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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]

In the present paper, the characteristics of the head-on collision between two dust-acoustic solitary waves (DASWs) in an adiabatic dusty plasma consisting of variable negatively charged dust grains, isothermal electrons and two-temperature isothermal ions in the presence of an external oblique magnetic field are investigated. Using the extended Poincaré–Lighthill–Kuo (PLK) method, the Korteweg–de Vries (KdV) equations and the analytical phase shifts after the head-on collision of two solitary waves are derived. The effects of the magnetic field and its obliqueness, two different type of isothermal ions and the dust particles adiabaticity are discussed. It is found that these factors significantly affect the phase shifts. [ABSTRACT FROM AUTHOR]

This paper addresses the problem of the electrostatic perturbation in multi-dust-acoustic plasma species with Z-pinches using various mixtures. It is demonstrated that the plasma shell separates into two distinct annuli, which implode concentrically. This phenomenon is quantitatively explained using a semi hydrodynamic model. In this case, stability is investigated and an expression for the growth rate of Rayleigh-Taylor type instability is presented. The growth rate is found to be independent of the degree of dust plasma compressibility, and somewhat reduced in the presence of an ion mixture. [ABSTRACT FROM AUTHOR]

This paper investigated chaos control of four-dimensional autonomous van der Pol Mathieu (vdPM) system that describes dust-charge fluctuation in dusty plasma. A recursive backstepping scheme was employed to design a single control input that effectively controlled the undesirable unstable behaviour of the vdPM system. Both theoretical analysis and numerical simulations were presented to illustrate the effectiveness of the proposed control scheme. [ABSTRACT FROM AUTHOR]

This paper presents radial distribution functions of dust particles obtained experimentally in dc and rf discharges. Pressure and interaction energy of dusty particles were calculated on the basis of these functions. The Langevin dynamics computer simulation for each experiment was performed. The comparisons with computer simulations are made. [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 collisional hydrodynamic equations for electrons, ions, and dust particles in dusty plasmas are derived from the kinetic equations [V. N. Tsytovich and U. de Angelis, Phys. Plasmas 6, 1093 (1999)] which consistently take into account the elastic and inelastic (charging) collisions of plasma particles with dust and the effects of dust charge fluctuations. These equations are valid in the parameter regime where the collisions of plasma particles with dust dominate with respect to the binary plasma collisions. New expressions for the fluid collision frequencies, transport coefficients, viscosity, and ion drag are found and compared with previous results. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The article discusses that second rate inventions, where even less is known about the design and operation parameters. Though hundreds of such inventions were patented during the last 150, all of them are buried on the shelves of patent offices. Condensed plasmoid-based mechanical inventions "fueled" by the ambient vapor in the air. As usual, these spark-based rotary devices all resemble Wimhurst devices— electrostatic influence machines.

Two omnipresent ingredients of the Universe are plasmas and charged dust. The interplay between these two has opened up a new and fascinating research area, that of dusty plasmas, which are ubiquitous in different parts of our solar system, namely planetary rings, circumsolar dust rings, the interplanetary medium, cometary comae and tails, as well as in interstellar molecular clouds, etc. Dusty plasmas also occur in noctilucent clouds in the arctic troposphere and mesosphere, cloud-to-ground lightening in thunderstorms containing smoke-contaminated air over the United States, in the flame of a humble candle, as well as in microelectronic processing devices, in low-temperature laboratory discharges, and in tokamaks. Dusty plasma physics has appeared as one of the most rapidly growing fields of science, besides the field of the Bose–Einstein condensate, as demonstrated by the number of published papers in scientific journals and conference proceedings. In fact, it is a truly interdisciplinary science because it has many potential applications in astrophysics (viz. in understanding the formation of dust clusters and structures, instabilities of interstellar molecular clouds and star formation, decoupling of magnetic fields from plasmas, etc.) as well as in the planetary magnetospheres of our solar system [viz. Saturn (particularly, the physics of spokes and braids in the B and F rings), Jupiter, Uranus, Neptune, and Mars] and in strongly coupled laboratory dusty plasmas. Since a dusty plasma system involves the charging and dynamics of massive charged dust grains, it can be characterized as a complex plasma system providing new physics insights. In this paper, the basic physics of dusty plasmas as well as numerous collective processes are discussed. The focus will be on theoretical and experimental observations of charging processes, waves and instabilities, associated forces, the dynamics of rotating and elongated dust grains, and some nonlinear struct... [ABSTRACT FROM AUTHOR]

It is widely recognized that in a typical dusty plasma encountered in the laboratory or outer space, the dust component is in a strongly coupled state because the interaction energy of neighboring dust particles due to shielded Coulomb (“Yukawa”) forces is much larger than their thermal energy. Low frequency collective modes involving the motion of dust particles are therefore greatly influenced by the strong correlation effects in the dust component. In this paper a dispersion relation for low-frequency collective modes using a generalized hydrodynamics model for the dust component has been derived. Strong correlation effects are described in terms of viscoelastic transport coefficients and a finite relaxation time for the memory kernel. Novel collective effects such as new corrections to dispersion terms for longitudinal dust acoustic waves and the existence of transverse shear waves supported by strong correlations have been identified. New physical processes involving nonuniform charge number equilibria and delayed charging effects which could drive the shear wave instability have also been studied. A report on some new experiments where self-excited transverse shear modes are seen when the dust component of the plasma is in a strongly correlated fluid-like state is also presented. [ABSTRACT FROM AUTHOR]

The dust-dust collision integrals found in the kinetic theory of dusty plasmas [Tsytovich and de Angelis, Phys. Plasmas 6, 1093 (1999); 7, 554 (2000)] are analyzed. Analytic expressions are derived and numerical results are given for the case of thermal distributions to assess their importance and dependence on dusty plasma parameters. Modifications of Debye screening by collective dust effects are obtained. A study of the forces between two test dust particles is presented and the appearance of weakly screened attraction forces at distances larger than the Debye screening length is analyzed. These forces are related to the collective shadow effect in dust charging and operate at distances larger than the previously known noncollective shadow attraction forces. The dependence of the collective attraction forces on dust temperature is analyzed. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The time evolution of the plasma distribution functions (electrons and ions) in dusty plasmas is found solving numerically the equations of the kinetic theory of dusty plasmas [Tsytovich and de Angelis, Phys. Plasmas 6, 1093 (1999); 7, 554 (2000)]. The role and importance of the plasma source and particle diffusion are investigated. The "equilibrium" distributions (asymptotic solutions) are used to calculate the static screening of a dust particle, and the difference with the usual result (Debye screening) of a three-component plasma is shown for various parameter regimes. © 2001 American Institute of Physics. [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]

In this paper, linear and nonlinear coupling of kinetic Alfven and acoustic waves has been studied in a dusty plasma in the presence of trapping and self-gravitation effects. In this regard, we have derived the linear dispersion relations for positively and negatively coupled dust kinetic Alfven-acoustic waves. Stability analysis of the coupled dust kinetic Alfven-acoustic wave has also been presented. The formation of solitary structures has been investigated following the Sagdeev potential approach by using the two-potential theory. Numerical results show that the solitary structures can be obtained only for sub-Alfvenic regimes in the scenario of space plasmas. [ABSTRACT FROM AUTHOR]

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]

The article states that various aspects of LENR were discovered in the early part of the twentieth century. Transient dusty plasma offers higher local accelerations and energy levels at a small percentage of the energy expenditure of modern particle accelerators. Information is offered on inventions that created electric energy.

Analytical expression for wake potential is obtained in a 2-D magnetized complex plasma using Linear Response Theory. The dynamics of the system is explored at moderate to relatively high magnetic field limit. A 2-D expression for wake potential is obtained and the variation in the strength of the wake potential is explored at different magnetic fields in moderate regime and for ion flow speed in supersonic regime. The theory also facilitates the understanding on the nature of wake potential in relatively high magnetic field limit. Molecular Dynamics simulation is performed to see the role of wake potential developed in this paper on governing the structural property of strongly coupled dusty plasma in presence of moderate to relatively strong magnetic field. Graphical abstract: [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]

Towards the investigation of polydisperse complex plasmas, the generation of binary mixtures is a first and important step. In this paper, the requirements for the generation of two-dimensional binary mixtures are discussed and first experiments are presented. In particular, the material dependent mass loss of the particles is taken into account by monitoring the charge-to-mass ratio of both species using a resonance method. The charge ratio q1/q2 of the species is determined and the spacial properties of the two-component crystals are examined and compared to numerical simulations. [ABSTRACT FROM AUTHOR]

In this paper, we have investigated the effect of secondary electron emission on nonlinear propagation of dust acoustic waves in a complex plasma where equilibrium dust charge is negative. The primary electrons, secondary electrons, and ions are Boltzmann distributed, and only dust grains are inertial. Electron-neutral and ion-neutral collisions have been neglected with the assumption that electron and ion mean free paths are very large compared to the plasma Debye length. Both adiabatic and nonadiabatic dust charge variations have been separately taken into account. In the case of adiabatic dust charge variation, nonlinear propagation of dust acoustic waves is governed by the KdV (Korteweg-de Vries) equation, whereas for nonadiabatic dust charge variation, it is governed by the KdV-Burger equation. The solution of the KdV equation gives a dust acoustic soliton, whose amplitude and width depend on the secondary electron yield. Similarly, the KdV-Burger equation provides a dust acoustic shock wave. This dust acoustic shock wave may be monotonic or oscillatory in nature depending on the fact that whether it is dissipation dominated or dispersion dominated. Our analysis shows that secondary electron emission increases nonadiabaticity induced dissipation and consequently increases the monotonicity of the dust acoustic shock wave. Such a dust acoustic shock wave may accelerate charge particles and cause bremsstrahlung radiation in space plasmas whose physical process may be affected by secondary electron emission from dust grains. The effect of the secondary electron emission on the stability of the equilibrium points of the KdV-Burger equation has also been investigated. This equation has two equilibrium points. The trivial equilibrium point with zero potential is a saddle and hence unstable in nature. The nontrivial equilibrium point with constant nonzero potential is a stable node up to a critical value of the wave velocity and a stable focus above it. This critical value increases with increasing secondary electron emission. Thus, in the presence of secondary electron emission, higher velocity shock waves are monotonic. The results have been numerically explained considering the presence of Al2O3 dust grains in the plasma. [ABSTRACT FROM AUTHOR]

In this paper, we discuss the relations between the exact shape of interparticle interactions in complex (dusty) plasmas and the dispersion relation of the longitudinal collective mode. Several representative repulsive potentials, predicted previously theoretically, are chosen, and the corresponding dispersion relations are calculated using the quasi-crystalline approximation. Both weakly coupled and strongly coupled regimes are considered. It is shown that the long-wavelength portions of the dispersion curves can be sensitive to the long-range asymptote of the interaction potential. This can be used to discriminate between different interaction mechanisms operational in complex plasmas experimentally. Main requirements are briefly discussed. [ABSTRACT FROM AUTHOR]

In this paper, the effect of ion radiative cooling on the gravitational instability of dusty plasma is studied, incorporating dust charge fluctuation with dust-neutral, neutral-ion, and ion-neutral collisions. The basic equations are linearized using normal mode analysis to obtain a general dispersion relation. The general dispersion relation is analytically and numerically discussed to explain the role of ion radiative cooling in the structure formation through gravitational instability. The Jeans collapse criteria are found to be modified due to ion and electron radiative cooling, dust charge fluctuations, and collisions effects. It is determined from the analytical and numerical calculations that the support of radiative cooling of ions drives thermal fluctuations and gives instability to the system. The electron cooling effect remains dominating over ion cooling effect, and thus, it enhances the collapse more efficiently than ion cooling effect. Although the radiative cooling is slow, it may precede the collapse in molecular cloud, which further leads to the structure formation. The present work is relevance for the structure formation in the molecular cloud. [ABSTRACT FROM AUTHOR]

One of the main challenges in modeling compositional transport in tight formations is to include the complex interaction of chemical species with rock surfaces. Such interactions result in compositional variations near the surfaces, which can significantly affect the compositional diffusive transport through tight pores. This paper presents the application of the Multicomponent Potential Theory of Adsorption (MPTA) for the fluid compositions in the central and near-wall sorbed layers subject to a wall chemical potential. The two-layer approximation of MPTA is implemented in the diffusive transport simulation that computes the mass transfer driven by fugacity gradient based on the dusty gas model for the central and sorbed layers of pores. This simulator uses a partially implicit formulation to solve the multiphase multicomponent mass transfer equations including the sorbed layer. The main novelty of this paper lies in the detailed analysis of the interplay between fluid components and rock surfaces, which became possible with the two-layer MPTA coupled with multicomponent diffusion. The diffusion simulation for a ternary case of methane, n-butane, and n-decane with the approximate MPTA shows that the sorption and capillary pressure can cause the compositional segregation between the central and sorbed layers. The segregation enhances the rates of methane injection and n-decane production in their counter-current diffusion. Methane (the lightest) is transported deep into the reservoir by diffusing through the central layer while n-decane (the heaviest) is diffused primarily through the sorbed layer. n-Butane (the intermediate) does not show preferential partitioning into either layer, resulting in relatively inefficient transport. In the absence of sorption and capillary pressure, the countercurrent diffusion occurs between methane (the lightest) and n-butane (the intermediate) while n-decane (the heaviest) remains nearly immobile. That is, whether the simulation considers the surface-fluid interactions can substantially affect the compositional transport (e.g., produced fluid composition) through tight porous media. The multicomponent Langmuir model is often used for computing the sorbed excess in micropores. However, results show that the Langmuir model becomes physically inconsistent at high pressures because it predicts a monotonically increasing function of pressure. The new approach developed in this research is sufficiently flexible and reasonably accurate for modeling multicomponent sorption at high pressures. • Potential theory was applied to multicomponent sorption and diffusion. • A pore was divided into two layers for efficient calculation of sorption. • The dusty gas model was used for diffusion in the two layers. • Simulation cases showed the impact of sorption on component transport. • Segregated countercurrent diffusion was predicted in the two layers. [ABSTRACT FROM AUTHOR]

In this paper, we have investigated the effects of Bohm potential on the low frequency wave propagation in a dense non-degenerate dusty magnetoplasma. We have employed two potential theory to study the quantum modification of kinetic Alfvén wave on a dust acoustic velocity branch. The linear dispersion relation and growth rate of instability of dust kinetic Alfvén wave are obtained by incorporating Bohm quantum potential in the linearized Vlasov model. It is found that unlike in classical plasma, the presence of CQ which arises through the Bohm potential, tends to enhance the dispersion of the particles, while the growth rates are suppressed. The importance and relevance to compact astrophysical objects and space dusty plasma environments is also pointed out. [ABSTRACT FROM AUTHOR]

This paper assesses the feasibility of observing the gyro-phase drift in the Auburn Magnetized Dusty Plasma Experiment [MDPX, described by Thomas et al., Plasma Phys. Controlled Fusion 54, 124034 (2012)]. The gyro-phase drift arises when a dust grain does not instantaneously reach the in-situ-equilibrium grain charge during gyro-synchronous grain-charge modulation. Koepke et al. [J. Plasma Phys. 79, 1099 (2013)] first suggested using MDPX to observe the gyro-phase drift, and here we use a single-particle trajectory tracker with an iterative velocity solver, using a fixed timestep for grain motion and an adaptive time step for grain charging, to consider all relevant dust grain forces to assess gyro-phase drift arising from gradual inhomogeneity. Additionally, the semi-analytic theory developed by Walker et al. [J. Plasma Phys. 80, 395 (2014)] predicts dust grain motion in abrupt inhomogeneity for MDPX-relevant conditions. We compare three grain-charging models with each other and with the single-particle trajectory tracker and found to predict distinctly different trajectories depending on the treatment of neutral drag and flowing ions. The measurement thresholds for Particle Tracking Velocimetry permit gyro-phase drift detection in MDPX for the abrupt inhomogeneity, given sufficiently large enough UV photoelectron flux (fuv/[nevthe]>0.01) and low enough neutral gas pressure (less than one mTorr). The Orbit-Motion-Limited charge model and the charge models developed by Patacchini et al. [Phys. Plasmas 14, 062111 (2007)] and Gatti and Kortshagen [Phys. Rev. E 78, 046402 (2008)] can, in principle, be distinguished by gyro-phase drift in the abrupt inhomogeneity, but large magnetic fields, large UV photoelectron flux, and low neutral gas pressure are required. Gyro-phase drift for a gradual inhomogeneity in the ratio ne/ni, arising from the presence of a radial electric field, is predicted to be undetectable. [ABSTRACT FROM AUTHOR]

The streaming of ions through the dust particles significantly modifies the repulsive Debye-Hückel type of interaction in the sheath and pre-sheath regions and leads to the appearance of oscillatory and attractive wake type interaction. In this paper, we investigate the formation of dust-ion acoustic solitary and shock waves in the presence of streaming ions in a strongly coupled dusty plasma. The generalized hydrodynamic equation is used to describe the dust dynamics, and the dust-dust interaction has been taken into account via the electrostatic pressure term. The novel feature of the present study is the incorporation of both the repulsive and attractive interactions in the electrostatic pressure term. The flow of ions along the vertical direction in the sheath/presheath region of the plasma brings asymmetry to the dust dynamics, which has been carefully handled while considering the effect of strong coupling in the formation of nonlinear structures in such plasma. The study reveals that the ion streaming velocity has a crucial role in controlling the nonlinear coherent structures. [ABSTRACT FROM AUTHOR]

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]

PIV images of a dusty plasma (obtained after averaging 50 images) flow in a horizontal plane at different vertical locations of confined dust grains in a potential well. (a) Topmost dust grains (b) 2mm below the topmost dust grains plane, (c) 4mm lower than the topmost dust grains plane, (d) 6mm lower than the topmost dust grains plane. Fig. 5 of the paper by Mangilal Choudhary. https://doi.org/10.1002/ctpp.202300072. [Extracted from the article]

Particle contamination due to plasma processing motivates the design of a method of electrically lifting particles in a time interval after a plasma's power is turned off. Small solid dust particles have electric charges that are not frozen until a late stage of the plasma afterglow. Beyond that time, before they fall to a surface below and cause defects, particles can be lifted in a controlled manner by applying an appropriate direct-current (DC) electric field, as we demonstrate experimentally. A few milliseconds after an argon plasma's capacitively coupled radio-frequency power is switched off, a vertical DC electric field is applied. Thereafter, video imaging shows that the falling of the particles is slowed or stopped altogether, depending on the magnitude of the upward electric force. [ABSTRACT FROM AUTHOR]

We investigate the effect of nonthermal electrons modeled by two non-Maxwellian distribution functions, i.e., the (r, q) and Cairn's distributions on the formation of dust acoustic (DA) solitons in an un-magnetized dusty plasma by incorporating the effect of dust streaming. We adopt the pseudopotential technique to obtain solitary wave solutions from fluid equations. It is seen that only rarefactive soliton can be obtained in such plasmas where ions are considered Boltzmannian and electrons non-Maxwellian. We find that soliton characteristics are strongly dependent on the nonthermal spectral indices r, q, and α and dust temperature Td. For (r, q) distribution, it is found that soliton amplitude increases but width decreases when the positive (negative) value of r decreases (increases). For Cairn's distribution, we find that with the increase in α, soliton amplitude decreases. In space environments, such as cometary tails, solar wind, and Earth's magnetosphere, where non-Maxwellian populations of electrons are present, our theoretical results show that the amplitude of soliton remains smaller than the Maxwellian case. Thus, Maxwellian distribution overestimates the soliton amplitude in such space environments. Therefore, we feel that our results will better interpret the results of observations, from cometary tails, and other space plasmas where nonlinear DA structures are likely to be observed. [ABSTRACT FROM AUTHOR]

The influence of mineral dust deposition on soil formation in the mountain critical zone was evaluated at six sites in southwestern North America. Passive samplers collected dust for 2 years, and representative soil and rock were gathered in the vicinity of each dust sampler. All materials (dust, soil, and rock) were analyzed to determine their mineralogy (with X-ray diffraction), geochemistry (with inductively coupled plasma mass spectrometry (ICP-MS)), and radiogenic isotope fingerprint (87Sr/86Sr and εNd). In addition, the grain size distribution of dust and soil samples was determined with laser scattering, and standard soil fertility analysis was conducted on the soil samples. Results reveal that minerals present in the dust but absent in the local bedrock are detectable in the soil. Similarly, the geochemistry and isotopic fingerprint of soil samples are more similar to dust than to local bedrock. End-member mixing models evaluating soil as a mixture of dust and rock suggest that the fine fractions of the sampled soils are dominated by dust deposition, with dust contents approaching 100 %. Dust content is somewhat higher in soils compared to bedrock types more resistant to weathering. These results emphasize the dominant control that mineral dust deposition can exert on pedogenesis in the mountain critical zone. [ABSTRACT FROM AUTHOR]

Solar Orbiter is equipped with electrical antennas performing fast measurements of the surrounding electric field. The antennas register high-velocity dust impacts through the electrical signatures of impact ionization. Although the basic principle of the detection has been known for decades, the understanding of the underlying process is not complete, due to the unique mechanical and electrical design of each spacecraft and the variability of the process. We present a study of electrical signatures of dust impacts on Solar Orbiter's body, as measured with the Radio and Plasma Waves electrical suite. A large proportion of the signatures present double-peak electrical waveforms in addition to the fast pre-spike due to electron motion, which are systematically observed for the first time. We believe this is due to Solar Orbiter's unique antenna design and a high temporal resolution of the measurements. The double peaks are explained as being due to two distinct processes. Qualitative and quantitative features of both peaks are described. The process for producing the primary peak has been studied extensively before, and the process for producing the secondary peak has been proposed before for Solar Terrestrial Relations Observatory (STEREO), although the corresponding delay of 100–300 µ s between the primary and the secondary peak has not been observed until now. Based on this study, we conclude that the primary peak's amplitude is the better measure of the impact-produced charge, for which we find a typical value of around 8 pC. Therefore, the primary peak should be used to derive the impact-generated charge rather than the maximum. The observed asymmetry between the primary peaks measured with individual antennas is quantitatively explained as electrostatic induction. A relationship between the amplitude of the primary and the secondary peak is found to be non-linear, and the relation is partially explained with a model for electrical interaction through the antennas' photoelectron sheath. [ABSTRACT FROM AUTHOR]

On our previous soliton solutions [H. L. Zhen et al., Phys. Plasmas 21, 073709 (2014)] of an extended Zakharov-Kuznetsov equation, El-Tantawy and Wazwaz [Phys. Plasmas 25, 104701 (2018)] have commented that there exists another soliton solution without any constraint for the parameters. In this Reply, we first state the correctness of our previous solutions, and then, we point out the difference between the two solutions: one is from our previous paper [H. L. Zhen et al., Phys. Plasmas 21, 073709 (2014)] and the other is from the comment by El-Tantawy and Wazwaz [Phys. Plasmas 25, 104701 (2018)]. Meanwhile, we also investigate the connections between our work and some recent literature studies. [ABSTRACT FROM AUTHOR]

Our prime objective of this paper is to examine the parametric regimes for the existence and polarity of dust acoustic double layers (DADLs) and its solitary structures arising from a magnetized self-gravitating opposite polarity dust-plasma (OPDP) model. The constituents of the OPDP model are two species of positively and negatively charged dust grains, Maxwellian electrons and kappa distributed ions. Contributions of gravitational force only on dust grains are taken into account. For weakly nonlinear analysis, the multiple time scale technique has been used to construct the extended Korteweg-de Vries (E-KdV) and modified Korteweg-de Vries (M-KdV) equations. They pinpoint the evolution of DADLs and solitary structures associated with dust acoustic (DA) mode, respectively. The relevant configurational parameters in our study include the superthermality of ions (κ), obliqueness of propagation (ϑ), ion concentration (δi), static magnetic field B0 (via ωcp, ωcn), and self-gravitational field (via γ), as well as the density (μ0), charge (α), and mass (β) ratio of positive to negative dust species. The proposed OPDP model permits positive and negative double layer polarities, while higher order nonlinear equation dictates us only positive polarity solitary structures. The main modification due to an increase in self-gravitational field (via γ) is an enhancement in the spatial width of double layers, yet leaving their amplitude, phase speed, and polarity practically unaffected. With enhanced superthermality and other intrinsic parameters in OPDP model, there is an opposite trend in both amplitude and width of double layers, while the amplitude and the width of solitary waves (via M-KdV equation) undergo the identical behaviors. In particular, the amplitude of solitary waves manifests monotonic behavior for permissible range of obliqueness ϑ, whereas this scenario is acceptable to only width of double layers. The results are discussed in the context of laboratory and astrophysical plasma environments (e.g., cometary tails, Earth's mesosphere, etc.). [ABSTRACT FROM AUTHOR]

The effects of dust size distribution and dust charge fluctuation of dust grains on the small but finite amplitude nonlinear dust ion-acoustic shock waves, in an unmagnetized multi-ion dusty plasma which contains negative ions, positive ions and electrons, are studied in this paper. A Burgers equation and its stationary solutions are obtained by using the reductive perturbation method. The analytical and numerical results show that the height with polynomial dust size distribution is larger than that of the monosized dusty plasmas with the same dust grains, but the thickness in the case of different dust grains is smaller than that of the monosized dusty plasmas. Furthermore, the moving speed of the shock waves also depend on different dust size distributions. [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]

Although most experiments in complex plasmas correspond to non-linear grain screening, the theoretical models of non-linear screening have not been checked experimentally. Scattering of electromagnetic waves on a single nonlinearly screened dust grain in plasmas can serve as one of effective methods for investigation of non-linear screening. In present paper we have developed a theory for electromagnetic wave scattering that includes both the effect of coherency of scattering for long wave range and the loss of coherency with a decrease of the wave length. It is valid for arbitrary non-linearity in screening and demonstrates that the loss of coherency occurs for wave length less then the characteristic screening length for non-linear screening being usually substantially larger than the linear Debye screening length. The effect is illustrated numerically using the most popular model of non-linear screening. The dependence of the cross-section of scattering on parameter of non-linearity in screening is calculated numerically. The loss of coherency in scattering by a single grain can serve as effective diagnostic for checking the theoretical models of non-linear screening. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Linear and nonlinear dust-acoustic (DA) waves are studied in a collisionless, unmagnetized and dissipative dusty plasma consisting of negatively charged dust grains, Boltzmann-distributed electrons, and nonthermal ions. The normal mode analysis is used to obtain a linear dispersion relation illustrating the dependence of the wave damping rate on the carrier wave number, the dust viscosity coefficient, the ratio of the ion temperature to the electron temperatures, and the nonthermal parameter. The plasma system is analyzed nonlinearly via the reductive perturbation method that gives the KdV-Burgers equation. Some interesting physical solutions are obtained to study the nonlinear waves. These solutions are related to soliton, a combination between a shock and a soliton, and monotonic and oscillatory shock waves. Their behaviors are illustrated and shown graphically. The characteristics of the DA solitary and shock waves are significantly modified by the presence of nonthermal (fast) ions, the ratio of the ion temperature to the electron temperature, and the dust kinematic viscosity. The topology of the phase portrait and the potential diagram of the KdV-Burgers equation is illustrated, whose advantage is the ability to predict different classes of traveling wave solutions according to different phase orbits. The energy of the soliton wave and the electric field are calculated. The results in this paper can be generalized to analyze the nature of plasma waves in both space and laboratory plasma systems. [ABSTRACT FROM AUTHOR]

This special issue of CPP is devoted to the memory of an outstanding Russian physicist - Academician Vladimir Fortov (January 23, 1946-November 29, 2020). He made outstanding contributions to the physics of extreme states of matter and to the physics of high energy densities, the physics of shock and detonation waves, thermal physics, chemical physics, energetics, and other areas of physics and technology. Under Vladimir's leadership, a series of pioneering experimental and theoretical studies of the structural and dynamic properties of plasma-dust crystals was carried out in a wide range of temperatures and pressures. [Extracted from the article]

Both the linear and the nonlinear magnetosonic wave in a multi-component dusty plasma are studied in the present paper. The dependence of the dispersion relation of the linear waves on the dust size distribution are given. It seems that the larger the difference between the maximum and the minimum radius of the dust grains, the lower the wave frequency for all cases of the dust size distribution. Furthermore, it is noted that the width, the amplitude and the propagation velocity of the KdV solitary wave depend on the dust size distribution, especially it depend on whether the number density of the larger sized dust grain is larger or smaller than that of the smaller sized dust grain. For the power law dust size distribution, the width and the propagation velocity of the KdV solitary wave between the maximum and the minimum radius of the dust grains is larger than that of mono-sized dusty plasma. [ABSTRACT FROM AUTHOR]

Theoretical and numerical investigations are carried out for the instability of the dust–acoustic waves (DAWs) under the transverse perturbation in a magnetized dusty plasma with two-temperature nonthermal ions. By the reductive perturbation technique, the Zakharov–Kuznetsov (ZK) equation and modified ZK equation of the DAWs are derived. Under the higher-order transverse perturbations, the instability growth rate of the soliton solutions of the ZK equations is studied. It is found that the most unstable wave mode exists in system. It is also noted that solitary waves are unstable when the ratio of the perturbation wave length to solitary wave width in the experimental coordinate is larger than a certain critical value. [ABSTRACT FROM AUTHOR]

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]

In this paper, our attention is first concentrated on obliquely propagating properties of low-frequency (ω ≪ ωcd) "fast" and "slow" dust acoustic waves, in the linear regime, in dusty electronegative plasmas with Maxwellian electrons, kappa distributed positive ions, negative ions (following the combination of kappa-Schamel distribution), and negatively charged dust particles. So, an explicit expression for dispersion relation is derived by linearizing a set of dust-fluid equations. The results show that wave frequency ω in long and short-wavelengths limit is conspicuously affected by physical parameters, namely, positive to negative temperature ion ratio (βp), trapping parameter of negative ions (μ), magnitude of the magnetic field B0 (via ωcd), superthermal index (κn,κp), and positive ion to dust density ratio (δp). The signature of the penultimate parameter (i.e., κn) on wave frequency reveals that the frequency gap between the modes reduces (escalates) for kcr (k>kcr), where kcr is critical wave number. Alternatively, for weakly nonlinear analysis, reductive perturbation theory has been used to construct 1D and 3D Schamel Korteweg-de Vries (S-KdV) equations, whose nonlinearity coefficient prescribes only compressive soliton for all parameter values of interest. The survey manifests that deviation of ions from Maxwellian behavior leads intrinsic properties of solitary waves to be evolved in opposite trend. Additionally, at lower proportion of trapped negative ions, solitary wave amplitude mitigates, whilst the trapping parameter has no effect on both spatial width and the linear wave. The results are discussed in the context of the Earth's mesosphere of dusty electronegative plasma. [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]

Dust structuring is a natural and universal process in complex plasmas. The scattering of electromagnetic waves by dust structures is governed by the factor of coherency, i.e., the total number of coherent electrons in a single structure. In the present paper, we consider how the factor of coherency changes due to additional pulse electron heating and show that it obeys a hysteresis. After the end of the pulse heating, the scattering intensity differs substantially from that before heating. There are three necessary conditions for scattering hysteresis: first, the radiation wavelength should be larger than the pattern (structure) size; second, the total number of coherent electrons confined by the structure should be large; and third, the heating pulse duration should be shorter than the characteristic time of dust structure formation. We present the results of numerical calculations using existing models of self-consistent dust structures with either positively or negatively charged dust grains. It is shown that, depending on the grain charge and the ionization rate, two types of hysteresis are possible: one with a final increase of the scattering and the other with a final decrease of the scattering. It is suggested that the hysteresis of coherent scattering can be used as a tool in laboratory experiments and that it can be a basic mechanism explaining the observed hysteresis in radar scattering by noctilucent clouds during active experiments on electron heating in mesosphere. [ABSTRACT FROM AUTHOR]

In this paper the results of studying of the electron temperature of buffer and complex plasmas in mixtures of noble gases (helium + argon) in capacitively coupled radiofrequency (CCRF) discharge are presented. The optical properties of dusty plasma in argon, helium and their mixtures have been studied using optical diagnostic methods. Based on spectral lines of plasma forming gases, the dependence of the electron temperature on gas pressure and discharge power has been determined. The axial distribution of electron temperature in the interelectrode gap has been measured. Measurements have been made using an RF compensated electric probe. The comparison of the experimental results shows that admixture of a small amount of argon to helium leads to a decrease in the electron temperature of buffer plasma. The presence of dust particles in the plasma causes an increase in the electron temperature. [ABSTRACT FROM AUTHOR]