Dusty Plasma Cloud Research Articles

Interaction of the Substance of the Tsarev Meteorite with Radiation from a Powerful Gyrotron: Dusty Plasma Cloud Formation and Phase Transformations

A new approach for simulation of the interaction of space and lunar dust with the surface of spacecrafts has been proposed. The approach is based on creating a dusty plasma cloud when the substance imitating the space or lunar dust is treated with high-power pulsed microwave radiation in the developed experimental facility. The facility consists of a high-power gyrotron (75 GHz, 0.8 MW); a plasma-chemical reactor; and a diagnostic complex, which includes optical emission spectrometers and a high-speed camera. The approach has been tested using the substance of the Tsarev meteorite, which represents a typical substance of meteorites. It was found that the substance mainly keeps the phase composition; however, the particles change their morphology due to rapid heating and melting.

On the Formation of Clouds in the Dusty Ionosphere of Mars

Dusty plasma clouds observed at altitudes of about 100 km in the mesosphere of Mars have been considered. Features of the dusty ionosphere of Mars compared to the dusty ionosphere of the Earth have been listed. The equations of the model describing self-consistently dusty plasma structures in the ionosphere of Mars have been presented. This model involves features that are important for the ionosphere of Mars but are ignored when describing the dusty plasma system in the ionosphere of the Earth. In particular, the model for Mars involves effects of deceleration of dust particles because of the adhesion of condensed molecules to them. An altitude distribution of particles constituting mesospheric clouds on Mars has been calculated with the self-consistent model. It has been shown that an important factor for the formation of dusty plasma clouds in the ionosphere of Mars is the Rayleigh–Taylor instability, which limits both the maximum size of dust particles that can form dusty plasma clouds and the maximum thickness of the dusty plasma clouds.

On the Possibility of Dust Acoustic Perturbations in Martian Ionosphere

It is shown that the horizontal winds in Martian ionosphere, at the initial stage of their interaction with dusty plasma clouds at altitudes of about 100 km, can cause conditions for the excitation of dust acoustic waves due to the development of kinetic instability. The dispersion relationship of the dust acoustic waves is determined as well as their growth rate in the conditions under study. It is noted that the generation time of the dust acoustic wave is substantially long to allow the formation of nonlinear plasma wave structures, e.g., solitons. Dust acoustic solitons that propagate in Martian ionosphere in the dusty plasma clouds at altitudes of about 100 km are studied. It is shown that the increase in dust particle number density or decrease in electron number density by one order of magnitude leads to the increase of the amplitude of dust acoustic solitons by one order of magnitude. The possibility of generation of dust acoustic perturbations in Martian ionosphere should be taken into account during processing and interpretation of observation data.

Formation of Dusty Plasma Clouds at Meteoroid Impact on the Surface of the Moon

The nature of two dusty plasma clouds appearing because of the impact of a meteoroid on the surface of the Moon has been discussed. It has been shown that one of the clouds is formed by particles (or fragments) of regolith ejected into free space by a shock wave induced by the meteoroid impact on the surface of the Moon and the second cloud is formed by solidified melt droplets. The main characteristics of these clouds, including the cloud expansion rates, the characteristic sizes of particles in both clouds, and the concentrations and charges of particles, have been calculated. The calculated cloud expansion rates are in qualitative agreement with the observational data.

Influence of dust particles on the neon spectral line intensities at the uniform positive column of dc discharge at the space apparatus “Plasma Kristall-4”

Influence of the elongated dust cloud on the intensities of different neon spectral lines in visible and near ir spectral ranges in the uniform positive column has been experimentally investigated using the Russian-European space apparatus “Plasma Kristall-4” (SA PK-4) on board of the International Space Station (ISS). The investigation was performed in the low pressure (0.5 mbar) direct current (dc, 1 mA) gas discharge in neon. Microgravity allowed us to perform experiments with a large dust cloud in the steady-state regime. To avoid the dust cloud drift in the dc electric field a switching dc polarity discharge mode has been applied. During the experiment a dust cloud of 9 mm in diameter in the discharge tube of 30 mm in diameter with the length of about 100 mm has been observed in the steady-state regime. In this regard, the intensities of neon spectral lines corresponding to 3p → 3s electronic transitions have increased by a factor of 1.4 times, while the intensities of neon spectral lines corresponding to 3d → 3p electronic transitions have increased by a factor of 1.6 times. The observed phenomenon is explained on the basis of the Schottky approach by a self-consistent rising dc electric field in the dusty plasma cloud resulting in an increase of the electron temperature.

Elongated dust clouds in a uniform DC positive column of low pressure gas discharge

Experimental investigations of the formation of elongated dust clouds and their influence on the plasma glow intensity of the uniform direct current (DC) positive column (PC) have been performed under microgravity conditions. For the axial stabilization of the dust cloud position a polarity switching DC gas discharge with a switching frequency of 250 Hz was used. During the experiment, a spontaneous division of one elongated dust cloud into two smaller steady state dust clouds has been observed. Quantitative data on the dust cloud shape, size and dust number density distribution were obtained. Axial and radial distributions of plasma emission within the 585.2 nm and 703.2 nm neon spectral lines were measured over the whole discharge volume. It has been found that both spectral line intensities at the dust cloud region grew 1.7 times with respect to the undisturbed positive column region; in this the 585.2 nm line intensity increased by 10% compared to the 703.2 nm line intensity. For a semi-quantitative explanation of the observed phenomena the Schottky approach based on the equation of diffusion was used. The model reasonably explains the observed glow enhancement as an increasing of the ionization rate in the discharge with dust cloud, which compensates ion-electron recombination on the dust grain surfaces. In this, the ionization rate increases due to the growing of the DC axial electric field, and the glow grows directly proportional to the electric field. It is shown that the fundamental condition of the radial stability of the dusty plasma cloud is equal to the ionization and recombination rates within the cloud volume that is possible only when the electron density is constant and the radial electric field is absent within the dust cloud.

Externally excited planar dust acoustic shock waves in a strongly coupled dusty plasma under microgravity conditions

The formation and dissipation of an externally excited planar dust acoustic shock wave in a three-dimensional uniform dust cloud has been observed under microgravity conditions. The experiment has been performed in the dc gas discharge chamber ‘Plasma Kristall-4’ (Fortov et al 2005 Plasma Phys. Control. Fusion 47 B537) on board the A300 Zero-G airplane. The shock Mach number and compression factor reached 3.5 and 6, correspondingly, with a shock width of about the interparticle distance. Due to the utilization of the polarity-switching dc discharge mode and application of the Rankine–Hugoniot relations, the dust particle electrostatic pressure was determined and the Hugoniot percussive adiabat for the dust subsystem was derived. The obtained data were simulated using thermodynamic properties of highly nonideal Debye–Hückel (Yukawa) systems. Comparison of the experimental and simulated data has demonstrated that the screening length in a dense dusty plasma is not determined by the total ion number density, but rather by those ‘effective’ ions which are not bounded by negatively charged dust grains. Thus, this work presents a new experimental approach for the investigation of the dense dusty plasma clouds.

Vapor Phase Deposition of Coatings onto Dust Particles in Combined Plasma

Nickel coatings on polydisperse microparticles have been deposited from vapor phase in combined RF discharge-electron beam plasma. Features of the behavior of a dusty plasma cloud in the course of evaporation and deposition of coatings are considered.

Experimental observation of dust-acoustic wave turbulence

Spontaneously excited dust acoustic oscillations are studied in a dusty plasma cloud that is in the strongly coupled fluid regime. As the gas pressure in this DC glow discharge experiment is reduced in a controlled manner the oscillations are seen to change from a coherent to a turbulent state through higher harmonic excitations. A simple explanation of the nonlinear features of the saturated spectrum is provided using a viscoelastic theory of dusty plasmas.

Spontaneous dust mass rotation in an unmagnetized dusty plasma

We report experimental observations of spontaneous mass rotation of a strongly coupled dusty plasma cloud without external magnetic field. The rotating structure resembles a convective cell pattern in the vertical plane and shows clear evidence of collective behavior as well as the influence of gravity on its angular speed. Vortex motion of dust cloud was followed right from the equilibrium state. It is identified that dust charge gradient perpendicular to gravity play important role in the generation of vortex motion.

Effect of selective coagulation of the like charged particles in a dusty plasma trap

The phenomenon of selective coagulation of the like charged disperse particles in dusty plasma was theoretically predicted and experimentally revealed. The effect lies in sharp acceleration of coagulation processes after injection into a plasma trap particles which sizes appreciably exceed Debye length and the average size of the particles initially forming a dusty plasma cloud. The absorption process of the fine fraction by the larger particles takes place.

A workshop on dusty plasmas

“Dusty plasmas” is the name given to plasmas heavily laden with charged dust grains that, together with the surrounding ions and electrons, constitute a new kind of plasma regime. Such plasmas exist in the rings of planets, in the atmospheres of comets, and in interstellar dust clouds. The dust grains are strongly coupled to the fields and particles in the plasma through their electrical charges. As a result, the motions of the grains may be dominated by electric and magnetic forces, and collective effects can play an important role. This field of study is receiving increased attention because of the observations of dust during recent spacecraft missions to the planets and comets, together with the dawning recognition that the evolution of dusty plasma clouds in space may be quite different from that of nondusty clouds.