTRACT FROM AUTHOR]

Charged colloidal dispersions and complex plasmas share the classical many-body character of strongly coupled systems but differ in their dynamics, which is overdamped in the colloidal and almost ballistic in the complex plasma case. In this paper, we shall discuss basic properties of charged colloids and emphasize in particular their link to complex plasmas. Similarities and differences between colloids and complex plasmas are discussed. In particular, the charging process in colloidal suspensions, their interactions and the Brownian dynamics is outlined. [ABSTRACT FROM AUTHOR]

The dust acoustic wave (DAW) is a very low frequency (tens of Hz) dust density wave in which the dust particles participate in the wave dynamics. The early experimental observations of DAWs showed that the wave was self-excited by a modest relative ion drift and grew to very high amplitudes (∼100%). In the first part of this paper we describe experiments showing the self-steepening of nonlinear DAWs into dust acoustic shock waves. In the second part we present observations of self-organized, stationary (i.e., non-propagating), stable, dust density structures formed in a DC glow discharge dusty plasma. [ABSTRACT FROM AUTHOR]

The charge on an aggregate immersed in a plasma environment distributes itself over the aggregate's surface; this can be approximated theoretically by assuming a multipole distribution. The dipole-dipole (or higher order) charge interactions between fractal aggregates lead to rotations of the grains as they interact. Other properties of the dust grains also influence the agglomeration process, such as the monomer shape (spherical or ellipsoidal) or the presence of magnetic material. Finally, the plasma and grain properties also determine the morphology of the resultant aggregates. Porous and fluffy aggregates are more strongly coupled to the gas, leading to reduced collisional velocities, and greater collisional cross sections. These factors in turn can determine the growth rate of the aggregates and evolution of the dust cloud. This paper gives an overview of the numerical and experimental methods used to study dust agglomeration at CASPER and highlights some recent results. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations have been extremely successful in the 'first principles' investigation of complex plasmas. Typical examples include studies on phase transition [1], transport [2, 3] and collective behavior [4]. In this paper, we demonstrate the existence of large scale hydrodynamic phenomenology, such as the fundamental Kelvin-Helmholtz instability in sheared flows in 2D Yukawa system by using large scale MD simulations [5] . The system size considered is macroscopic and of experimentally relevant dimensions. Our simulations capture the KH instability, its linear and nonlinear phases, nonlinear saturation leading to turbulence. Existence of inverse cascade, that is, the generation of large scale vortical flows from small scale flows is demonstrated. At the same time, we also show the appearance of dynamic, molecular-level shear heating effects, which heats up the shear layer and thus altering the strong coupling parameter. At the nonlinear stage, while at the smallest scales, the shear heat front expands in the direction perpendicular to the flow, at the largest scale, inverse cascade continues. As our results are first-principles-based particle level description for large system sizes, effects predicted here using MD simulations should be demonstrable in laboratory 2D dusty plasmas. [ABSTRACT FROM AUTHOR]

The crucial point of the paper is the relation between equilibrium distributions of plasma species and the type of propagation or diffusive transition of plasma response to a disturbance. The paper contains a unified treatment of disturbance propagation (transport) in the linearized Vlasov electron-positron and fullerene pair plasmas containing charged dust impurities, based on the space-time convolution integral equations. Electron-positron-dust/ion (e-p-d/i) plasmas are rather widespread in nature. Space-time responses of multi-component linearized Vlasov plasmas on the basis of multiple integral equations are invoked. An initial-value problem for Vlasov-Poisson/Ampère equations is reduced to the one multiple integral equation and the solution is expressed in terms of forcing function and its space-time convolution with the resolvent kernel. The forcing function is responsible for the initial disturbance and the resolvent is responsible for the equilibrium velocity distributions of plasma species. By use of resolvent equations, time-reversibility, space-reflexivity and the other symmetries are revealed. The symmetries carry on physical properties of Vlasov pair plasmas, e.g., conservation laws. Properly choosing equilibrium distributions for dusty pair plasmas, we can reduce the resolvent equation to: (i) the undamped dispersive wave equations, (ii) and diffusive transport equations of oscillations. [ABSTRACT FROM AUTHOR]

In this paper, we studied the effect of strength of dispersion on the formation of solitons and shock waves in un-magnetized dusty plasma using the reductive perturbative technique. Different relational forms of strength parameter [variant_greek_epsilon] were chosen such a way that it altered the stretching of space, x and time, t variables, thereby leading to different nonlinearities. First, we considered the form [formula] and [formula] where v0 is the phase velocity, with 0<[variant_greek_epsilon]<1 is the parameter that measures the strength of the dispersion. We obtained the Korteweg-de Vries (KdV) equation for un-modulated dust acoustic wave with solitary wave-type solution. The effect of dissipation on the wave propagation was analyzed with coordinate transformations ζ = [variant_greek_epsilon](x-v0t) and τ = [variant_greek_epsilon]2t, with 0<[variant_greek_epsilon]<1. This led to Burgers’ equation with shock wave-type solution. From this study, we concluded that when the dissipation effect is negligible in comparison with dispersion, dust charge fluctuations can only change the amplitude of solitary wave, as observed in the KdV case. However, when the system is not sufficiently dispersive, the dissipation due to dust charge fluctuations can play dominant role and eventually leads to the formation of dust-acoustic shock wave. [ABSTRACT FROM AUTHOR]

Three regimes of dust injection are proposed for different applications to fusion energy. In the ‘low-speed’ regime (<5 km/s), basic dust transport study, edge plasma diagnostics, edge-localized-mode (ELM) pacing in magnetic fusion devices can be realized by injecting dust of known properties into today’s fusion experiments. ELM pacing, as an alternative to mini-pellet injection, is a promising scheme to prevent disruptions and type I ELM’s that can cause catastrophic damage to fusion devices. Different schemes are available to inject dust. In the ‘intermediate-speed’ regime (10–200 km/s), possible applications of dust injection include fueling of the next-step fusion devices, core-diagnostics of the next-step fusion devices, and compression of plasma and solid targets to aid fusion energy production. Promising laboratory results of dust moving at 10–50 km/s do exist. Significant advance in this regime may be expected in the near term to achieve higher dust speeds. In the ‘high-speed’ regime (>500 km/s), dust injection can potentially be used to directly produce fusion energy through impact. Ideas on how to achieve these extremely high speeds are mostly on paper. No plan exists today to realize them in laboratory. Some experimental results, including electrostatic, electromagnetic, gas-dragged, plasma-dragged, and laser-ablation-based acceleration, are summarized and compared. Some features and limitations of the different acceleration methods will be discussed. A necessary component of all dust injectors is the dust dropper (also known as dust dispenser). A computer-controlled piezoelectric crystals has been developed to dropped dust in a systematic and reproducible manner. Particle fluxes ranges from a few tens of particles per second up to thousands of particles per second by this simple device. [ABSTRACT FROM AUTHOR]

Dust particle mechanical condition studying is important for question of dust structure stability and phase transitions in complex plasmas, and for ambient plasmas and dust particles parameters diagnostics. The rotation of single dust particles has been observed, followed with the range of theoretical papers, analyzing possible mechanisms, involving particles into rotation. We are observing single dust grains in stratified glow discharge. Rotation is detected with help of direct laser illumination, when the particle surface defects are lighted. Our observations show, that the majority of dust particles has stationary rotation with frequency about hundred Hz. Also it was founded, that there is frequency dependence on the discharge current by linear law. Qualitative interpretation of investigated phenomena is presented. [ABSTRACT FROM AUTHOR]

Streaming dust acoustic instabilities in the presence of a dust beam in a weakly non-ideal dusty plasma have been studied considering a new form for the state equation with two kind of grains. Fluctuating charging effects are not considered in this work. Homogeneous dust-acoustic waves (DAWS) are studied for a perturbed plasma in a very low frequency regime, where dusty plasmas support new kind of waves and instabilities due to the dust collective dynamics. In this analysis a fluid model is used and electrons and ions are determined by their Boltzmann factors in order to find an adequate dispersion relation, which has several parameters depending of the state equation constants. In this paper we use the state equation structured by Ree and Hoover using Padé approximant for a hard-sphere gas in the form P = nT 1 + nb0 1 + a1b0n + a2b02n2/1 - b1b0n + b2b02n2 is applied, where b0 is calculated by the second virial term for the hard-core model. This type of equation is more accurate than other expressions and easier to manipulate. Comparisons between the ideal and non ideal cases is performed. Constants a1, a2, b1, b2, are calculated with the Padé method. The onset of the instability and also the growth rates are studied in function of relevant parameters of the system as the radius of the grains and their densities. In our analysis the instability region for non ideal plasma is compared with that of the ideal ones. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

This paper highlights some of the history of laboratory experiments in dusty plasmas, beginning with an early unexpected discovery of Langmuir. Although there was a great deal of theoretical work on dusty plasmas long before dedicated laboratory experiments were initiated, the experimental work is catching-up and new discoveries in the laboratory are motivating further theoretical work. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Dusty plasma liquid with micro-meter sized fine particles charged and suspended in a low pressure discharge has sub-mm inter-particle spacing for directly monitoring the dynamical behavior of micro-structure and motion. In this paper, we briefly review the generic behavior of structural rearrangement in our dusty plasma liquid experiment. The micro-liquid can be treated as a strongly coupled nonlinear network under stochastic thermal agitation. The cooperative stick-slip hopping is the basic process for structural rearrangement. Under the external persistent shear stress or the topological confinement from boundary, the information are cascaded and eventually randomized in the network through many body interaction and thermal kicks. Structural rearrangement occurs in the form of avalanche type clusters involving a small number of sites. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The paper is devoted to studying the dusty plasma created by the injection of dust particles into the atmospheric pressure gas ionized by an electron beam of 85–120 keV energy. The beam current density was varied within 0.1–1.0 mA/cm2. The electron gun operated in the stationary regime. The behavior of dusty particles lighted by a laser “knife” was observed with a digital video camera. Stable plate-like structures were observed in the cathode sheath of non-self-sustained discharge. Numerical simulation was performed by using the non-local model of the non-self-sustained discharge. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Over the past 5 years, two-dimensional particle image velocimetry techniques have been used to obtain detailed measurements of microparticle transport in dusty plasma. Recently, the Auburn Plasma Sciences Laboratory has extended these techniques to a three-dimensional velocity vector measurement using stereoscopic particle image velocimetry (stereo-PIV). In this paper, we discuss the use of the stereo-PIV technique for determining the velocity space distribution function of the microparticle component of a dc glow discharge dusty plasma. These distribution functions are then used to make measurements of the kinetic temperature of the dust component. Preliminary results show that the temperature of the dust component is significantly larger than the other plasma components (electrons, ions and background neutrals). © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

In this paper has been carried numerical simulation of the interaction of the ion acoustic shocks and one-dimensional dust layers in the argon plasma. Plasmas studied in the frame hydrodynamics model, the charge of dust particles is determined according to the orbit-limited model, the potential of the self-consistent electric field is described by Poisson equation. As a result simulation the spatial distributions of plasma parameters are obtained at different times. It is shown that the velocity of dust ion acoustic shocks is increased at the front boundary, and one is decreased at the back boundary of the dust cloud. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

A study has been made of the distributions of electric and velocity potentials around a dust particle immersed in a flowing, collisionless plasma. The dust particle acts as a sink for both ions and electrons, since it can draw no net current in the steady state. The dust particle is also assumed to be small compared with the Debye distance. An earlier paper considered the flow around an object much larger than the Debye distance. In the present case an analytical solution has been found for both the electric potential and the velocity potential in cases where the ion streaming is slow. The electric potential contains a strong dipole component and a lesser contribution due to the small space charge associated with a quasi-neutral region. Further modelling and numerical work is required to obtain the solution to the problem for high ion streaming velocities. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

In the present research paper, characteristics of dust-acoustic solitary waves in dusty plasma are studied. The dust charge is treated as variable. KdV equation has been derived using reductive perturbation method. The effect of relative number density, relative ion temperature, non-thermal parameter and variable charge has been numerically studied for possibility of both type of dust-acoustic solitary waves. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Dust particles in a radio-frequency discharge generally obtain a negative charge due to the high mobility of the electrons compared to that of the positive ions. When a sufficiently intense flux of photons in the UV range is present, however, the dust charge will be less negative due to photodetachment. The resulting charge distribution will depend on the competition between collection of electrons and ions from the plasma and the detachment by photons. In this paper we study the influence of photodetachment on the charge of dustparticles suspended in a radio-frequency discharge, as well as its influence on the electron energy distribution function and the electron and ion density profiles. An existing Particle-In-Cell code has been modified to include the photodetachment process. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

When dust particles are created in a radio-frequency processing discharge or when they are introduced from outside, they obtain a negative charge due to the large mobility of the electrons. A high dust density therefore changes the discharge characteristics, not only by the presence of an almost immobile charge, but also because there is a continuous loss of ions and electrons by recombination at the surface of the dust particles. In this paper we use a 1D Particle-In-Cell plus Monte Carlo model to investigate the interaction between the electron energy distribution and the dust charging plus recombination process, its influence on the plasma impedance and on the ionization rate. The background gas is argon and a spatial distribution of immobile mono-disperse spherical dust particles is prescribed. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

During the last decade, we have seen a very rapid growth of the dusty plasma physics with many discoveries. The latter include the dust acoustic wave, the wakefield and the ion focusing (which are responsible for the attraction of charged dust grains), the dusty plasma crystals as well as coherent nonlinear structures comprising the dust ion-acoustic shocks, the dust acoustic Mach cones, voids, and vortices. Since the dusty plasma physics involves the charging and the dynamics of extremely massive charged dust grains, it can be characterized as a complex plasma system whose characteristics are significantly different from the usual multi-ion plasmas. In this paper, we present the properties of a complex dusty plasma, as well as discuss two novel instabilities that are responsible for the excitation of low-frequency electrostatic modes in an unmagnetized dusty plasmas. The instabilities are associated with the combined effects of a dc electric field and the dust charge gradient on one hand, and the rotation of elongated dust grains on the other hand. The implications of the present investigation to laboratory and space plasmas are discussed. [ABSTRACT FROM AUTHOR]

In this paper the foundation is layed for the nonmodal investigation of velocity shear induced phenomena in a differentially rotating flow of a dusty plasma. The simplest case of nonmagnetized flow is considered. It is shown that, together with the innate properties of the dusty plasma, the presence of differential rotation, Coriolis forces, and self-gravity casts a considerable richness on the nonmodal dynamics of linear perturbations in the flow. In particular: (i) dust-acoustic waves acquire the ability to extract energy from the mean flow and (ii) shear-induced, nonperiodic modes of collective plasma behaviour — shear-dust-acoustic vortices — are generated. The presence of self-gravity and the nonzero Coriolis parameter (“epicyclic shaking”) makes these collective modes transiently unstable. [ABSTRACT FROM AUTHOR]

This paper deals with mode in non rotating horizontally stratified dusty atmosphere. We have studied dust gravity and acoustic modes in presence of a barometric equilibrium in an unmagnetized dusty plasma. All the dust grains are considered to have same and fixed negative (positive) charge on them. The electron and ions are considered to obey isothermal equations of state while the dust grain are following an adiabatic equation of state. This work can be considered as a generalization of single fluid treatment of gravity-acoustic modes. The analysis of dispersion relation suggests that the dust grains can introduce a new decay length of the perturbation. Therefore we find that the dispersion characteristics of single fluid treatment is strongly modified in the presence of charged dust grain. Finally we discussed importance of our results in the context of planetary and stellar environments. [ABSTRACT FROM AUTHOR]

It has been shown that rotation has to play a predominant important role in the formation of many astrophysical objects and the stability of molecular clouds. In this paper the theoretical investigation of the presence of rotation in the magnetized dusty plasma. The general dispersion relation is obtained normal mode analysis technique, and we found the Alfven mode is modified due to the presence of rotation and magnetic field. The graphical presentation shows that rotation and Alfven wave velocity have a stabilizing in the system. [ABSTRACT FROM AUTHOR]

The formation of elongated dust particles in a spherical dc glow discharge in ethanol was observed for the first time. Dust particles were formed in the process of coagulation of ethanol dissociation products in the plasma of gas discharge. During the process the particles were captured into clouds in the electric potential wells of strong striations of spherical discharge. The size and the shape of dust particles are easily detected by naked eye after the illumination of the laser sheet. The description of the experimental setup and conditions, the analysis of size, shape and composition of the particles, the explanation of spatial ordering and orientation of these particles are presented. [ABSTRACT FROM AUTHOR]

The propagation of nonlinear dust ion acoustic (DIA) solitary wave (SW) in dusty plasma consisting of positive and negative ions, nonthermally distributed electrons and positrons is studied in presence of magnetic field effect. The three-dimensional Zakarov-Kuznetsov (Z-K) equation is derived, using reductive perturbation technique and the solution is obtained using tan-hyperbolic method. It is observed that the bifurcation point (the point where two streams of nonlinear waves split) for compressive and rarefactive solitary waves are found to be on opposite sides of each other. Also, it is seen that at a certain value of nonthermal electrons in plasma, the transition from compressive to rarefactive solitary wave is observed. [ABSTRACT FROM AUTHOR]

Dust charging effects to analyze the ion-beam plasma system is of vital importance due to the fact that the dust particles could accept very high charge states. In this paper we propose a suitable dispersion relation for a one dimensional dust ion-beam plasma system to calculate the growing rates and phase velocities of ion acoustic waves propagating in the system. We use an hybrid model to describe electrons as a fluid while ions are described by kinetic theory. The charge state of dust particles has a strong effect on the threshold on beam velocity of the onset of the instability. We apply also an algebraic method described in previous works to simplify the calculations. [ABSTRACT FROM AUTHOR]

The motion of dust particles in the potential of the form v = -ar+br2 has been discussed. This form of potential comes from the combination electrostatic (Fes = cr3) and shadowing (Fshadow = -dr2) forces affecting to two negatively charged dust particulates. The electrostatic force between them is repulsive, while the shadowing force is attractive. In this paper we will show that the dynamics and motions of dust particles vary with plasma parameters and also we can investigate the dynamics and motions of dust grains in three negatively charged dust particles via theory and modelling. The possible motions of dusts particulates are studied and discussed through the equipotential curves obtained via simulation. [ABSTRACT FROM AUTHOR]

In this paper the recent experimental achievements in a research field of a dusty plasma structures forming including elongated structures, and changes of their structural and kinetic characteristics in a glow discharge plasma [1, 2] with various gas and dusty filling are presented. [ABSTRACT FROM AUTHOR]

This paper reports the modelling of CCP-RF discharges (13.56 MHz) in pure nitrogen, produced within a cylindrical parallel-plate reactor, similar to a GEC reference cell surrounded by a lateral grounded grid, at 0.1–2 mbar pressures and 10–50 W coupled powers. This study is a first step in simulating Titan’s chemistry at laboratory scale, using the PAMPRE experiment. Modelling results are compared with experimental measurements of the average electron density, and the self-bias potential at the polarized electrode. [ABSTRACT FROM AUTHOR]

In order to solve the problem of the Brownian motion of one particle under the effect of a friction-like external force, we have followed two different approaches to calculate the transition probability and by consequence be able to compute the probabilities for this stochastic process. The first approach is statistical based on Smoluchowski stochastic equation and we used the Gaussian modeling technique to solve it, while the second is a path integral approach based on Langevin semi-dynamical equation and Wiener path integral techniques. The transition probability expressions obtained by those two approaches are not similar, but it is found that they converge to each other to the point that they becomes identical numerically under a certain condition, this condition turned to be a physical constraint which is due to the difference on the time variation scales between the stochastic microscopic force and the friction-like macroscopic force. At the end a model for dusty plasmas is proposed as a practical direct application of our theoretical results. [ABSTRACT FROM AUTHOR]

Two distinct scenarios have been proposed to explain the origin of dust observed in the high-redshift (z = 6.4) quasar J1148+5251. The first scenario suggests that because of the relatively young age of the universe (∼890 Myr), only massive stars could have produced the large amount of dust observed in this object. The second scenario assumes a significantly older galactic age, so that most of the dust could have formed in lower-mass AGB stars that would have sufficient time to evolve off the main sequence. In this contribution we offer a critical analysis of both scenarios, and briefly discuss alternative suggestions for the origin of dust in this object. [ABSTRACT FROM AUTHOR]

We summarize cm through submm observations of the host galaxies of z∼6 quasars. These observations reveal cool molecular gas (the fuel for star formation), warm dust (heated by star formation), fine structure line emission (tracing the CNM and PDRs), and radio synchrotron emission. Our results imply active star formation in ∼30% of the host galaxies, with star formation rates ∼103 M⊙ year-1, and molecular gas masses ∼1010 M⊙. Imaging of the [CII] emission from the most distant quasar reveals a 'maximal starburst disk' on a scale ∼1.5 kpc. Gas dynamical studies suggest a departure of these galaxies from the low-z MBH-Mbulge relation, with the black hole being roughly 15 times more massive than expected. Overall, we are witnessing the coeval formation of massive galaxies and supermassive black holes within 1 Gyr of the Big Bang. [ABSTRACT FROM AUTHOR]

A historical overview of some of the early theoretical and experimental work on dust acoustic waves is given. The basic physics of the dust acoustic wave and some of the theoretical refinements that have been made, including the effects of collisions, plasma absorption, dust charge fluctuations, particle drifts and strong coupling effects are discussed. Some recent experimental findings and outstanding problems are also presented. [ABSTRACT FROM AUTHOR]

This is a short overview of recent results demonstrating the importance of ion-neutral collisions for different processes naturally occurring in complex (dusty) plasmas. Most important developments are briefly discussed and relevant references are provided. [ABSTRACT FROM AUTHOR]