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When a high-speed spacecraft returns to the atmosphere, a plasma sheath is formed on its surface. This causes electromagnetic waves to be reflected and absorbed. In this paper, a single-layer medium matrix transport model is used to derive expressions for the reflectivity, transmittance and attenuation values of electromagnetic waves. The electron density distribution is also modelled and the effects of electron density, plasma thickness, particle collision frequency, and magnetic field strength on the reflectivity as well as the transmittance of electromagnetic waves are discussed visually using three-dimensional images. Finally, the reflectivity and transmittance of electromagnetic waves propagating in a dust-free plasma are analyzed, with emphasis on comparing the effects of different media on the reflectivity and transmittance of electromagnetic waves. In summary, the relevant research can provide some theoretical references for propagation science. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Dust Acoustic Solitary Waves in Dusty Plasma With Nonthermal Ions," by Frank Verheest and colleagues that was published in the February 11, 2010 issue.

The exosphere of Mercury, which has much in common with the exosphere of the Moon, can also contain suspended dust particles, which, under the action of intense solar radiation, acquire positive charges and form one of the components of the dusty plasma system. In addition to dust particles, there are photoelectrons above the planet surface, formed as a result of interaction of solar radiation with the planet surface, as well as with suspended dust particles. Mercury, unlike the Moon, has its own magnetosphere, which affects the parameters of dusty plasma system. The dusty plasma parameters near the Mercury surface can vary depending on the distance from the planet to the Sun, which considerably changes when the planet moves along the elongated orbit, and also depending on the localization of the region under consideration on the planet surface. Thus, near the magnetic poles, the solar wind can reach the planet surface, which must be taken into account when determining the plasma parameters. Far from the magnetic poles, the effect of the solar wind can be neglected. In the dusty plasma near the surface of Mercury, one can expect the development of linear and nonlinear wave processes. In this paper, nonlinear waves are considered, namely, dust acoustic solitons and nonlinear periodic waves. The profiles of potentials of high-amplitude solitons and nonlinear periodic waves are obtained, as well as the soliton amplitudes as functions of the altitude above the planet surface and soliton velocity. [ABSTRACT FROM AUTHOR]

In this paper, non-linear propagation of oscillatory and monotonous DIA shocks in dusty plasma with dust charge fluctuations and small isothermal deviation of electrons is considered. The modified-Korteweg-de Vries–Burger (m-KdVB) equation can be derived by using the reductive perturbation (R-P) method. The variational principle and the conservation laws of the m-KdVB equation are constructed by introducing two special functions. A nonlinear self-adjoint classification of the m-KdVB equation is presented. Based on the Ibragimov's theorem, conservation laws for m-KdVB equation are established. We also study the m-KdVB equations by improved tan ψ (χ) 2 -expansion method. Abundant dark, singular and periodic optical solitons solutions of the model are constructed. Furthermore, additional graphical simulations were performed using mathematica to see the behavior of these solutions. With the help of bifurcation theory of planar dynamical systems, we study bifurcation and phase portrait analysis of traveling wave solution of the m-KdVB equation. [ABSTRACT FROM AUTHOR]

Since the first automatic missions to the Moon, the activity of dust particles from atmosphereless bodies has been recorded. Since then, a lot of theoretical and experimental studies of this effect have been carried out, but at present there is no clear understanding of the influence of external actions on the dynamics of this phenomenon. This paper presents the results of experiments to determine the effect of hard UV radiation on the activity of dust particles, which makes a significant contribution to particle dynamics. The result of determining the conditions for particle removal from the surface is in accordance with theoretical calculations. [ABSTRACT FROM AUTHOR]

The Plasma Wave Investigation (PWI) aboard the BepiColombo Mio (Mercury Magnetospheric Orbiter, MMO) will enable the first observations of electric fields, plasma waves, and radio waves in and around the Hermean magnetosphere and exosphere. The PWI has two sets of receivers (EWO with AM2P, SORBET) connected to two electric field sensors (MEFISTO and WPT) and two magnetic field sensors (SCM: LF-SC and DB-SC). After the launch on October 20, 2018, we began initial operations, confirmed that all receivers were functioning properly, and released the launch locks on the sensors. Those sensors are not deployed during the cruising phase, but the PWI is still capable performing magnetic field observations. After full deployment of all sensors following insertion into Mercury orbit, the PWI will start its measurements of the electric field from DC to 10 MHz using two dipole antennae with a 32-m tip-to-tip length in the spin plane and the magnetic field from 0.3 Hz to 20 kHz using a three-axis sensor and from 2.5 kHz to 640 kHz using a single-axis sensor at the tip of a 4.5-m solid boom extended from the spacecraft's side panel. Those receivers and sensors will provide (1) in-situ measurements of electron density and temperature that can be used to determine the structure and dynamics of the Hermean plasma environment; (2) in-situ measurements of the electron and ion scale waves that characterize the energetic processes governed by wave–particle interactions and non-MHD interactions; (3) information on radio waves, which can be used to remotely probe solar activity in the heliocentric sector facing Mercury, to study electromagnetic-energy transport to and from Mercury, and to obtain crustal information from reflected electromagnetic waves; and (4) information concerning dust impacts on the spacecraft body detected via potential disturbances. This paper summarizes the characteristics of the overall PWI, including its significance, its objectives, its expected performance specifications, and onboard and ground data processing. This paper also presents the detailed design of the receiver components installed in a unified chassis. The PWI in the cruise phase will observe magnetic-field turbulence during multiple flybys of Earth, Venus, and Mercury. After the Mercury-orbit insertion planned at the end of 2025, we will deploy all sensors and commence full operation while coordinating with all payloads onboard the Mio and MPO spacecraft. [ABSTRACT FROM AUTHOR]

Dust ion acoustic waves (DIAWs) are investigated analytically in the framework of damped forced Korteweg–de Vries–Burgers (DFKdVB) equation in an unmagnetized collisional dusty plasma consisting of negatively charged stationary dust grains, positively charged ions and q-nonextensive distributed electrons. Reductive perturbation technique is used to obtain the DFKdVB equation for DIAWs. The effects of different physical parameters such as the entropic index (q), ratio of unperturbed number densities of electrons and ions (μ) , dust ion collision frequency (ν id 0) , kinematic viscosity ( η 0 ), the speed of the traveling wave (M 0) , strength (f 0) and frequency (ω) of the external periodic force on the analytical DIAWs are shown. The results of the present paper will be useful in laboratory and space plasmas. [ABSTRACT FROM AUTHOR]

Present paper studies the contribution of both the quantum effect and the dust size distribution effect on the shock wave characters. It is concluded that the quantum effect of dust particles is negligible, while the quantum effects of both electrons and ions on the shock wave of a quantum dusty plasma cannot be neglected in certain cases. It is found that the speed and the amplitude of the shock wave, considering the dust size distribution, are larger than that of the quantum dusty plasma with the average dust size of a monosized dust plasma. Furthermore, the speed and the amplitude of the shock wave increase, while the width of the shock wave decreases as the ratios of the maximum dust size to the minimum one increases. The quantum effects may affect both the amplitude and width of the shock wave, while it has no effect on the shock wave speed. The width of the shock wave increases, while its amplitude decreases as H e and H i increase. [ABSTRACT FROM AUTHOR]

The physical sense and the properties of a group screening parameters which are determined in the previous papers (Part 1 and Part 2) for single- and two-component systems is discussed in this paper. On the base of data from the mentioned papers are determined two new characteristic lengths which complete a new hierarchy system of screening lengths in plasma. It was shown that the methods developed in Part 1 and Part 2 generates results which are applicable to the strongly non-ideal gaseous and dusty plasmas, and manifest a very good agreement with the existing experimental data. [ABSTRACT FROM AUTHOR]

In this paper a new model method for describing of the electrostatic screening in single-component systems which is free of Debye-Hückel’s non-physical properties is presented. The method is appropriate for the determination of screening parameters in the case of the systems of higher non-ideality degree. The obtained screening characteristics are presented in a simple analytic form. The presented results make basic elements of a method for determination of screening characteristics in dense two-component plasmas, which are discussed in following papers. [ABSTRACT FROM AUTHOR]

A multi-ion dusty plasma containing hot isothermal electrons, ions (both positive and negative ones), extremely and negatively charged dust grains and its corresponding dust negative ion acoustic waves are studied by using the reductive perturbation method in this paper. It is noted that they can be determined by parameters of the dust size distribution and the number densities of the ion and electrons. [ABSTRACT FROM AUTHOR]

We consider the dust charging processes in protoplanetary disks. It is shown that in the atmosphere of a disk, grains can acquire anomalously high positive charges, which can lead to their destruction as a result of the Coulomb explosion. The charging is due to the combined effect of radiation from a protostar and of electron and ion currents from the surrounding plasma. For typical protoplanetary disk conditions, such a process turns out to be effective both for porous dust grains of micron sizes and for submicron crystalline grains. Critical charges that are necessary for the destruction of dust grains and the charges acquired by the particles are found for their different sizes and various parameters of the dusty plasmas. Critical grain sizes as functions of the distance to the host star are calculated. It is shown that the Coulomb explosion leads to the appearance of a cascade of crushing of large dust grains. The character of the dependence of crushing conditions on the dust particle radius can lead to the formation of a bimodal grain size distribution in some areas of protoplanetary disks. One fraction corresponds to large particles that are not subject to destruction and the other, to small particles of submicron size. [ABSTRACT FROM AUTHOR]

Dusty plasma research is one of the most extensively developed areas of modern plasma physics. In spite of the large number of papers devoted to determining the electric potential of dust grains in gas discharge plasmas, this problem is still far from being resolved completely. In this paper, the behavior of the floating electric potential of a macroparticle in an electron beam-plasma system is studied in the framework of the orbit motion limited model taking into account secondary electron emission. [ABSTRACT FROM AUTHOR]

This paper investigates time-fractional (2+1)-dimensional new coupled Zakharov-Kuznetsov system for the invariance properties, conservation laws, and soliton solutions. Lie infinitesimal symmetries and corresponding similarity reductions are carried out with Riemann-Liouville fractional derivative. The similarity reductions yield the reduced (1+1)-dimensional nonlinear fractional partial differential equations having extended Erde´lyi-Kober fractional differential operator. The new conservation theorem is used to determine the conserved vectors. The fractional complex transformation converts the given system into ordinary differential equations. Further more, the solutions of these ordinary differential equations are appeared in terms of bright, dark, and singular solitons. The graphical representation of solutions is presented to show the effect of fractional order α on the wave profile as well as on their velocity. [ABSTRACT FROM AUTHOR]

A theoretical investigation of the phase-mixing phenomenon of Langmuir oscillations (LOs) in a multi-component dusty plasma is presented. The plasma under study is a four-component plasma consisting of electrons, positrons, singly ionised positive ions and positive (or negative) polarity dust grains. The massive dust grains are assumed to form a fixed charge neutralising background, while the electrons, positrons and ions are considered to take part in the wave dynamics. A simple perturbative analysis of the governing fluid-Maxwell's equations leads us to an approximate relation for phase-mixing time of LOs, improving some earlier existing results. It is revealed that even though the dust grains remain motionless in the background, they still have significant impact on the phase-mixing process of LOs in such plasmas. It is found that the nature of the charge on the dust grains and the equilibrium dust density profoundly affect the phase-mixing time. The results of this investigation is expected to have relevance in space-plasma environments. [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]

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]

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]

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]

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]

Dusty plasma crystals are commonly considered as spatially homogeneous structures with equal values of their structural and thermodynamic parameters in various regions of the system. Inhomogeneity of the interparticle distance, the amplitude of thermal particle oscillations, the Lindemann parameter, and the coupling parameter is shown to arise even in a system of particles with a simplified interaction model including a screened Coulomb potential and a parabolic trap. The kinetic energy distribution for particles in an inhomogeneous dusty plasma monolayer is investigated: it is shown that the mean kinetic energy of particles in the central part of the structure can differ significantly from the mean kinetic energy of particles on its periphery due to the inhomogeneity of structural parameters. The detected effects are verified using analytical methods and numerical simulations and by comparison with a dusty plasma experiment in a dc glow discharge. The results obtained are of great importance for investigating finite systems of like charges in a trap and studying the mechanism of phase transitions in dusty plasma systems. [ABSTRACT FROM AUTHOR]

Analytical solitary wave solution of the dust ion acoustic waves is studied due to the damped forced modified Korteweg-de Vries equation in an unmagnetized collisional dusty plasma consisting of negatively charged dust grain, positively charged ions, q-nonextensive electrons, and neutral particles in the presence of external periodic force. Using reductive perturbation technique, the damped forced modified Korteweg-de Vries equation is obtained for the dust ion acoustic waves. Momentum consevation law is used to obtain the dust ion acoustic solitary wave solutions in the framework of the damped forced modified Korteweg-de Vries equation. The effects of different physical parameters such as entropic index, dust ion collisional frequency, strength and frequency of the external periodic force, speed of the traveling wave and the parameter which is the ratio between the unperturbed densities of the dust ions and electrons are investigated on the analytical solution of the dust ion acoustic waves. It is observed that those parameters have significant effects on the structures of the damped forced dust ion acoustic solitary waves. The results of the present paper may have applications in laboratory and space plasma environments. [ABSTRACT FROM AUTHOR]

High rate sampling detectors measuring the potential difference between the main body and boom antennas of interplanetary spacecraft have been shown to be efficient means to measure the voltage pulses induced by nano dust impacts on the spacecraft body itself (see Meyer-Vernet et al. in Sol. Phys. 256:463, ). However, rough estimates of the free charge liberated in post impact expanding plasma cloud indicate that the cloud's own internal electrostatic field is too weak to account for measured pulses as the ones from the TDS instrument on the STEREO spacecraft frequently exceeding 0.1 V/m. In this paper we argue that the detected pulses are not a direct measure of the potential structure of the plasma cloud, but are rather the consequence of a transitional interruption of the photoelectron return current towards the portion of the antenna located within the expanding cloud. [ABSTRACT FROM AUTHOR]

Heterogeneous catalysis is of paramount importance in many areas of gas conversion and processing in chemical engineering industries. In porous pellets, the catalytic reactions may be affected by diffusional limitations such that the global rate can be different from the intrinsic reaction rate. In the literature, a number of multicomponent diffusion flux closures have been applied to characterize the diffusion process within different units in chemical process plants. The main purpose of this paper is to outline the derivation of the different diffusion flux models: the rigorous Maxwell-Stefan and dusty gas models, and the simpler Wilke and Wilke-Bosanquet models. Usually the diffusion fluxes are derived and presented with respect to the molar average velocity definition. In this study, also the diffusion flux closures with respect to the mass average velocity definition is outlined. Thus, if the temperature equation and the momentum equation are used in the pellet model, a consistently closed set of pellet equations is obtained on mass basis holding only the mass average velocity. On the other hand, for the closed set of pellet equations on molar basis, the component balances hold the molar averaged velocity whereas the temperature and momentum equations hold the mass average velocity due to the physical laws applied deriving these fundamental balances. Nevertheless, the Maxwell-Stefan and dusty gas models are manipulated and put on the convenient Fickian form. The second purpose of this article is the evaluation of the diffusion flux closures derived. For this purpose, a transient model is developed to describe the evolution of the species composition, pressure, velocity, temperature, total concentration, and fluxes within a spherical pellet. The catalyst problem has been simulated for the methanol dehydration process producing dimethyl ether (DME), with computed efficiency factor values in the range 0.06-0.6 for pellet pore diameters of 0.1-100 nm. Identical results are expected for the mole and mass based pellet equations. However, deviations are obtained in the component fractions comparing the mass and mole based pellet model formulations where the mass fluxes were described according to the Wilke and Wilke-Bosanquet models. On the other hand, the rigorous Maxwell-Stefan and dusty gas models gave identical results. [ABSTRACT FROM AUTHOR]

Results from optical photometric observations of the pre-main sequence star GM Cep are reported in the paper. The star is located in the field of the young open cluster Trumpler 37-a region of active star formation. GM Cep shows a large amplitude rapid variability interpreted as a possible outburst from EXor type in previous studies. Our data from BVRI CCD photometric observations of the star are collected from June 2008 to February 2011 in Rozhen observatory (Bulgaria) and Skinakas observatory (Crete, Greece). A sequence of sixteen comparison stars in the field of GM Cep was calibrated in the BVRI bands. Our photometric data for a 2.5 years period show a high amplitude variations ( $\Delta V \sim2\mbox{$.\!\!^{\mathrm{m}}$}3$) and two deep minimums in brightness are observed. The analysis of collected multicolor photometric data shows the typical of UX Ori variables a color reversal during the minimums in brightness. On the other hand, high amplitude rapid variations in brightness typical for the Classical T Tauri stars also present on the light curve of GM Cep. Comparing our results with results published in the literature, we conclude that changes in brightness are caused by superposition of both: (1) magnetically channeled accretion from the circumstellar disk, and (2) occultation from circumstellar clouds of dust or from features of a circumstellar disk. [ABSTRACT FROM AUTHOR]

The paper considers the basis of the approach used to study the response of dusty plasma clusters of various compositions in confining fields of various configurations. The problem statement and analysis are based on the concepts of physical mesomechanics. For an external confining field an electric field and gravity force combination is used. Calculations were performed in the framework of molecular dynamics. The interparticle interaction is described by the Debye-Hiickel pair isotropic potential. The charge of dust particles is calculated using the orbital motion limited theory. The parameters of the field configuration are determined with the use of experimental data. Calculations of both the structure of a formed dusty plasma cluster and the characteristic spacings of dust particles agree well with available experimental data. The emphasis in the paper is on the dependence of the structure and shape of dusty plasma clusters on the number of dust particles in confining fields of varying anisotropy. It is shown that in the crystalline state, dust particles form a Coulomb ball with a shell structure in an isotropic external field. It is pointed out that dusty plasma clusters can transform from the bulk to plane state. In the crystalline state, both plane and bulk dusty plasma clusters have a shell structure; however in the anisotropic state, their structure becomes more complex and split. [Copyright &y& Elsevier]

In this paper, the characteristics of the dust acoustic solitary waves in dusty plasmas are studied. The distribution of ions is nonthermal, and the nonthermal parameter is treated as a variable. The pseudo-potential method has been used to investigate the possibility of soliton formation. We show that for some values of the nonthermal parameter there is no soliton. [ABSTRACT FROM AUTHOR]

A new model method for describing of the electrostatic screening in two-component systems (electron-ion plasmas, dusty plasmas, electrolytes, etc) is developed. The method is applicable to the systems of higher non-ideality degree. The expressions for all the screening parameters introduced in the previous paper (Part 1) of this work, as well as for an additional parameter characteristic for multi-component systems, are obtained. All these parameters are presented in a simple analytic form suitable for operative laboratory usage, especially for theoretical interpretation of experimental data. [ABSTRACT FROM AUTHOR]

The paper presents an introductory review of the basic physical processes in dusty plasmas. The topics to be addressed are dust charging, forces acting on dust grains, interaction between dust grains, and dust–plasma structures. © 2005 Pleiades Publishing, Inc. [ABSTRACT FROM AUTHOR]

The paper deals with the results of experimental investigation of the dynamic behavior of macroparticles charged by way of photoemission, under conditions of microgravity. The experimental data have been obtained for bronze particles subjected to solar radiation in a buffer gas at a pressure of 40 Torr (Mir space station). Different procedures for determining the transport properties of macroparticles by analyzing video records of experiments are treated. The velocity distribution, the temperature, the charge, the friction coefficient, and the dust particle diffusion coefficients are found. The results of comparing the experimental and theoretical estimates demonstrate that the dynamic behavior of macroparticles under the conditions of investigations are defined by the process of their ambipolar diffusion. [ABSTRACT FROM AUTHOR]

The dispersion relation and Landau damping rate of dust-acoustic waves (DAWs) are studied by the incorporation of Poison–Vlasov model of the kinetic theory of plasmas. The real and imaginary frequencies of DAWs are obtained in a three-component plasma i.e., electrons, ions and dust grains. The electrons are taken as hybrid non-thermal Vasyliunas–Cairns distributed and in limiting cases as kappa and Cairns distributed as well, while the ions and dust are kept Maxwellian. The findings reveal that the simultaneous presence of two non-thermality parameters (i.e., α and κ ) have a remarkable impact on the dispersion and damping rates of DAWs as compared to the sole presence of any non-thermality parameter and also in the case of thermal electrons. It is also presented that the real and imaginary frequencies of DAWs are significantly influenced by the other important parameters, such as electron to ion temperature and density ratios. This work has notable significance in the understanding of important constituents of space plasmas i.e., thermal and non-thermal dusty plasmas in various environments of space plasmas, where the mixed particle distributions are observed. [ABSTRACT FROM AUTHOR]

The dispersion relation and instability of dust acoustic waves (DAWs) in an unmagnetized dusty plasma with two different temperatures for ions, two different temperatures for electrons, and dust charge fluctuations are investigated. Ions and electrons are assumed to be Maxwellian distributed. The orbital limited motion theory (OLM) is used to derive dust charge fluctuations. The conditions for the instability are found to be significantly modified by the effects of two different temperatures of ions (electrons), dust charge fluctuations, density ratio of ions and density ratio of electrons. Furthermore, it is observed that there is only damping rate in such dusty plasma. [ABSTRACT FROM AUTHOR]

In this article, we studied the approximate analytical soliton solution of dust acoustic waves in the framework of damped Korteg–De Vries (DKdV) equation. Using the reductive perturbation technique, the evolution equation with additional damping term is derived from a collisional dusty plasma model. As the DKdV equation is not integrable, a numerical solution to the DKdV equation is found and is obtained by using the Adomian decomposition method, taking the solution of the standard KdV equation as an initial approximation. The comparison between the current solution with the existing solution proposed earlier by other authors for smaller values of the damping parameter shows a very good agreement between these two. A significant difference in the solution is observed for the higher value of collision frequency. The effect of some relevant plasma parameters on the proposed solution is also analyzed. [ABSTRACT FROM AUTHOR]

This article presents bi-soliton, soliton, and shock solutions for the ion-acoustic wave (IAW) propagating in an unmagnetized nonplanar dusty plasma containing cold ions, neutral particles, and the electrons obeying κ -deformed Kaniadakis distribution. Applying the reductive perturbation method (RPM) to the basic equations, the nonplanar KdV–Burger (KdVB) equation is derived. It is found that there is a parametric domain for which the nonlinear coefficient vanishes, and naturally, the infinite divergence of the amplitude of the soliton arises. To describe the dynamic features of the wave quantities at or near the parametric domain, the nonplanar modified KdV–Burger (mKdVB) equation is constructed. The dissipation effect in the viscous plasma is expressed in the current study by a Burgers term, and the weighted residual method (WRM) is used to produce a solitary-type progressive wave solution for very small values of the Burgers term. Hirota's bilinear formalism is employed for finding the multi-soliton solutions for the nonplanar mKdV system. However, the strong dissipation may cause the origination of a shock solution. An approximate analytical solution is also explored by means of WRM, through which the evolution of shock waves is determined. Finally, under the variation of various physical parameters, the evolution of different types of wave quantities is numerically examined. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) thermal conductivity of strongly coupled dusty plasmas, taking into account the polarization effect of dust particles, has been investigated through homogenous nonequilibrium molecular dynamics (HNEMD) simulations. Thermal conductivity (λ), in the limit of varying polarization values, is reported over a appropriate domain of plasma states (Γ, κ), coupling (dipole–dipole) factor (Γd) and constant external force field (F*). New results of polarized λ show that the effect of polarization definitely decreases the λ at low-intermediate to large Γ where it was earlier shown to have high value of λ without considering polarization effects. The obtained results for polarized λ decrease with increasing system size (N) and Coulomb coupling (Γ) at varying polarization values (Γd) but within statistical limits, however, polarized λ becomes nearly constant at higher N. The simple temperature scaling law has been checked for variations of normalized (Einstein) thermal conductivity with polarization effects. The current HNEMD outcomes under varying polarization values and constant force (external) field strength are reasonable well matched with earlier known simulation data of equilibrium, nonequilibrium molecular dynamics simulations and experimental data. It has been revealed that the present HNEMD simulations extended the range of polarization values up to 1 ≤ Γd ≤ 150 in order to maintain the range of linearity at F* (≡ 0.2) and to illuminate the nature of polarized system of 2D strongly coupled dusty plasmas. [ABSTRACT FROM AUTHOR]

Nonlinear dust acoustic solitary waves (DASWs) in an unmagnetized dusty plasma with a negatively charged dust fluid are studied in bounded two-dimensional (2D) cylindrical geometry. The dusty plasma was assumed to have electrons with Boltzmann distribution and ions with vortex-like distribution. Transverse perturbation was observed in such dusty plasma. By using the reductive perturbation method along with new space-time stretched coordinates, modified Korteweg–de Vries (K–dV) equation was derived for cylindrical geometry. Particularly, exact solution for the modified K–dV equation in 2D cylindrical geometry was obtained. The solution was investigated for different physical parameters of the plasma. It has been found that the trapped ions have significant effect on the properties of nonlinear waves (small but finite amplitude and width) in cylindrical geometry. The results also show that only compressive solitary waves can be formed in this system. According to the results, the properties of the DASWs in 2D cylindrical geometry differ from 1D cylindrical geometry. Furthermore, unlike the planar modified K–dV equation, in cylindrical modified K–dV equation, solitary structures are slightly deformed in time. The results of present investigation may help to understand the nature of DA solitary structures where dust along with non-Maxwellian ions exists. Such structures can be found in different regions of space and astrophysics mediums. [ABSTRACT FROM AUTHOR]

We report the first experimental observations of a single-mode Kelvin-Helmholtz instability in a flowing dusty plasma in which the flow is compressible in nature. The experiments are performed in an inverted Π -shaped dusty plasma experimental device in a DC glow discharge Argon plasma environment. A gas pulse valve is installed in the experimental chamber to initiate directional motion to a particular dust layer. The shear generated at the interface of the moving and stationary layers leads to the excitation of the Kelvin-Helmholtz instability giving rise to a vortex structure at the interface. The growth rate of the instability is seen to decrease with an increase in the gas flow velocity in the valve and the concomitant increase in the compressibility of the dust flow. The shear velocity is further increased by making the stationary layer to flow in an opposite direction. The magnitude of the vorticity is seen to become stronger while the vortex becomes smaller with such an increase of the shear velocity. A molecular dynamics simulation provides good theoretical support to the experimental findings. [ABSTRACT FROM AUTHOR]

One of the remarkable properties of Polar Mesosphere Summer Echoes (PMSE) is their occurrence in the form of distinct multiple layers (double- and tri-layers). Using the PMSE observations of E-ISCAT VHF radar, for the first time, we present a combination of heating with multiple layers. Our main focus is to compare the heating effects between the mono-, double-, and tri-layers. Our results show that, as compare to mono-layer, PMSE is greatly affected by HF heating in multiple layers. As a result, the modulated characteristics (e.g., PMSE intensity reduction, recovery, and overshoot) produced in multiple layers are greater than those in mono-layer. Inside multiple layers, the PMSE heating decreases with increasing altitude. Due to heating, the enhancement produced in electron temperature is estimated which is also greater in multiple layers than those in mono-layer. The considerable increase in electron temperature may be one of the possible reasons for the strong heating effects in multiple layers. In addition, we show the dependency of the PMSE heating on the HF pump parameters (effective radiated power (ERP), polarization, frequency, and heating cycle time). It is found that in all layers, the PMSE heating increases with increasing ERP. X-mode and O-mode polarizations produce strong heating in mono-layer and in multiple layers, respectively. We found no significant effect of Heater frequency on PMSE heating. The heating cycle time is the sum of Heater on and off times. In both, mono- and multiple layers, the increasing Heater on time does not greatly affect the PMSE heating, on the other hand, the increasing Heater off time significantly increases the PMSE overshoot effect. [ABSTRACT FROM AUTHOR]

Dielectric-barrier-discharge (DBD) plasma jets provide viable state-of-the-art nonthermal processes for a wide range of nanomaterials including particle transport and deposition. We report the interaction of argon and helium plasma jets with the particle aerosol, produced by ns laser ablation of a silver target and subsequently their transport for deposition on a distant substrate. The nanofeatures and functionality of the nanoparticles, entrained and deposited with the two plasma jets were compared using high-resolution electron microscopy, helium ion microscopy, scanning electron microscopy, ultraviolet–visible spectroscopy, and in terms of the SERS effect. The plasma jet facilitates the transport of the particle aerosol under the upshot of plasma ionic wind, caused by the high electric field in the plasma. Compared to the helium plasma jet, the argon plasma jet leads to a relatively large particle deposition and promotes the formation of aggregates. The helium plasma jet enabled the deposition of spatially well dispersed particles. In both cases, the deposited particle was crystalline and plasmonic active. The plasma-driven altered morphology, expedient particle transport, and formation of agglomerates or spatially well dispersed particles are explained in plasma-induced ionic-wind, and dusty plasma framework. The findings are novel and interesting from the perspective of plasma–surface deposition, surface nanoengineering, and nanomaterial processing for applications in sensing, catalysis, surgical tools, futuristic coating technology, and heat-sensible biological activities. [ABSTRACT FROM AUTHOR]

Theoretical investigation of dust acoustic shock waves (DAShWs) in an unmagnetized collisionless multicomponent dusty plasma of the Jupiter's atmosphere featuring kappa distributed ions, electrons, solar wind electrons and their interaction with the positive dust particles and the streaming protons originating from the solar wind was made. In the framework of reductive perturbation method, the KdV–Burgers equation has been derived to explain the dynamics of the dust acoustic shock waves. The evolution of the oscillatory shock waves also was illustrated. The effects of various physical parameters namely, the temperature ratio, fluid viscosity, superthermality and density of charged particles were analyses. The combined impact of these parameters greatly influence the characteristics of the shock waves. The present investigation may be useful to understand the underlying properties of various types of nonlinear structures and to explore the existence of dust acoustic shock waves in the Jupiter's atmosphere. [ABSTRACT FROM AUTHOR]

A dusty plasma consisting of ions following the Cairns–Tsallis (C–T) distribution, Boltzmann electrons, and negatively charged dust as a fluid is considered in the presence of a polarization force to investigate higher order dust acoustic (DA) nonlinear structures. Using the reductive perturbation technique, the Burgers and higher order Burgers equations are derived and the Tanh method is applied to determine the solutions of the Burgers equations. Based on the solutions to these nonlinear equations, the influence of various parameters on the features of the dust acoustic shocks and dressed shocks has been studied. The dynamics of DA shocks with the contribution of higher order corrections has been analysed to see the formation of dressed shocks. [ABSTRACT FROM AUTHOR]

The mechanism of modulational interaction of various wave modes in the meteoroid tails is described. Modulational instability of different oscillation modes can lead to the appearance of a number of effects observable in the meteoroid tails, such as the electrophonic noises. In particular, the modulational instability of the electromagnetic waves from the meteoroid shock wave related to the dust-acoustic mode, along with the modulational instability of the lower hybrid and Langmuir waves, can cause these effects. Waves that subsequently transform into an acoustic wave reaching the Earth's surface can be generated in the first case. Magnetic fields with a magnitude comparable to that of the magnetic fields experimentally detected by means of magnetometers can appear in the latter two cases. Transverse electromagnetic oscillations that can be perceived as electrophonic noises heard simultaneously with the meteoroid passage when they reach the Earth's surface can propagate as well. We analyze the influence of meteor flashes on parameters of the dusty plasma of the meteoroid tails depending on the altitude of the meteor-body passage. Characteristic concentrations of dust particles in the meteoroid tails during flashes as a function of altitude are estimated. Using the example of modulational instability of electromagnetic waves related to the dust-acoustic mode, we demonstrate how increased concentration of dust particles during flashes influences the growth rate of the instability and conditions of its development. [ABSTRACT FROM AUTHOR]

The thermodynamic stability of a multicomponent plasma is studied on the basis of the Ornstein–Zernike integral equations for a multicomponent fluid. A transition is made to the one-component Ornstein–Zernike equation for the most non-ideal subsystem for a plasma with any number of components under the conditions of applicability of the Debye approximation for direct correlation functions for all plasma components, except for the most non-ideal subsystem. It is shown that all pair correlation functions, charge–charge and number–number structure factors remain positive for all argument values in the entire studied range of the non-ideality parameter of the most non-ideal subsystem. The conditions for the violation of the thermodynamic stability of a three-component dusty plasma are studied for different signs of the charge of dust particles and their different number density. [ABSTRACT FROM AUTHOR]

A brief review of recent studies on dusty plasma above the lunar surface at the Space Research Institute, Russian Academy of Sciences is presented. The research is related to the future Luna-25 and Luna-27 missions, which will study the properties of dust and dusty plasma above the lunar surface. The problems of formation of dusty plasma over the illuminated part of the Moon, in the region of the lunar terminator, the influence of magnetic fields on the circumlunar dusty plasma, and the influence on the results of measurements of the spacecraft landing module are considered. Unsolved problems concerning the study of the near-lunar dusty plasma are formulated. [ABSTRACT FROM AUTHOR]

A self-consistent numerical model is presented in which a self-consistent spatial distribution of plasma potential is calculated near isolated dust particles whose shape represents an ellipsoid of revolution. In this model, self-consistent electric plasma potential is calculated with the help of Legendre polynomial expansion of a spatial space charge, while ion trajectories are calculated in the mean field approximation. This article demonstrates a large-scale study of self-consistent distributions of space charge density and plasma potential in the presence of an external electric field. The dependencies of "the ion cloud–dust particle" system on various dusty plasma parameters are calculated. The parameters are dust particles shapes and sizes, the external electrostatic field strength, and the ion mean free path. The dependencies of the dipole moment, wake local maximum, and position of the wake local maximum on these parameters are reduced to a simple analytical expression. [ABSTRACT FROM AUTHOR]

A concise overview of the vibrational model of heat transfer in simple fluids with soft pairwise interactions is presented. The model is applied to evaluate the thermal conductivity coefficient of the strongly coupled Yukawa fluid, which often serves as a simplest model of a real liquid-like dusty (complex) plasma. A reasonable agreement with the available data from molecular dynamics numerical simulations is observed. Universality of the properly reduced thermal conductivity coefficient with respect to the effective coupling parameter is examined. Relations between the vibrational model and the excess entropy scaling of the thermal conductivity coefficient are discussed. [ABSTRACT FROM AUTHOR]

Under conditions of glow discharge in the strong magnetic field, three-dimensional dust structures were created in the He, Ne, and Ar working gases in three types of dust traps (in standing stratum, in the region of current channel narrowing, and in the region of nonuniform magnetic field). These structures are stable in the fields of the order of 2 T. In all traps, the rotation dynamics have been studied of horizontal (perpendicular to the magnetic field) cross sections of dust structures, their angular velocities has been measured, and the nonuniform angular velocity distributions in the dust structure volumes have been measured. For the first time, for the trap in the region of current channel narrowing, the data are presented in the range of magnetic inductions of up to 2.5 T. Such magnetic fields correspond to the Ne+ ion magnetization parameter of approximately 2 and the ion cyclotron radius comparable to the shielding distance. In the fields higher than 1.5 T, the angular velocity of the structure rotation increased to 50 s–1, which is a record-breaking fast rotation of dusty plasma. For each of the traps under study, the geometrical features of the dust structures are described. [ABSTRACT FROM AUTHOR]

The present work develops a theoretical procedure for obtaining transport coefficients of Yukawa systems from density fluctuations. The dynamics of Yukawa systems are described in the framework of the generalized hydrodynamic (GH) model that incorporates strong coupling and visco-elastic memory effects by using an exponentially decaying memory function in time. A hydrodynamic matrix for such a system is exactly derived and then used to obtain an analytic expression for the density autocorrelation function (DAF)—a marker of the time dynamics of density fluctuations. The present approach is validated against a DAF obtained from numerical data of Molecular Dynamics (MD) simulations of a dusty plasma system that is a practical example of a Yukawa system. The MD results and analytic expressions derived from the model equations are then used to obtain various transport coefficients and the latter are compared with values available in the literature from other models. The influence of strong coupling and visco-elastic effects on the transport parameters are discussed. Finally, the utility of our calculations for obtaining reliable estimates of transport coefficients from experimentally determined DAF is pointed out. [ABSTRACT FROM AUTHOR]

Equilibrium molecular dynamics (EMD) simulations have been executed to investigate the parallel (D║) and perpendicular (D┴) diffusion coefficients for three-dimensional (3D) strongly coupled (SC) electrorheological complex (dusty) plasmas (ERCPs). The effects of uniaxial (z-axis) AC electric field (MT) on dust grains have been investigated along with various combinations of plasma parameters (Γ, κ). The new outcomes obtained by mean squared displacement of Einstein relation show diffusion coefficients for low-intermediate to high plasma couplings (Γ) for varying MT. The D║ and D┴ at MT = 0.01 agree well with earlier available data obtained from the Green–Kubo and Einstein relation for 3D SC-Yukawa systems. The simulation data show that D║ increased with an increase in moderate MT strength and that D┴ decreased for the intermediate to large MT strength. Both (D║ and D┴) remained nearly constant for low MT values. The investigations show that the current EMD scheme is more efficient for nonideal gas-like, liquid-like, and solid-like states of SC-ERCPs. It has been demonstrated that present simulation outcomes extended the MT range up to 0.01 ≤ MT ≤ 10 to understand the diffusive and rheological behaviors of dusty plasma systems. [ABSTRACT FROM AUTHOR]

In recent years nanoparticles have become key technological products, e.g., as coatings with tunable optical gap in third generation solar cells, as nanocrystals for photonic applications, and as pharmaceutical nanocarriers. In particle sources, that use reactive, nanodusty plasmas, a high dust density changes the properties of the dusty plasma compared to a dust free plasma considerably, as electron depletion leads to a reduced number of free electrons. This is called the Havnes effect and was central for the understanding of the famous spokes in Saturns rings. We see here, that it is also important for technological applications. Using self excited dust density waves (DDW) as a diagnostic tool, we completely characterize an argon discharge with embedded amorphous hydrocarbon nanoparticles of different size and density. The results show, that electron depletion governs the charge of dust grains, while the size of the particles has only a weak influence. The ion density and electric potential profile are almost independent of both, dust size as well as dust density. This suggests, that the rf generated plasma and the dust cloud seem to coexist and coupling of both is weak. Plasma created nanoparticles have become a valuable technological product in many fields, from solar cells to pharmaceutical applications. The authors use self-excited dust density waves to study the properties of an electron depleted plasma containing nanodust particles, and show that a variation of particle size and concentration has only minor effects on the ion generation and density. [ABSTRACT FROM AUTHOR]