Charged Dust Particles Research Articles

Nonlinear ion‐acoustic waves in magnetized plasmas in presence of energetic electrons and positively charged dust

AbstractA theoretical investigation has been carried out for exploring different features of ion‐acoustic solitary and shock waves in a three‐component magnetized plasma containing a mixture of thermal and nonthermal (energetic) inertialess electrons, warm inertial ions, and positively charged stationary dust particles. The standard Korteweg‐de Vries (Burgers) equation has been derived by employing the reductive perturbation method, and its solitary (shock) wave solution has been derived and examined analytically as well as numerically. The latter exhibits characteristic properties (amplitude, width, speed, and polarity) of the ion‐acoustic solitary and shock waves. It has been shown that the ion‐acoustic solitary and shock waves are significantly modified by different plasma parameters (viz. parameter measuring the ratio of dust charge density to ion charge density, parameter measuring the fraction of energetic electrons, parameter measuring ion or electron temperature, and the external magnetic field). The present investigation may help in understanding the physics of various nonlinear phenomena formed in many space plasma systems, (viz. earth's mesosphere, solar wind, and cometary tails) and laboratory devices (laboratory experiments of Samarian et al., Phys. rev. E. 64, 056407 [2001] and of Fortov et al., New J. Physics 5, 102 [2003]).

Test charge driven response of a dusty plasma with polarization force

By using the framework of kinetic model, the test charge driven response of a dusty plasma is evaluated in the presence of polarization force. The plasma containing electrons, singly ionized positive ions, and highly charged negative dust particulates is known as a dusty plasma, which can be perturbed by a test particle of charge qT moving with velocity vT along the z-axis. The polarization force purely comes from the high charging state of micron-sized dust particles, causing a deformation of shielding length due to density gradient and modifying the collective motion and particulates’ acceleration. The application of Fourier transformation technique to the set of dynamical equations may result in the shielded potential for a test charge with a modified dielectric constant. Several possibilities have been explored to evaluate the shielded potentials by imposing different conditions on the test charge speed in comparison with the thermal speeds of plasma species. It is found that the profiles of wakefield, Debye-Hückel and farfield (FF) potentials are strongly modified by the polarization force coefficient via the dust charging state and dust concentration. The present findings are useful in the study of strongly coupled dusty plasma, where micron-sized negatively charged dust grains are characterized by a high charging state.

The electrostatic wave modes and formation of dust voids in an externally magnetized cylindrical dusty plasma

Abstract A system of dusty plasma, containing negatively charged dust particles, Boltzmann distributed electrons and ions, is considered in a cylindrical set up and electrostatic wave modes have been studied in the presence of an external magnetic field. The dust particles are of two different sizes such that small grains are present in significant amount. Using Fourier transformation along temporal and azimuthal directions, linear dispersion relation is derived, which indicates the existence of two distinct wave modes for the stable case. Among the breathing and rotation modes, density profiles have been observed numerically for the rotation mode corresponding to the stable case. The density fluctuation of small grains is noticed to be more prominent than that of the big grains. In the presence of external magnetic field, large grains contribute very negligible magnitude of dust number density in those regions, where voids are generated by the small grains only. The effect of mode number on the dust density fluctuation as well as on the structure of density profile is observed. The magnetic field effect on dust void formation is also studied.

Dust-acoustic periodic travelling waves in a magnetized dusty plasma with trapped ions and nonthermal electrons in astrophysical situations: oblique excitations

Obliquely propagating three-dimensional dust-acoustic periodic travelling waves (DAPTWs) in a magnetized dusty plasma composed of negatively charged inertial dust particles, trapped ions, and nonthermal fast electrons have been undertaken. In the dusty plasma model at hand, the dynamic behaviors of DAPTWs are governed by a Schamel equation. The presence of dust acoustic solitary waves (DASWs) and DAPTWs is investigated via bifurcation analysis of the Hamiltonian system. In the nonlinear regime, the Sagdeev potential and phase portrait structures indicate the presence of small-amplitude DAPTW solutions. The influences of intrinsic physical parameters include the strength of the static magnetic field, the obliqueness of propagation, the thermal pressure of charged dust grains, the electron to dust density ratio, the trapping parameter of trapped ions, and the degree of nonthermality of fast electrons on the characteristics of DAPTWs are simulated numerically. In particular, the findings illustrate that the amplitude of DAPTWs is reduced as the numerical values of the trapping parameter are decreased. Interestingly, the theoretical simulations of numerical results can significantly highlight the physical nature of DAPTWs in astrophysical situations such as Earth’s magnetosphere, auroral region, and heliospheric environments.

Latitudinal dynamics of co-orbital charged dust in the heliosphere

In recent years, observations have found evidence for dust at higher ecliptic latitudes. Different possible explanations for these signatures have been proposed, most commonly assuming that they originate from collisions of young asteroid families. In the present work, we investigate the influence of the interplanetary magnetic field causing strong latitudinal oscillations that may affect the creation and evolution of dust at these latitudes. Using numerical simulations of a charged dust particle affected by the Lorentz force, we analyse the effect of a simplified magnetic field model specifically on the long-term evolution of the orbital plane of the dust grain. Additionally, we demonstrate the significant agreement with the results of the semi-analytical secular-resonant model we have developed for charged particles in co-orbital motion with a planet. We have found that the interplanetary magnetic field determines the three-dimensional distribution of micron-sized dust grains, causing large excursions of the orbital inclination that distribute the particles to high ecliptic latitudes. The strength of these oscillations depends in particular on the particle size and on the distance to the Sun. Farther outwards in the Solar System, the particle amplitudes are larger.

Temporal dusty plasma afterglow: A review

In complex plasmas, dust particles are charged through their interactions with the electrons and ions of the surrounding plasma. In low-temperature laboratory plasmas, dust particles most commonly acquire a negative charge. In particular, in a laboratory glow-discharge plasma, the typical charge for a micrometer-size grain generally attains a few thousands of electronic charges. Under stable discharge conditions, this large negative charge is relatively well-characterized. However, for unsteady discharge conditions, the charge can differ and even fluctuate. In particular, when the power source of the discharge is turned off, the charged species of the plasma diffuse away and recombine into neutral species: this is a temporal afterglow. When dust particles are present inside a temporal plasma afterglow, the diffusion of charged species and the plasma decay dynamics are affected. Moreover, the dust particle charges also evolve during the afterglow period. In the late afterglow, dust particles are known to keep residual charges. The value of these residual charges strongly depends on the ambipolar-to-free diffusion transition. In addition, the presence of a constant electric field, causing ions to drift through the neutral gas, has a strong influence on the final dust particle residual charges, eventually leading to large positive residual charges. In this review article, the dynamics of temporal complex plasma afterglow are discussed. Experimental and theoretical results are presented. The basics of temporal afterglow modeling are also given.

Investigating particle-particle electrostatic effects on charged lunar dust transport via discrete element modeling

NASA surface exploration missions have always seen negative effects of dust including the Apollo missions. The astronaut-witnessed unusual behavior of the dust particles that surround the vehicle after engine cutoff has the potential to have more of an influence on surface systems dust loading than the high velocity lunar rocket plume ejecta in the landing process. The levitation and transport of the fine components of regolith on lunar surface has been linked to electrostatic effects and electric field, but so far there is no accurate model considering the inter-particle electrostatic interactions, especially when the particles are charged by rocket plume or other mechanical interactions due to exploration activities. This study is proposed to investigate the dynamics of charged lunar regolith with a discrete element method (DEM) approach focusing on the inter-particle interactions and contact charge transfer. The grain dynamics is coupled with mechanical and electrical particle interactions, and both short- and long-range interactions between spherical particles are incorporated. A tribo-charging model based on instantaneous collisions between particles is adopted and validated by comparing the simulation results to existing experimental data. Sensitivity analysis is conducted to quantify the effects of initial charge, tribo-charging, and E-field on transport of lunar dust based on JSC-1 simulants with a radius of 50 μm. DEM simulations are also conducted in a near realistic lunar environment with the estimations of initial conditions that shows the difference in position and velocity distributions between charged particles and uncharged particles. The results indicate that the charged dust particles have higher dispersion of position and velocity by several orders of magnitude due to electrostatic effects. This provides a potential explanation for the phenomena of the approximately 30 s dust lofting following Apollo Lunar Module landing.

Dust particle surface potential in fusion plasma with supra-thermal electrons

By solving the current balance equations, the effect of the supra-thermal electrons on the surface potential of a negatively charged dust particle in a fusion plasma is studied based on the orbital motion limited theory. A non-Maxwellian plasma is modeled by employing a q-non-extensive velocity distribution, where a decreased q-parameter (q < 1) yields increased population of supra-thermal electrons. It is found that with the decrease in the q-parameter, the surface potentials of tungsten and carbon dust particles become more negative. When the ion temperature or ion flow velocity is increased, the dust surface potential changes non-monotonically, which is first decreasing and then increasing. For a small q-parameter, the non-monotonic variation is more pronounced and the minimum value of surface potential moves toward higher values of the ion temperature or ion flow velocity. Due to the dependence of the dust particle surface potential on the supra-thermal electrons, the increased proportion of supra-thermal electrons causes the increase in the ion drag force and the decrease in the dust particle lifetime. Here, lifetime refers to the time taken for the dust surface temperature to increase from its initial value to the sublimation temperature (for carbon) or the melting temperature (for tungsten). The decrease in lifetime caused by supra-thermal electrons is significant as the dust particle radius is increased.

Bernstein–Greene–Kruskal Ion Modes in Dusty Space Plasmas Application in Saturn’s Magnetosphere

Frequent observations of ion beams moving out from Saturn’s plasma environment hints at the generation of ion Bernstein–Greene–Kruskal (BGK) modes. As the plasma environments of Saturn and its moon Enceladus are characterized by the ubiquitous presence of massive negatively charged dust particles, the existing BGK theory for electron-ion plasma models cannot address this scenario. This manuscript develops a theoretical model for studying ion BGK modes in dusty plasmas. The analysis reveals that the presence of dust in the plasma enhances the stability of BGK modes. As the dust density increases, the effect of other parameters on stability, such as the electron temperature, becomes negligible. The model is developed by assuming that electrons and ions follow a kappa distribution, featuring a long tail trend in the superthermal component, in agreement with observations. Different scenarios with either electrons or ions obeying a Maxwell or kappa distribution function have been considered. A thorough analysis of the trapped ion distribution function considering various combinations indicates that a plasma where electrons are in thermal equilibrium and ions follow kappa distribution is the least favorable system for the generation of BGK modes.

The Complexity in Dust Charging Process With Relativistic OLM Theory

The ability to self-organization is one of the important features of complex systems that is considered in the process of dust particle charging in space plasmas. The dust grain charging process is considered by the orbital-limited motion theory (OLM) theory with help of the relativistic kappa distribution, the relativistic cross section, and the kinetic model. It is indicated that the critical areas have unique properties that show the complexity in dusty plasma systems. In these areas, the Coulomb force between dust grain and plasma particle plays an important role and has a great influence on the charging process of dust grains. It is obtained that by increasing the electron-to-ion temperature ratio in the high dust grain densities, the relativistic effects increase and the electric potential of dust grain decreases. Moreover, it is indicated that by moving away from thermodynamic equilibrium (Maxwellian), the system tends to form multicomponent plasma more. As another result, the electric potential of the dust grain is much more affected by the nonextensive degree of the electron than the ion. Finally, it is observed that with the increase of dust grain density, the transition from dust in plasma to dusty plasma occurs and multicomponent plasma is formed.

Structural properties of a chain of dust particles in a field of external forces.

This paper presents a numerical study of the structural parameters of a one-dimensional chain of three dust particles levitating in the near-electrode layer of an rf discharge or in the stratum of a dc discharge. The model considers the motion of dust particles under the action of gravity, external electric field, the Coulomb repulsion, and the electrostatic force from the space charge surrounding the dust particles. Particular attention is paid to the effect of plasma polarization around dust particles and the wake formation under the action of the external electric field. Calculations showed that the charge of the first dust particle in the chain and the total charge of the entire chain, as well as the length of the chain, grow linearly with the external electric field strength. Obtained data are in qualitative agreement with the experimental and numerical data presented in the literature. It was shown that for a certain large value of the external electric field, the charge of the third dust particle is the smallest of all the particles in the chain. It was found that with an increase in the mean value of the external electric field, the chain of dust particles is displaced as a whole in the direction opposite to the action of the electrostatic force on them.

Fabrication of a carbon/polytetrafluoroethylene nanoparticle-coated antistatic bag filter using air-assisted electrospraying

Fabric bag filters have been widely used as air pollution control equipment owing to their high collection efficiency. However, the low efficiency of the fabric filtration method against fine dust and the high operating cost owing to the high-pressure drop have restricted its effective application. In addition, the filling of the fabric of bag filters by the passage of gas and deposited charged dust particles results in the generation of a static electricity that can cause a fire. To solve this problem, this study aimed to develop an antistatic filter by electrospraying carbon nanoparticles. The surface properties and conductivity of the antistatic filter as a function of the mixing ratio were compared, and the particle filtration performance as a function of the coating type was confirmed by evaluating the filter filtration performance. The results revealed that among the samples that exhibited conductivity, the sample with a mixing ratio of 1:1 exhibited the highest resistance value and best hydrophobicity. In addition, the filter performance evaluation revealed that the coated filter exhibited enhanced filtration performance compared to the uncoated filter at all particle ranges.

Dust particle charging process in a radio frequency sheath of plasma containing kappa distribution electrons

Based on self-consistent modelling of the radio-frequency sheath parameters, such as the ion and electron densities and the ion velocity, the dust particle charging process in an RF sheath is investigated by employing the kappa$(\kappa )$distribution for the electrons. It is shown that the charge number of the dust particle decreases near the sheath–wall interface while it shows the opposite tendency near the plasma-sheath edge, as the$\kappa$value is decreased. The fluctuation of the dust particle charge modified by the$\kappa$value depends on the dust particle radius. With an increases in the$\kappa$value, the fluctuation of the dust particle charge has a slight increase for a small dust particle, and it shows a significant increase for a large dust particle. In addition, as the$\kappa$value is decreased, the charge number of the dust particle obtained from the time-averaged plasma parameters deviates from the results obtained from the instantaneous plasma parameters. Moreover, a smaller deviation can be found for a large dust particle under the same$\kappa$value conditions.

Chaotic dynamics of small-sized charged Yukawa dust clusters.

In a recent work [Maity et al., Phys. Rev. E 102(2), 023213 (2020)] the equilibrium of a cluster of charged dust particles mutually interacting with screened Coulomb force and radially confined by an externally applied electric field in a two-dimensional configuration was studied. It was shown that the particles arranged themselves on discrete radial rings forming a lattice structure. In some cases with a specific number of particles, no static equilibrium was observed. Instead, angular rotation of particles positioned at various rings was observed. In a two-ringed structure, it was shown that the direction of rotation of the particles positioned in different rings was opposite. The direction of rotation was also observed to change apparently at random time intervals. A detailed characterization of the dynamics of small-sized Yukawa clusters, with a varying number of particles and different strengths of the confining force, has been carried out. The correlation dimension and the largest Lyapunov index for the dynamical state have been evaluated to demonstrate that the dynamics is chaotic. This is interesting considering that the charged microparticles have many applications in a variety of industrial processes.

Rectification experiments and 3D simulations in a dusty plasma ratchet

Realizing the control of charged dust particles in a plasma environment has important scientific significance and application prospects. This paper realizes the rectification of dust particles in RF glow discharge plasma by designing a dusty plasma ratchet experiment. The direction of the particle flow can be controlled by adjusting the discharge power and gas pressure. To reveal the rectification mechanism of dust particles, this paper reconstructs a three-dimensional distribution of plasma parameters in the ratchet channel, analyzes the dust particle dynamics, and performs Langevin simulation. Numerical simulations can quantitatively reproduce the rectification phenomena of particles. Results show that the non-equilibrium ion drag force along the ratchet channel drives the charged particles to form a directional motion. Experimental and simulation results provide an experimental support and model basis for the profound study of the control of charged dust particles and energy conversion in plasma.

Dust Acoustic Dromions in a Magnetized, Five-Component Cometary Plasma

A study of the characteristics of dust acoustic dromions (DADs), described by the Davey–Stewartson-I (DS-I) equations, in a five-component cometary plasma has been carried out, the five components being negatively charged dust particles, superthermal electrons (hotter solar and colder cometary electrons), and positively charged hydrogen and oxygen ions. It is found that the parametric region for the existence of dromions is influenced by the superthermality of both ions and electrons. The effects of various physical parameters, such as the superthermality, strength of the magnetic field, and concentrations of hydrogen and oxygen ions and cometary electrons on the propagation of the DADs, have been studied. The results of the present investigation could be useful for understanding some of the nonlinear features of localized electrostatic disturbances in a cometary environment. The study also proves that dromions can propagate in these plasmas.

Study of the Ground Level Enhancements effect on atmospheric electric properties and mineral dust particle charging

The effect of Ground Level Enhancements (GLEs) on the atmospheric and dust particles electrical properties is studied. It has been found that in the case of fair weather conditions, GLE events enhance the atmospheric electrical conductivity, reduce the columnar resistance, and modify the fair weather electric field, air–earth conduction current, and possibly the Ionospheric Potential (IP) in a way that depends on the geomagnetic cut-off rigidity of the location and the altitude. If a dust particle layer is present, GLE events tend to cancel its electrical effects in the ambient atmosphere. This means that the enhancement of the electric field and the reduction of atmospheric electrical conductivity, caused by the ion attachment to dust particles, not only tend to return to their ambient fair weather values, but they can be further modified as if the dust layer was not present. Finally, in terms of dust particles’ electrical properties, GLE events tend to modify the ion attachment mechanism, and in principle, the particle net charge, and the electric field “sensed” by them, increase. Nevertheless, since the electrical force magnitude is up to six orders of magnitude less than gravity, the increase of the particles’ electrical properties is not sufficient to modify the particle settling dynamics and settling velocities.

Dust–ion acoustic solitary waves in a collisionless magnetized five components plasma

Abstract We have derived a Korteweg–de Vries–Zakharov–Kuznetsov (KdV-ZK) equation to study the nonlinear behavior of dust–ion acoustic waves in a collisionless magnetized five components dusty plasma consisting of warm adiabatic ions, nonthermal hot electrons, isothermal cold electrons, nonthermal positrons and static negatively charged dust particulates. It is found that the coefficient of the nonlinear term of the KdV-ZK equation vanishes along different family of curves in different compositional parameter planes. In this situation, to describe the nonlinear behavior of dust–ion acoustic waves, we have derived a modified KdV-ZK (MKdV-ZK) equation. When the coefficients of the nonlinear terms of both KdV-ZK and MKdV-ZK equations are simultaneously equal to zero, then we have derived a further modified KdV-ZK (FMKdV-ZK) equation which effectively describes the nonlinear behavior of dust–ion acoustic waves. Analytically and numerically, we have investigated the solitary wave solutions of different evolution equations propagating obliquely to the direction of the external static uniform magnetic field. We have seen that the amplitude of the KdV soliton strictly increases with increasing β e, whereas the amplitude of the MKdV soliton strictly decreases with increasing β e, where β e is the nonthermal parameter associated with the hot electron species. Also, there exists a critical value β r ( c ) ${\beta }_{\text{r}}^{(\text{c})}$ of β e such that the FMKdV soliton exists within the interval β r ( c ) < β e ≤ 4 7 ${\beta }_{\text{r}}^{(\text{c})}< {\beta }_{\text{e}}\le \frac{4}{7}$ , whereas the FMKdV soliton does not exist within the interval 0 < β e < β r ( c ) $0< {\beta }_{\text{e}}< {\beta }_{\text{r}}^{(\text{c})}$ . We have also discussed the effect of different parameters of the system on solitary waves obtained from the different evolution equations.

Bifurcation analysis for dust ion acoustic waves in magnetized four-component plasmas with superthermal electrons

In collisionless, dissipative, and magnetized dusty plasma, the propagation of nonlinear dust-ion-acoustic (DIA) solitary and shock waves has been studied, whose constituents are cold positive ions, negative ions obeying the Boltzmann distribution, superthermally distributed electrons and positively charged stationary dust particles. The Korteweg-de Vries–Burgers (KdVB) equation is derived using the reductive perturbation method. This equation is solved using the tangent hyperbolic method, yielding a shock wave solution. Also, other interesting physical solutions and the corresponding electric field are determined. By applying the bifurcation theory to the planar dynamical system of the derived KdVB equation under two conditions and , the presence of solitary wave solutions and periodic traveling wave solutions has been established. According to both numerical and analytical investigations, The basic properties of dust ion acoustic waves are significantly modified by the influence of superthermal electrons, viscosity coefficients, and the existence of an external magnetic field. The current results could help in a full understanding and studying of plasma waves in both space and astrophysical environments (such as the magnetospheres of Saturn and pulsars) and also in the laboratory.

Tunable rheological behaviour of magnetized complex plasma

The shear viscosity (η) of a 3D liquid dusty plasma has been estimated as a function of magnetic field (B) and normalized ion flow velocity (M) from the simulation data using Green–Kubo formalism with the help of Langevin dynamics simulation. It has been shown that in the strongly correlated liquid state, complex plasma may exhibit sharp changes in viscosity with magnetic field and ion drift velocity. In presence of ion drift, an oscillatory and attractive wake potential develops among charged dust particles immersed in a plasma. The amplitude of this wake potential can be modulated by applying an external magnetic field. In this work, we explore how an external magnetic field influences the rheological properties of complex plasma via anisotropic wake potential. It is observed that the rheological property of such plasma depends on the dominant interaction operating among the particles and can be controlled by applying an external magnetic field. A novel regime of magnetic field is observed in which strongly correlated complex plasma liquid exhibits a sharp response to an external magnetic field. Due to this unique property, complex plasma may be used as a platform to study magneto-rheological characteristics of soft matter and there is a possibility of using dusty plasma as a magneto-rheological material in near future.