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Melamine formaldehyde microspheres are widely used in dusty plasma experiments for their monodispersity, sphericity, low mass density, and well defined sizes. This paper summarizes problems that were encountered in numerous applications of these grains in different laboratory simulations. and the already published results are discussed in view of new experiments. The main results of this paper are connected with changes of the grain mass due to the decreased pressure and/or increased temperature and variations of the grain dimensions, its shape, and mass density under electron or ion bombardments. By contrast to the work function estimated from field emission properties, we have found the photoelectric work function (4.5 eV) being close to that expected. A sputtering of the grains using a 30-keV ion beam revealed their unexpected heterogeneity. [ABSTRACT FROM AUTHOR]

Applicability limit of the well-known phase diagram of dusty plasmas in κ-Γ plane (κ is structural parameter and κ is parameter of Coulomb nonideality) is under discussion. Existence of extensive domains with violation of plasma thermodynamic stability conditions (i.e., with negative isothermal compressibility) was also claimed if one uses well-known nonideal equations of state by (Hamaguchi S. et al., Phys. Rev. E, 1997) and (Khrapak S. et al., Phys. Rev. E, 2014). This paper is devoted to analysis of a range of applicability for basic assumption in Hamaguchi's phase diagram, i.e., linearized (Debye) screening of macroions by microions, which leads to the Yukawa form for effective interactions between macroions. Parameters of nonlinear screening for macroions were calculated within differential Poisson--Boltzmann equation. Two effects were revealed as a result of such calculations: 1) decomposition of all microions onto two subclasses, free and bound ones, and 2) significant reduction of effective charge Z* of initial bare macroion Z under nonlinear screening by small high-density envelope of bound ions. This effect leads to a renormalization of initial Γ and κ into Γ* and κ* (Γ* < Γ, κ* < κ). The main physical assumption is phase states of complex plasma under nonlinear screening, which are still the same as on the initial phase diagram, but in κ*-Γ* plane instead of κ-Γ one. Corresponding calculated shifts of phase states are discussed and illustrated. [ABSTRACT FROM AUTHOR]

This paper presents the results of a recent study of the interaction between charged dust particles and plasma ions through the electrostatic and ion drag forces in a dc glow discharge plasma. Measurements of the dust particles motion are carried out using particle image velocimetry (PIV). When an electrostatic perturbation is applied to the dust cloud, the particle motion, in response to the perturbation, is shown to reverse direction as the gas pressure is increased. An analysis of the dust particle motion and background plasma parameters suggests that there is a change in the equilibrium position and competition between the electrostatic force and the ion drag force on the particles that lead to the asymmetric motion of the cloud. The ion drag and electric forces on the dust particles are calculated at each pressure using detailed measurements of the plasma parameters, as measured by a single Langmuir probe. The analysis of these measurements suggests that the reversal of direction is a result of the change in the electric field in the plasma, but that the effectiveness of the perturbation at displacing the dust cloud is controlled by the ion drag force. [ABSTRACT FROM PUBLISHER]

Dispersion is one of the important characteristics of dusty plasma. In this paper, the real and imaginary parts of the complex refractive index of dusty plasma are first deduced and verified by the Kramers–Kronig dispersion relation. And then, the dependence of dispersion ability on the temperature, pressure, angular frequency of incident electromagnetic wave, as well as the number density, radius, and charge of dust particles is given. Finally, the theoretical results indicate that: 1) the dispersion ability decreases with the increase of angular frequency; 2) the dispersion ability monotonically varies with the pressure approximately, but nonmonotonically varies with the temperature; and 3) the dispersion ability monotonically increases with the increase of dust particle’s charge, but nonmonotonically changes with the number density and radius of dust particles. In particular, the involved physical explanations are proposed. [ABSTRACT FROM AUTHOR]

This paper reports the levitation of micro-organisms in the sheath of radio-frequency (RF) plasma. Based on simple force-balance calculations, the required electric field for the levitation of micro-organisms has been estimated. It is predicted that micro-organisms could levitate at the periphery of the sheath. Experimental results demonstrate the levitation of two species of bacillus micro-organisms Escherichia coli (E. coli) and Klebsiella pneumoniae in an RF plasma. The almost monodiverse Klebsiella pneumoniae levitating in the RF plasma formed an ordered state similar to a 2-D Coulomb crystal. Diverse E. coli particles demonstrate the tendency that the levitating height of micro-organisms decreases as the radius of particles increases. Levitating micro-organisms in plasmas can be referred as dusty plasmas. [ABSTRACT FROM AUTHOR]

In dusty plasmas, dust particles are levitated by balance of forces inward to the plasmas (typically corresponding to electrostatic force) and outward from the plasmas (ion drag force) as well as gravity. The balance of the forces tends to make a region free from dust particles, so-called void at the center of the plasmas. This paper made it clear in measurements of ion density and electron temperature with a double-probe method that the void was a region involving ionization. The dust particles were distributed in the other region diffusion dominant for electrons and ions. The void is shown to be reduced by restricting the region involving ionization. [ABSTRACT FROM AUTHOR]

This special Issue focuses on the field of dusty plasmas or also referred to as complex plasmas. Most of the papers were presented at the 8th International Conference on the Physics of Dusty Plasmas (8 ICPDP, ), which was hosted by Charles University and held in Prague, Czech Republic, on May 20–25, 2017. We would like to join the continuous tradition of special issues of the IEEE Transactions on Plasma Science from April 1994, 2001, 2004, 2007, 2010, 2013, and 2016 associated with the other most important triennial meeting for the community, the Workshop on the Physics of Dusty Plasmas. We believe that these two conferences and papers connected to them reflect the current state of the art and progress in the field. [ABSTRACT FROM AUTHOR]

This paper presents the results of experimental and numerical investigation of the influence of dust nanoparticles on glow discharge plasma properties. A special apparatus was developed to provide a steady input of dust nanoparticles into ac glow discharge plasma. The plasma was created in a large-volume coaxial gridded hollow cathode. A novel simulation approach of dusty plasma was developed specifically for the experimental conditions. An extended fluid approach with drift-diffusion approximation for the electron and ion fluxes was modified to account for charged dust nanoparticles’ contribution to net charge and for ion and electron loss on the surface of particles. Uniform distribution of dust particles in plasma and instantaneous charging process were assumed during simulations. Experimental measurements were carried out using Langmuir probe. Simulations and probe measurements were carried out before and after input of dust particles into plasma. Under the conditions studied both methods showed a decrease by a factor of 5 in electron density caused by input of dust nanoparticles. [ABSTRACT FROM AUTHOR]

Linear and nonlinear properties of obliquely propagating waves are studied in a degenerate dense cold magnetoplasma, comprising of Thomas–Fermi distributed electrons and ions as well as non-degenerate negatively charged dust particulates. By using the plane wave approximation, a linear dispersion relation for the dust-cyclotron (DC) and dust-acoustic (DA) waves is derived and analyzed numerically. For fully nonlinear waves, a Sagdeev pseudopotential theory is employed to derive an energy-balance equation and the soliton existence domain depending upon the dust concentration $(h)$ , obliqueness $(L_{z})$ , and Mach number $(M)$. Numerical analysis reveals that the parameter $h$ enhances the domain for allowed Mach numbers, i.e., $M_{1} < M < M_{2}$ and therefore favoring the solitary excitations, where $M_{1}$ and $M_{2}$ are the lower and upper Mach numbers, respectively. In addition, the dust concentration significantly reduces the amplitude and the profile sharpness of the solitary pulses. Similarly, variations in the obliqueness parameter and the Mach numbers modify the wave characteristics. This paper is important for understanding the nonlinear properties of electrostatic excitations in degenerate dusty magnetoplasma, relevant to white dwarfs (WDs), namely $GD56,\,\,GD29-38,\,\,GD362$ , and $WD2115-560$ , being termed as the DUSTY DAZ WDs. [ABSTRACT FROM AUTHOR]

In this paper, we present the results of experimental investigation of the properties of dusty plasma formed in a pulsed plasma accelerator (IPU-30) through the interaction of pulsed plasma beams with a carbon-based target. In the experiments, the interaction of beams of the pulsed plasma with the surface of the carbon plates affords instantaneous heating of the target substrate and subsequent ejection of dust particles from the surface of the plates into the plasma bulk. These dust particles are dragged by the plasma beam creating a moving plasma-dust cloud. A high-speed camera (Phantom VEO710S) is used to obtain the velocity of the dust particles in a beam of the pulsed plasma. Ejection of dust particles is investigated at two different values of the discharge voltage (7 and 12 kV). [ABSTRACT FROM AUTHOR]

Over the past 25 years, the dust acoustic wave has been a subject of intense study and the impact that thermal effects have on the dispersion relation has been a subject of investigation. Recently, a theory of dust correlations and the effect that these correlations have on the propagation of compressional modes has been developed that incorporates the effects of the confinement of the dust cloud in a finite volume within the larger plasma volume. This paper applies this model to a systemic study of the dispersion relation over a wide range of experimental conditions in a radio frequency (RF) discharge plasma. It is found the dust thermal pressure is larger than the dust electrostatic pressure and that both pressures are the square of the dust charge calculated using the orbit-motion-limited (OML) theory. It is also observed that the dust temperature and thermal pressure decreases with increasing neutral gas pressure. [ABSTRACT FROM AUTHOR]

Modeling the dynamics of charged dust particles, confined in a glass box placed on the lower electrode of a Gaseous Electronics Conference cell, requires that the interactions between the charged dust, plasma, and boundaries need to be accounted for in a self-consistent manner. The charged lower electrode affects the plasma conditions throughout the glass box, altering the electron and ion densities and temperatures within the plasma sheath. These plasma characteristics determine the charge collected on the walls of the surrounding glass box, the electric potential within the glass box, the dust charge, and ultimately the dynamics of the dust. This paper describes the steps taken to build a simple model of the relationship between the plasma conditions and the potential within the box as well as the expected dust charge near the center of the box. The calculated potential and dust charge are used to construct acceleration maps for the dust, which are compared to experimentally measured acceleration of the dust within the box. [ABSTRACT FROM AUTHOR]

In complex plasma, asymmetric ion flow toward the sheath gives rise to a well-known attractive oscillatory wake potential. In this paper, an investigation of effect of ion flow-induced wake potential on thermal conductivity and shear viscosity in strongly coupled complex plasmas has been reported for the first time. Green–Kubo formalism along with Langevin dynamics simulation has been used to estimate the thermal conductivity and the shear viscosity of strongly coupled dust fluid in the presence of external magnetic field and attractive wake potential superimposed with repulsive Debye–Hückel potential for a wide range of the Coulomb coupling parameter ($\Gamma $), the screening parameter ($\kappa $), the neutral pressure ($n_{\mathrm{ n}}$), and the magnetic field $B$. [ABSTRACT FROM AUTHOR]

This paper presents an analysis of the application of the time-resolved Hilbert transform to simulated measurements of the wave structure in the dust acoustic wave. It is shown that the observation of structures in the dominant frequency modes that have been made in experimental measurements of the driven dust acoustic wave is due to the nonlinearity in the wave mode and that the time-resolved Hilbert transform can be used to measure the nonlinearity in the driven wave mode. This was tested on experimental data and excellent agreement was observed. [ABSTRACT FROM PUBLISHER]

In this paper, the influence of the additional impact of electrostatic field on dusty and buffer plasma parameters is investigated. It is shown that the addition of a light gas to heavy one and the additional impact of a constant field on the radio frequency discharge lead to changes in the spatial characteristics of the buffer plasma and the location of the plasma-dust structure in the interelectrode space. [ABSTRACT FROM PUBLISHER]

This paper discusses the design of the new Magnetized Dusty Plasma eXperiment (MDPX) device that is currently under construction at Auburn University. This device, which is envisioned to be operated as a multiuser facility, has incorporated many of the features of current dusty plasma experiments that make use of strong magnetic fields while adding new features—such as an extended plasma volume, programmable linear magnetic field gradients, and variable magnetic field geometries—that will greatly extend the operating space of the new device. This paper discusses the physics criteria used to define the operating parameters of the MDPX device and presents a discussion of the initial configuration of the experiment. [ABSTRACT FROM PUBLISHER]

The quantum hydrodynamic model is considered to investigate the Jeans instability of three species ultracold inhomogeneous dusty plasma. The formulation of this paper is based on the assumption that the electron and ion inertial force is negligible in comparison with the electron and ion pressure and force associated with the electron and ion correlations at the quantum scale. The gravitational force acting on the negatively charged dust grains is considered in the presence of both the electrostatic and polarization forces taking into account the quantum diffraction and statistical contributions of dust particles. The modified dispersion relation is derived and analyzed to obtain the instability criterion by including the dust polarization force and the quantum corrections. Numerical results are presented to show the effect of these modifications on the growth rate of Jeans instability. The present investigation is relevant to the collapse of ultracold astrophysical objects like the inner core of white dwarf and neutron star. [ABSTRACT FROM PUBLISHER]

We made use of a combination of three models that describe plasma equilibrium, cluster kinetics, and aerosol dynamics in order to investigate solid carbonaceous dust formation in a dc gas discharge where the carbon source is provided by a graphite cathode sputtering. This enabled us to determine the time evolution of some of the particle characteristics, e.g., total density, mean diameter, and average charge, as a function of the sputtering yield. We showed that for a few minutes of discharge duration, the particle density reaches 10^7 – 10^8 cm ^-3 , the particle mean diameter is approximately 40 nm and the particle size distributions are bimodal for all the investigated conditions. We also showed that the variation of the sputtering yield affects in a quite unexpected way the interplay between the phenomena involved in the aerosol dynamics. Basically, larger sputtering yields result in larger density and coagulation rate on one hand, and in a limited nucleation and surface sticking kinetics on the other hand. [ABSTRACT FROM PUBLISHER]

In this paper, the effect of the magnetic field on dust dynamic and lifetime in the edge fusion plasma has been studied. A computational model of tungsten dust evolution formed on the surface of the reactor wall was constructed on the basis of particle-in-cell and Monte Carlo methods. The time dependence of the characteristic parameters (charge, temperature and radius, and heat fluxes) of the dust particle was determined. On the basis of these calculations, estimates of the tungsten dust lifetime in the edge fusion plasma were made. It was found that the magnetic field can have a significant effect on charging processes and lifetime of dust particles in the edge fusion plasma. The obtained results show that the larger the dust particle size, the stronger the magnetic field affects its charge, which leads to the suppression of the heat flux of plasma particles on the dust surface and an increase in its lifetime. Also, the magnetic field increases the charging time of small dust particles due to the limitation of the trajectory along the magnetic field lines. [ABSTRACT FROM AUTHOR]

Incandescent dust particles are observed to the naked eye in pure acetylene plasmas excited at electron cyclotron resonance (ECR). Their transport in a plane parallel to the magnets is studied using fast imaging combined with a tracking algorithm. The dynamics of dust particles exhibit specific trends depending on the direction considered within the magnetic field ($\vec {B}$), the position in the plasma reactor, and the time after plasma ignition. This transport is discussed considering the electric and the ion drag forces. Although the transport of dust particles is governed by the space-charge electric field in the direction parallel to $\vec {B}$ , it involves cross-field mechanisms in the direction perpendicular to $\vec {B}$ related, specifically, to the ambipolar $\boldsymbol { }\vec {E}\boldsymbol {\times }\vec {B}$ drift as supported by a simple model. However, to fully describe these transport phenomena, one would also consider spatial and time-evolutions of plasma parameters in the dusty plasma. [ABSTRACT FROM AUTHOR]

The effect of an external magnetic field on the dust particle charging in gas discharge plasmas has been studied using the particle-in-cell and Monte Carlo methods at 1, 2, and 4 T. This paper presents the results for the dust particle charge and the characteristic dust particle charging time for different values of the magnetic field induction. Our simulations have shown that the external magnetic field reduces the absolute value of the dust particle charge and extends the characteristic charging time. In addition, the number density of electrons and ions decreases in the vicinity of the dust particle due to the magnetic force, which we interpret as the action of the external magnetic field hampering plasma flow to the surface of the charged dust particle. To visualize this effect, we show the trajectories of the electrons and ions around the dust particle at different values of the magnetic field induction. [ABSTRACT FROM AUTHOR]

Dust kinetic temperature is a measure of the energy of the stochastic motion of a dust particle and is a result of the combination of the Brownian motion and the fluctuations in the dust charge and confining electric field. A method using the equilibrium value of the mean square displacement was recently introduced to obtain the dust kinetic temperature experimentally. As a follow up, this paper investigates the relationship between the dust kinetic energy derived from the mean square displacement technique and a technique using the probability distribution of the displacements obtained from random fluctuations of the dust particle. The experimental results indicate that the harmonic confinement potential acting on the dust particle can be obtained by combining the two methods, allowing the nonlinear effect of the confining force to be investigated. The thermal expansion in a 1-D vertical chain is discussed as a representative application as it is related to the nonlinear confinement force, or the asymmetric confinement potential. [ABSTRACT FROM AUTHOR]

An experimental method of producing dusty plasma with high dusty particle density is proposed and implemented. Microdusty particles are immersed into an ac glow discharge plasma with large scale by applying electronically controlled vibratory screen mesh and continuous equidistributional dusty environment is formed. The impact of dusty particles on microwave propagation in a laboratory plasma device can be observed. The gigahertz microwave transmittance through the dusty plasma region is measured with vector network analyzer and horn antenna placed in the sides of plasma region. The results show that the dusty particles can synergize the influence on propagation of microwave in plasma. [ABSTRACT FROM AUTHOR]

Arcs between carbon electrodes present some specific differences compared with metallic arcs. The arc voltage is higher, but does not attain a stable value displaying large fluctuations. Indeed, the arcs are produced by the direct sublimation of the electrodes, without passing through a molten phase. The arc production is also facilitated by both circuit breaking and electric field breakdown. In this paper, arcing has been examined under various conditions (voltage, current, and opening or fixed interelectrode gap) and particular attention has been given to the ability of the system to sustain the arc due to reignition. Small-angle X-ray scattering has been used to examine the formation of particles within carbon arcs and again the results are different from what is found with metallic electrodes, the particles being larger with rougher surfaces. The ultimate aim of this paper was to gain new knowledge concerning these arcs and their consequences for electrical safety (arc faults in wires). [ABSTRACT FROM PUBLISHER]

Editorial. Introduces the articles featured in the April 2001 issue of the `IEEE Transactions on Plasma Science,' which deal with dusty plasmas. Background on dusty plasmas; Categories of the papers dealing with dusty plasmas; Dedication of the issue to physicist D. Asoka Mendis.

The Einstein frequency $\Omega _{E}$ was experimentally determined for a 2-D dusty plasma. We found $\Omega _{E}= 49.4 ~\text{s}^{-1}$ and 50.2 s−1 for the collection of microspheres in a crystalline and liquid-like state, respectively. Comparing to the nominal 2-D dust plasma frequency $\omega _{\mathrm {pd}}$ , we found the ratio $\Omega _{ E}$ / $\omega _{\mathrm {pd}}\approx 1$ / $\surd 3$. This experimental ratio is consistent with previous predictions of Yukawa simulations. Our results were obtained by analyzing images of the microspheres to obtain their positions, charge, and the screening length; we used these measurements to calculate resonant frequencies of test particles. [ABSTRACT FROM AUTHOR]

Investigation of linear dust-acoustic (DA) waves was analyzed in a system of collisionless, dissipative, and unmagnetized four-component dusty plasma consisting of cold positively and negatively charged particles of dust, with ions and electrons are of the Boltzmann distribution. The compatibility condition is obtained by using the normal mode analysis. The Korteweg de Vries–Burgers (KdV–Burgers) equation is obtained when the plasma system is nonlinearly analyzed by the reductive perturbation method. To study the nonlinear waves, we obtain some interesting physical solutions. These solutions are in the form of soliton, a combination between a shock and a soliton, and finally monotonic and oscillatory shock waves. Graphical illustration for these solutions was presented. The characteristics of the DA solitary and shock waves are significantly modified by the presence of positive and negative dust ions, the ratio of the ion to electron temperatures, and it is also found that the basic features are affected by the dust kinematic viscosity. The planar dynamical systems bifurcation theory, which was used to establish the existence of solitary wave solutions and periodic traveling wave solutions, has been established. Accordingly, the phase portrait topology and the potential diagram are illustrated for the KdV–Burgers equation. As a result of different phase orbits, there is an advantage to predict different classes of traveling wave solutions. The electric field is determined. Generalization of the obtained results in this paper can be used to investigate the nature of plasma waves in both laboratory and space. [ABSTRACT FROM AUTHOR]

In this paper, a reductive perturbation theory is used to derive a Korteweg–de Vries equation for a magnetized dusty plasma consisting of cold dust grains, Boltzmann distributed electrons, and Boltzmann distributed ions at two different temperatures. The renormalization method is used to obtain stationary solutions of these coupled equations. The effects of two-temperature ions and external magnetic field on the properties of solitary waves are studied. Such a study showed that the presence of the hot and cold ions modifies the nature of dust-acoustic solitary structures and admits mainly solitary waves with negative potential. However, for a small amount of electron density, the plasma may allow rarefactive dust-acoustic solitary waves to exist in such a dusty plasma system. [ABSTRACT FROM PUBLISHER]

Over the past twenty years, the dust-acoustic wave (DAW) has been a subject of intense study. In this paper, high-speed video imaging is employed to measure the evolution of wavefronts of a propagating DAW as it propagates through a weakly coupled dusty plasma system in an argon dc glow discharge plasma. In particular, measurements of the growth, saturation, and, then, damping of the wave mode as the wave propagates through the cloud are reported. It is observed that the wave amplitude initially exhibits rapid growth while the wavefront compresses. After this initial growth, the width of the wavefront remains relatively constant, while the amplitude of the wavefront evolves like the background dust medium. In some cases, it is also observed that the wave amplitude can decay more quickly than the background dust medium. [ABSTRACT FROM PUBLISHER]

Molecular dynamic simulations were performed to study the characteristics of particle flows in a toroidal trap driven by the ion drag under the influence of gravity, interparticle forces, and friction with a neutral gas background. This paper is focused on the influence of the driving force and the strength of friction on the dynamics of the dust flow and its different regimes. For small values of the ion drag, the particle flow exhibits instabilities with strong velocity fluctuations, while for high values of the ion drag, a quiescent particle flow is obtained. The transition from unstable flows to quiescent flows is studied in detail. [ABSTRACT FROM PUBLISHER]

In the circuits of high-power microwave (HPM) devices, such as HPM sources and/or high-gradient accelerating structures, small quantities of metallic dust may exist. These metallic particles of a micrometer size being located in the region of high RF magnetic field can absorb enough energy for significant heating and even melting. The melted clumps can then impinge on structure surface and create nonuniformities, leading to the RF field enhancement and subsequent breakdown events. This heating process in single long-enough RF pulses was analyzed in our previous paper (“Possible role of RF melted microparticles on the operation of high-gradient accelerating structures,” Phys. Rev. ST—Accel. and Beams, 12, 101001, 2009). In this paper, we consider similar processes in HPM devices operating in repetition-rate regimes. The process of particles cooling between RF pulses is first analyzed under an assumption of blackbody radiation. Then, the applicability of this assumption is discussed, and the effect of deviation from it is estimated. It is shown that the melting of metallic particle of a size comparable to the skin depth in HPM devices is possible when the RF magnetic field, microwave pulse duration, and repetition frequency are large enough. [ABSTRACT FROM AUTHOR]

Over the past 15 years, the dust acoustic wave has been a subject of intense study, and, in recent years, thermal effects in the dust acoustic wave have emerged as a new area of investigation. This paper presents preliminary measurements of the kinetic dust temperature using the dispersion relation of this wave mode as a function of the neutral gas pressure. It is found that dust temperature is significantly larger than the other plasma components and decreases with increasing neutral gas pressure. [ABSTRACT FROM AUTHOR]

This paper presents the result of a new evaluation of particle image velocimetry (PIV) as applied to dusty plasmas. In this work, the PIV analysis technique is used to analyze the velocity distributions of particles in a simulated microgravity experiment of an electrorheological complex plasma. Because of the averaging effects associated with the PIV analysis technique, a mapping function is required to relate the velocity distribution measured by PIV and the original distribution. The simulation data is used to perform a rigorous evaluation of this mapping function. It is shown that the mapping function accurately reproduces (with discrepancies of under 20%) the velocity distribution of the simulation data thus providing an important validation of the PIV technique. [ABSTRACT FROM AUTHOR]

A study of dust-grain charging plays a very important role in the understanding of complex (dusty) plasma. The dust grains are charged by several different processes (e.g., electron and ion attachments, secondary electron emission, photoemission, and field electron and ion emissions), and their charge significantly influences the surrounding plasma. Our laboratory experiment based on an electrodynamic quadrupole trap allows us to investigate some of these processes on a single isolated dust grain which can be trapped and influenced with different agents for a very long time (days). In this paper, we focused on the determination of the relation between charging conditions and the field-emission mechanism because this emission limits positive charges that dust grains can acquire due to photoemission, secondary emission, or ion attachment. The field-ion-emission process is based on the field ionization of the atoms that crosses a critical distance from the grain surface. We have found that the sources of these atoms are either the surrounding gas or the ions implanted into the grain and leaving it due to diffusion. The diffusion can be described by two time constants differing by an order of magnitude. We used two sets of dust grains: gold and amorphous carbon. The experimental results are confirmed by a simple model. [ABSTRACT FROM AUTHOR]

In this paper, the thermal properties of a weakly coupled dc glow discharge dusty plasma with driven dust acoustic waves are investigated. Here, the waves are driven using a current modulation at a fixed frequency with varying amplitudes. Stereoscopic particle image velocimetry is used to measure the velocity space distribution of the dusty plasma. It is shown that, with increasing amplitude of the modulation, there is a corresponding increase in the measured kinetic temperature. In addition, there is an evidence of non-Maxwellian features in the velocity distribution. [ABSTRACT FROM AUTHOR]

Although submicrometer dust of 0.01-1 μm is a great hazard to the human being and the environment, the collection efficiency of which by using an electrostatic precipitator is still low at present. The high density ions (1.97 x 109 cm-3), which are produced by the synergistic effect of the high gas particle momentum of 9.82 x 10-22 g ∙m ∙ s-1 in the flue and ionized in the strong electric field, provide many ions for submicrometer dust charging and coagulation. In this paper, the new method of homopolarity submicrometer dust coagulation in an alternating electric field was investigated. The experimental results showed that in the conditions of reduced alternating electric field strength of 7 Td and frequency of 100 Hz, for a median particle size of 0.2-μm silicon powder, the mass percent of particles of < 0.2 μm decreased from 71% to 53%. The changing rate was 25.4%, whereas the mass changing rate of the particles of 5-10 μm increased by 1.62 times. For a median particle size of 6-μm talcum powder, the mass percent of particles of < 2 μm decreased from 22% to 11%. The changing rate was 50%, whereas particles of 5-10 μm increased by 18%. The experimental results showed that the coagulation in an alternating electric field will be an effective method to collect submicrometer dust in high velocity flow field. [ABSTRACT FROM AUTHOR]

The structure and evolution of aggregate grains formed within a plasma environment are dependent on the charge acquired by the micron-sized dust grains during the coagulation process. The manner in which the charge is arranged on developing irregular structures can affect the fractal dimension of aggregates formed during collisions, which, in turn, influences the coagulation rate and size evolution of the dust within the plasma cloud. This paper presents preliminary models for the charge and size evolution of fractal aggregates immersed in a plasma environment calculated using a modification to the orbital-motion-limited (OML) theory. Primary electron and ion currents that are incident on points on the aggregate surface are determined using a line-of-sight (LOS) approximation: only those electron or ion trajectories that are not blocked by another grain within the aggregate contribute to the charging current. Using a self-consistent iterative approach, the equilibrium charge and dipole moment are calculated for the dust aggregate. The charges are then used to develop a heuristic charging scheme, which can be implemented in coagulation models. While most coagulation theories assume that it is difficult for like-charged grains to coagulate, the OML_LOS approximation indicates that the electric potentials of aggregate structures are often reduced enough to allow significant coagulation to occur. [ABSTRACT FROM AUTHOR]

The dust-acoustic nonlinear periodic (cnoidal) waves are investigated in a positively charged dusty plasma that interacts with streaming electrons and ions. Different nonlinear evolution equations are derived using the reductive perturbation method, and their cnoidal wave solutions are obtained. The dependence of the dust-acoustic speed and the streaming densities of the ions and electrons on the cnoidal wave profiles are examined. The present model may be of interest to recognize the nonlinear waves in the magnetosphere of Jupiter. [ABSTRACT FROM PUBLISHER]

The self-gravitational instability of partially ionized dusty plasma with radiative effects of electrons and ions, dust polarization force, and dust charge fluctuation has been studied. Using basic sets of fluid equations for ion, electron, neutral, and dust components, a general dispersion relation is derived. In the dynamics of dust charge, an equilibrium dust charge inhomogeneity along with the dust charge fluctuation is also considered. It is found that the presence of radiative cooling of ions and electrons, polarization force, and dust charge fluctuation significantly affects the criterion as well as the growth rate of self-gravitational instability while the dust charge inhomogeneity and dust-neutral collisions affect only the growth rate of instability. The outcomes of this paper are useful in dusty molecular clouds. [ABSTRACT FROM AUTHOR]

We theoretically investigate the effects of the nonthermal polarization force acting on dust grains in an inhomogeneous plasma containing Maxwellian electrons, nonthermal ions, and fluid negatively charged dust grains. The effects of this polarization force are significantly modified due to the presence of the nonthermal ions. In particular, an increase of the relative fraction of the nonthermal ions leads to a decrease of the polarization parameter. The modifications arising in the propagation of weak dust-acoustic (DA) solitary waves due to the presence of this nonthermal polarization force are then analyzed. As the magnitude of the polarization force increases, the energy carried by the DA soliton experiences a depletion. [ABSTRACT FROM PUBLISHER]

Following the recent tradition of publishing peer-reviewed papers presented in the Workshop on Physics of Dusty Plasmas (WPDP), this is the seventh special IEEE TPS issue on dusty plasma physics since 2001. The topics presented in the three-day workshop included microgravity experiments (PK-4), plasma or Coulomb crystals, dust charging, dust motion and dynamics, dust growth, diagnostics of complex or dusty plasmas, wave phenomena, applications, space dust, and so on. [ABSTRACT FROM AUTHOR]

In modern information technology, mobile sensor networks (MSNs) play an important role in industrial or military applications, so sensor deployment is a key issue in MSN research. Based on wireless communication theory, hexagonal topology is known to provide the best field coverage, limited nodes, and minimal system cost. In the 2-D dusty plasma physical system, plasma particles are capable of forming a good hexagonal structure based on Yukawa system crystallization. Therefore, this strategy can be applied to node deployment algorithm in MSN applications. For this paper, we used a 2-D dusty plasma simulation in order to provide node deployment for a large sensor network, and, for better performance evaluations, adopted the Delaunay triangulation in order to determine adjacent particles of a given dust particle. Sensor deployment distributions and system performance were carefully examined by considering various values for the shielding length and the computation scale in simulations. Here, we discuss the influence of the shielding rule in Yukawa system crystallization on sensor deployment applications. Our results indicate that the algorithm leads to better field coverage with perfect hexagonal topology, good system uniformity, and lower energy consumption, and can be considered as an aid for fast deployment experiments when thousands of wireless sensors are required within a large-scale area. [ABSTRACT FROM AUTHOR]

Today, the technologies used to produce monodisperse microparticles are very expensive. Due to the wide application of monodisperse/small-dispersed microparticles in various areas of industries, their high cost, and in order to contribute to the decrease in their prime cost, we have developed a new method of production of the small-dispersed/monodisperse microparticles in the plasma of the combined radio-frequency (RF) and (dc/ac) arc discharges. The advantage of the proposed method is the production of the small-dispersed/monodisperse microparticles in the range of 1–50 \mu \textm . The dispersivity and the average size (diameter) of the small-dispersed microparticles are easily controlled by varying the parameters of the RF discharge. [ABSTRACT FROM PUBLISHER]

Aggregates immersed in a plasma or radiative environment will have charge distributed over their extended surface. Previous studies have modeled the aggregate charge using the monopole and dipole terms of a multipole expansion, with results indicating that the dipole–dipole interactions play an important role in increasing the aggregation rate and altering the morphology of the resultant aggregates. This paper examines the effect that the inclusion of the quadrupole terms has on the dynamics of aggregates interacting with each other and the confining electric fields in laboratory experiments. The results are compared with modeling aggregates as a collection of point charges located at the center of each spherical monomer comprising the aggregate. [ABSTRACT FROM PUBLISHER]

We present the results of the experimental study of the influence of dusty structures on plasma. We have studied glow discharges in neon and argon (Ar) with Al2O3 polydisperse particles and melamine-formaldehyde monodisperse particles with the diameter of ${4.83}~\mu \text{m}$. We used optical emission spectroscopy and laser-induced fluorescence methods to measure shift of excited atoms populations, which led to similar results. In most cases, the population change was negligible as compared to the inaccuracy. Al2O3 particles in Ar formed large structures which caused dramatic redistribution of radiation. In this case, spectral lines and fluorescence became 9%–50% weaker at the tube center after dusty structure formation. It might be accounted for by a decrease of electron density due to recombination on the surfaces of the particles. Near the tube wall, the radiation became brighter due to an electron temperature increase. Photographs of the discharge allowed us to calculate the radial distribution of the population shift. [ABSTRACT FROM AUTHOR]

A rigorous theoretical investigation has been made on dust-acoustic (DA) shock structures in an unmagnetized dusty plasma system whose constituents are negatively charged cold mobile dust fluid, electrons following Boltzmann distribution, and positively charged ions of two distinct temperatures following nonextensive ( $q$ ) and nonthermal distributions, respectively. In this paper, the Burgers’ equation has been derived by employing reductive perturbation technique which is valid for small but finite amplitude limit. It is observed that both the nonextensive and nonthermal ions of two distinct temperatures and dust kinematic viscosity significantly modify the basic properties (amplitudes, width, and polarities) of the DA shockwaves (DASHWs). The effects of low (high) temperature ions following nonextensive (nonthermal) and dust kinematic viscosity on DASHWs are examined both analytically and numerically. The implications of these results to some astrophysical environments and space plasmas (e.g., stellar polytropes, peculiar velocity distributions of galaxies, and collisionless thermal plasma), and laboratory dusty plasma systems are briefly mentioned. [ABSTRACT FROM PUBLISHER]

This special issue contains papers solicited at the 13th Workshop on the Physics of Dusty Plasmas held May 20???23 in Waco, TX, USA and follows the tradition of earlier workshops, which resulted in such issues in 1994, 2001, 2004, 2007, and 2010. Dusty plasmas constitute a fully developed interdisciplinary field with direct connections to astrophysics, nanoscience, fluid mechanics, and material science as defined through experimental, theoretical, and numerical studies. The field achieved an interdisciplinary research focus when the 1986 flyby of Halley's Comet and Voyager's images of Saturn's rings focused the attention of plasma physicists on a field that had previously been considered as purely planetary science. Joint efforts between these disciplines quickly led to rapid advancement in both plasma physics (e.g., discovery of dustacoustic waves, dust-ion-acoustic waves) and the planetary sciences (e.g., spokes in Saturn's rings, Jovian stream particles). The primary objectives of the 13th Workshop on the Physics of Dusty Plasmas were to provide a review of recent advancements in the field of complex plasma, define new/existing/outstanding issues and research challenges, and strengthen engagement between the field of complex plasma and other research related disciplines. Researchers from universities all over the world, including twenty-six graduate students evenly split between universities in the United States and international universities, participated in the workshop. Eighty-six paper and poster presentations were accepted covering topics including laboratory, theoretical, and computational studies of dust plasma interactions. Sixteen papers from the Waco meeting appear in this special issue covering topics across a variety of theoretical and experimental areas. Instabilities in dusty plasma systems, the manner in which such instabilities are believed to be linked to the onset of dust density or dust-acoustic waves and the mechanism by which these waves evolve and are related to the ambient plasma are reported. Dust dynamics, mass loss, and a method for employing the plasma glow to probe the plasma sheath in the vertical direction are discussed. A numerical method allowing calculation of the grain charge while including secondary electron emission and the application of this method to the lunar environment is provided. Finally techniques for stereoscopic observations, three-dimensional models of dust plasma interactions and dusty plasma experiments allowing inspection of magnetized dusty plasmas and dusty plasma environments containing chemically reactive gases are reported. [ABSTRACT FROM PUBLISHER]

In this work, the results of experiments on the dust particle synthesis process by combining two types of discharges at atmospheric pressure are presented. The experimental setup consists of two pin type copper electrodes connected to the pulsed high voltage source (spark discharge) and two copper foils wrapped around a quartz tube powered by a kilohertz high voltage sinusoidal signal [atmospheric pressure plasma jet (APP jet)]. In that case, the spark discharge serves as a precursor. It is a source of vapor and primary nanoparticles. Furthermore, these nanoparticles transported by gas flow to the region of uniform dielectric barrier discharge of the plasma jet increased in size and settled on the surface of the substrate. The results of experiments with combined discharge and with spark discharge only are compared. Particle formation and growth mechanisms were discussed. The chemical composition of the deposited particles was obtained. [ABSTRACT FROM AUTHOR]

The influence of weakly ionized dusty plasma on electromagnetic (EM) wave propagation was investigated to understand blackouts in communications during the reentry of hypersonic vehicles. Adopting the Bhatnagar–Gross–Krook (BGK) collision model and charging theory, the total complex dielectric constant of weakly ionized dusty plasma is derived considering solely: 1) a nonzero minimum velocity of the electron; 2) a contribution of the second term of the collision cross-section; and finally, 3) both 1) and 2) considered. Using the propagation matrix method, we analyzed the dielectric constant and propagation properties from our modified models and those of the traditional model for weakly ionized plasma with and without dust. The results show that, regarding EM waves, the dust-free weakly ionized plasma has a larger coefficient of reflection than weakly ionized dusty plasma. Simultaneous considering nonzero velocity and contribution of the second term of the collision cross-section significantly changed the dielectric constant and propagation properties, indicating the nonnegligible role of these two factors. Furthermore, the influence of dust size and concentration on the propagation properties of the EM wave was discussed with considering the two factors. The simulated results show that the coefficient of absorption increases and the coefficient of transmission decreases with increase in size and concentration of dust particles. [ABSTRACT FROM AUTHOR]