Processes In Dusty Plasmas Research Articles

On Dusty Plasma Processes in the Physics of Comets

On Dusty Plasma Processes in the Physics of Comets

Wave Processes in Dusty Plasma near the Mercury’s Surface

Wave processes in dusty plasma near the surface of Mercury are discussed. The near-surface layers of Mercury’s exosphere have a number of common features with those of the exosphere of the Moon, e.g., there are dust particles above the illuminated side of both cosmic bodies that become positively charged due to the photoelectric effect. Mercury has its own magnetosphere that protects the surface from particles of the solar wind. However, the solar wind can reach the surface of the planet near the magnetic poles. Therefore, dust particles of the same size get different charges depending on their localization above the Mercury’s surface. A drift wave turbulence can appear in dusty plasma in the magnetic field near the Mercury’s surface in the presence of gradient of electron concentration. The solar wind that streams at speeds of about 400 km/s relative to plasma near the surface of the planet can induce longitudinal electrostatic oscillations with frequencies determined by the electron plasma frequency. We analyze wave processes taking into account the difference in parameters at aphelion and perihelion of the Mercury’s orbit, along with the fact whether the dust particles are located near the magnetic poles or far from them.

Wave Processes in Dusty Plasma near the Mercury’s Surface

Wave Processes in Dusty Plasma near the Mercury’s Surface

Traveling wave solutions of a coupled Schrödinger-Korteweg-de Vries equation by the generalized coupled trial equation method

The coupled Schrödinger-Korteweg-de Vries equation is a critical system of in nonlinear evolution equations. It describes various processes in dusty plasma, such as Langmuir waves, dust-acoustic waves, and electromagnetic waves. This paper uses the generalized coupled trial equation method to solve the equation. By the complete discrimination system for polynomial, a series of exact traveling wave solutions are obtained, including discontinuous periodic solutions, solitary wave solutions, and Jacobian elliptical function solutions. In addition, to determine the existence of the solutions and understand their properties, we draw three-dimensional images of the modules of the solutions with Mathematica. We obtain more comprehensive and accurate solutions than previous studies, and the results give the system more profound physical significance.

Thermodynamic processes in dusty plasma

Here, we propose a thermodynamic model for dusty plasma, where the dust is confined in a small volume within a large plasma background by external fields. In this model, the parameters of dust, e.g. Helmholtz energy, pressure, entropy and enthalpy, etc. can be calculated for given dust density and temperature. The model is solved analytically in the mean field (gaseous) limit and various processes associated with the gaseous phase of dust, e.g. adiabatic/isothermal/constant internal energy expansion/compression, specific heat, free expansion within the plasma background, and the dispersion of novel acoustic waves are studied. Some predictions of the model, e.g. electrostatic pressure of the dust and the isothermal equation of state, have been earlier verified in experiments and numerical simulations. The model is compared with an earlier thermodynamic model of dusty plasma proposed by Hamaguchi and Farouki.

The electrical conductivity of weakly ionized plasma containing dust particles

The effect of charged dust particle on the electrical conductivity of weakly ionized dusty plasma is investigated. It is shown that the additional collision provided by charged dust particles can significantly alter the electrical conductivity of electron–ion plasma. The numerical results indicated that these effects are mainly determined by dust radius, density as well as the charge numbers on dust surface. The obtained results will support an enhanced understanding of the electromagnetic wave propagation processes in dusty plasma.

Cyclic evolution of the electron temperature and density in dusty low-pressure radio frequency plasmas with pulsed injection of hexamethyldisiloxane

Optical emission spectroscopy was used to analyze the very-low-frequency cyclic evolution of the electron energy and density caused by repetitive formation and loss of dust nanoparticles in argon plasmas with pulsed injection of hexamethyldisiloxane (HMDSO, [CH3]6Si2O). After elaborating a Boltzmann diagram for Ar high-lying levels and a collisional-radiative model for Ar 2p (Paschen notation) states, temperatures characterizing the low- and high-energy parts of the electron population were calculated. Relative electron densities were also estimated from relative line emission intensities. Both temperatures increase when the dust occupation increases, and then decrease when dust is lost. The opposite trend was observed for the electron density. Such cyclic behaviors of the electron energy and electron density in the HMDSO-containing plasmas are in good agreement with the evolution processes in dusty plasmas, in which the formation of negative ions followed by an electron attachment on the surfaces of the nanoparticles is a critical phenomenon driving dust growth.

Wave processes in dusty plasma near the Moon’s surface

A plasma—dust system in the near-surface layer on the illuminated side of the Moon is described. The system involves photoelectrons, solar-wind electrons and ions, neutrals, and charged dust grains. Linear and nonlinear waves in the plasma near the Moon’s surface are discussed. It is noticed that the velocity distribution of photoelectrons can be represented as a superposition of two distribution functions characterized by different electron temperatures: lower energy electrons are knocked out of lunar regolith by photons with energies close to the work function of regolith, whereas higher energy electrons are knocked out by photons corresponding to the peak at 10.2 eV in the solar radiation spectrum. The anisotropy of the electron velocity distribution function is distorted due to the solar wind motion with respect to photoelectrons and dust grains, which leads to the development of instability and excitation of high-frequency oscillations with frequencies in the range of Langmuir and electromagnetic waves. In addition, dust acoustic waves can be excited, e.g., near the lunar terminator. Solutions in the form of dust acoustic solitons corresponding to the parameters of the dust—plasma system in the near-surface layer of the illuminated Moon’s surface are found. Ranges of possible Mach numbers and soliton amplitudes are determined.

Future lunar missions and investigation of dusty plasma processes on the Moon

AbstractFrom the Apollo era of exploration, it was discovered that sunlight was scattered at the terminators giving rise to “horizon glow” and “streamers” above the lunar surface. Subsequent investigations have shown that the sunlight was most likely scattered by electrostatically charged dust grains originating from the surface. A renaissance is being observed currently in investigations of the Moon. The Luna-Glob and Luna-Resource missions (the latter jointly with India) are being prepared in Russia. Some of these missions will include investigations of lunar dust. Here we discuss the future experimental investigations of lunar dust within the missions of Luna-Glob and Luna-Resource. We consider the dusty plasma system over the lunar surface and determine the maximum height of dust rise. We describe mechanisms of formation of the dusty plasma system over the Moon and its main properties, determine distributions of electrons and dust over the lunar surface, and show a possibility of rising dust particles over the surface of the illuminated part of the Moon in the entire range of lunar latitudes. Finally, we discuss the effect of condensation of micrometeoriod substance during the expansion of the impact plume and show that this effect is important from the viewpoint of explanation of dust particle rise to high altitudes in addition to the dusty plasma effects.

Screening in weakly ionized dusty plasmas; effect of dust density perturbations

The screening of the charge of a non-emitting dust grain immersed in a weakly ionized dusty plasma is studied on the basis of a self-consistent hydrodynamic description. The dust number density is considered large enough so that the test grain is not isolated from other grains and dust collective effects are important. Not only dust charge perturbations but also dust density perturbations are taken into account, the latter are shown to have a strong effect on both the short and long range part of the potential. The realization of collective attraction via the newly obtained potential is discussed, a mechanism that could be central to the understanding of phase-transitions and self-organization processes in dusty plasmas.

Dusty plasma processes in Earth's environments containing nano- and microscale grains

AbstractReview of plasma processes in the Earth's environments containing nano- and microscale grains is presented. Possible observational manifestations of dusty ionospheric plasmas during high-speed meteor showers are described. A unified explanation of ionization properties of the polar mesosphere under summer conditions is given. Dusty plasma processes are also considered in application to active geophysical rocket experiments which involve release of some gaseous substance in near-Earth space, the origin of the primary Earth's crust, hydrosphere and atmosphere, and global electromagnetic Schumann resonances.

Simulation of kinetic processes in the Nuclear‐Excited Helium Non‐Ideal Dusty Plasma

AbstractThe paper is devoted to the studying of kinetic processes in the nuclear‐excited plasma of the helium gas with the fine uranium (or its chemical compounds) particles admixture. A new theoretical model for the mathematical simulation of the kinetic processes in dusty plasma of helium gas was developed. The main goal of this investigation is to determine possibilities of a creation of non‐ideal dusty plasma, containing nano‐ and micro‐particles, and excited by fission fragments (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Dusty Plasma Processes in Geophysics

Review of dusty plasma phenomena in application to geophysical problems is presented. Possible observational manifestations of dusty ionospheric plasmas during high-speed meteor showers are described. A unified explanation of ionization properties of the polar mesosphere under summer conditions is given. Dusty plasma processes are also considered in application to active geophysical rocket experiments which involve release of some gaseous substance in near-Earth space, the origin of the primary Earth’s crust, hydrosphere, and atmosphere, and global electromagnetic Schumann resonances.

Combined Effect of Secondary Electron Emission, Plasma Ion and Electron Number Density Variation due to Dust Charging and Ionization-Recombination Processes on Dust Ion Acoustic Wave Propagation

In a dusty plasma, in addition to influencing the dust charge state the secondary electron emission also leads to an enhancement of the electron number density. For proper accounting for secondary electron emission effect one has therefore, for the sake of consistency, also to take into account the ambient electron and ion loss due to charging collisions. The existence of a steady state for the dusty plasma is possible only through compensation of such particle losses or gain – a likely candidate for which are ionization and recombination processes in dusty plasma. Taking into account the combined effects all these processes and assuming that the frequencies of the various types of interparticle collisions associated with the above-mentioned processes are much less than the dust ion acoustic (DIA) frequency it is shown that a small perturbation of the steady state of the dusty plasma may result in DIA wave growth provided the ionization rate is sufficiently high. Threshold values of the ratio of the ionization rate to recombination rate depending on different plasma parameters are shown graphically. The analysis presented is restricted to the case when the dust charge remains negative. It is seen that instability persists even when there is no secondary emission. The threshold for instability is lower for smaller values of the dimensionless charge parameter z0 = Zd0e2/aTe when secondary emission takes place, compared to the case when it is absent. The situation tends to get reversed as z0 increases. The possibility of the existence of such instability was not noted earlier.

Basics of dusty plasma

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.

Progress in the study of dusty plasmas

While the study of dust–plasma interactions is by no means new, early progress in the field was slow and uneven. It received a major boost in the early 1980s with the Voyager spacecraft observations of peculiar features in the Saturnian ring system (e.g. the `radial spokes') which could not be explained by gravitation alone and led to the development of the gravito-electrodynamic theory of dust dynamics. This theory scored another major success more recently in providing the only possible explanation of collimated high-speed beams of fine dust particles observed to sporadically emanate from Jupiter by the Ulysses and Galileo spacecrafts.These dynamical studies were complimented in the early 1990s by the study of collective processes in dusty plasmas. Not only has this led to the discovery of a whole slew of new wave modes and instabilities with wide ranging consequences for the space environment, it also spurred laboratory studies leading to the observation of several of them, including the very low frequency dust acoustic mode, which can be made strikingly visual by laser light scattering off the dust.The most fascinating new development in dusty plasmas, which occurred about 7 years ago, was the crystallization of dusty plasmas in several laboratories. In these so-called `plasma crystals', micrometre-sized dust, which are either externally introduced or internally grown in the plasma, acquire large negative charges and form Coulomb lattices as was theoretically anticipated for some time. This entirely new material, whose crystalline structure is so strikingly observed by laser light scattering, could be a valuable tool for studying physical processes in condensed matter, such as melting, annealing and lattice defects. Recognizing the crucial role of gravity on the crystal structure, microgravity experiments have already been performed in aircraft, sounding rockets, the Mir Space Station, and most recently in the International Space Station, leading to interesting new phenomena and insights.Dust–plasma interactions are also important in the industrial laboratory. The nuisances and hazards related to dust charging in mills, granaries and mines have been known for a long time. At the same time dust charging has been effectively used in electrostatic precipitation, separation and spraying as well as in the sterilization and electrophoresis of biological materials. Also, plasma processing is now used in the semiconductor manufacturing industry. The condensation and transport of fine dust particles in these high-density, low-temperature plasmas leading to product yield loss, is a significant problem facing this multibillion dollar industry, and is expected to become more important as feature sizes decrease in the future. The role of dust–plasma interactions in magnetic fusion devices, where dust could grow in the edge of the fusion plasma discharge itself and be subsequently transported elsewhere, is also beginning to receive attention, lately.I expect this rapid growth will continue well into the foreseeable future. While the richness and complexity of the field, with numerous unresolved and challenging problems, will continue to stimulate the field, several forthcoming space missions (e.g. Cassini and Rosetta) will provide important observational boosts. The fascinating high-resolution Hubble Space Telescope photographs of dusty cosmic regions, such as those where new stellar and planetary formation are taking place in plain sight (the so-called cosmic nurseries), is only now beginning to underscore the importance of dusty plasma phenomena in these vital astrophysical regions. Finally, the proposed International Microgravity Plasma Facility, dedicated to dusty plasma studies in the International Space Station within the next few years, will provide a major boost to this fascinating field.

Some Physical Processes in Dusty Plasmas

Ionized gases containing fine (μm to sub-μm sized) charged dust grains, referred to as dusty plasmas, occur in diverse cosmic and laboratory environments. Dust occurs in many space and astrophysical environments, including planetary rings, comets, the Earth's ionosphere, and interstellar molecular clouds. Dust also occurs in laboratory plasmas, including processing plasmas, and crystallized dusty plasmas. Charged dust can lead to various effects in a plasma. In this review, some physical processes in dusty plasmas are discussed, with an emphasis on applications to dusty plasmas in space. This includes theoretical work on several wave instabilities, the role of dust as an electron source, and Coulomb crystals of positively charged dust.

New collective processes in dusty plasmas: applications to space and laboratories

The status of numerous collective processes in dusty plasmas ispresented. The focus will be on theoretical and experimental studies of novel waves and instabilities, effects of non-spherical rotating dust grains, as well as some nonlinear structures (such as dust ion-acoustic shocks and holes, Mach cones, dust voids, vortices, etc). The latter are typical in astrophysical settings and inmicrogravity experiments. It appears that collective processes in a dusty plasma would have excellent future perspectives in the twenty first century, because they have not only potential applications in cosmic and laboratory environments, or in understandingthe physics of our dusty universe, but also in advancing our scientificknowledge in inter-disciplinary areas of science.