Fluctuations in dusty plasmas (original) (raw)
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Observation of the Effects of Dust Particles on Plasma Fluctuation Spectra
Physical Review Letters, 2007
Charged dust particles are theoretically expected to modify the amplitude and spectrum of plasma fluctuations, and this can eventually provide novel diagnostic tools. Direct experimental evidence of the effects of dust particles on the fluctuations of a low collisionality plasma is reported, in agreement with the expectations of kinetic theory.
Stochastic charge fluctuations in dusty plasmas
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 1996
We consider the stochastic properties of charge fluctuations of noninteracting particles surrounded by a stationary, undisturbed plasma of electrons and singly charged positive ions. For unscreened Coulomb interaction in the orbit-motion limit the mean particle charge and the variance of the fluctuations are proportional to the particle size. The result applies to both Maxwellian and non-Maxwellian electrons as well as to charging by ion winds. When the polarizability of the particle is included in the electrostatic interaction, both the ion and electron currents to the particle increase and the mean particle charge becomes more negative. Except for particles in the low nanometer range, the effect of the polarizability can be neglected at the electron temperatures encountered in typical plasmas.
Charge-fluctuation-induced heating of dust particles in a plasma
Physical Review E, 1999
Random charge fluctuations are always present in dusty plasmas due to the discrete nature of currents charging the dust particle. These fluctuations can be a reason for the heating of the dust particle system. Such unexpected heating leading to the melting of the dust crystals was observed recently in several experiments. In this paper we show by analytical evaluations and numerical simulation that charge fluctuations provide an effective source of energy and can heat the dust particles up to several eV, in conditions close to experimental ones. ͓S1063-651X͑99͒12110-X͔
Statistical properties of relaxing dusty plasmas
Le Journal de Physique IV, 2000
The Liouville equation is considered for relaxing dusty plasmas consisting initially of equilibrium electrons and ions as well as neutral dust particles. The plasmas relax then due to a collection ofelectrons and ions by dust particles. The free and collected electrons and ions are considered as a common subsystem described by the common whole distribution function. It is shown that this subsystem is described by a complex integral-differential equation with Non-Markovian kinetics. The general properties of dusty plasmas are important for controlled fusion devices because dust particles can be created in fusion devices due to the plasma-wall interaction and therefore can influence particle and energy fluxes to the wall.
Oscillations in a Dusty Plasma Medium
2002
Novel properties introduced by charged particulates in a plasma medium and how they influence excitation and propagation of waves are discussed. Such a medium, commonly known as dusty plasma, is generated in the near Earth environment by dust and other debris of meteoric origin and exhausts and effluents from space platforms. A novel feature of dusty plasma is that the charge to mass ratio can become a dynamical variable and represent an additional degree of freedom unavailable to a classical plasma. Charged dust particles in a plasma introduce unique potential structures and significantly alter the short and long range forces which can affect the short and long range ordering of the dust grains.
Physical Review E, 1999
A dust particle in a plasma acquires electric charge by collecting electrons and ions, and sometimes by emitting electrons. The charging currents consist of discrete charges, causing the charge to fluctuate around an equilibrium value. We developed a model yielding a general expression for the charge fluctuations' temporal autocorrelation function. Both the magnitude and characteristic time of fluctuations can be obtained, knowing the specific form of charging currents. Numerical results are presented for different charging mechanisms, including charging by thermionic and photoelectric emission. It is shown that for all charging mechanisms the amplitude of fluctuations varies as ⌬Zϭ␣ͱ͉͗Z͉͘, where ͗Z͘ is the equilibrium dust grain charge in units of electron charges. ͓S1063-651X͑99͒09004-2͔
1999
The role of neutrals in a partially ionized collisional dusty plasma is analyzed. In a magnetized inhomogeneous collisional dusty plasma, where plasma components have density gradients, neutrals can aect the instability signi®cantly. Neutral induced instability and the eect of charge variation in such a dusty plasma are investigated. Dust size can control the neutral scale length which can answer the observed density irregularities in the ionosphere. Small sized dust particles favour damping due to charge variation while large sized particles assist collisional damping.
Dusty plasmas: synthesis, structure and dynamics of a dust cloud in a plasma
The European Physical Journal Applied Physics, 2010
Plasmas are energetic media that can give birth to dust particles due to the presence of reactive gases or plasma-surface interactions. Industrial plasmas are often concerned by these dust particles that can be either unwanted or useful for the process. For fusion plasmas, production of dust particles from wall erosion is a serious issue for performance and safety reasons. In this article, some aspects of dusty plasmas with potential implications for plasma experimenters will be discussed. Convenient ways for detecting the presence or the growth of dust particles will be presented. The spatial distribution of the dust cloud during the plasma phase determines the subsequent dust particle deposition. It will be shown that some reactor regions can attract or repeal these dust particles. Finally, the dust particle dynamics after the plasma extinction will be investigated. A special attention will be paid on the residual electric charge that can stay attached on the dust particle surface and on its implications for dust particle control or deposition.
Dust in Flowing Magnetized Plasma
2009
Plasma flows occur in almost every laboratory device and interactions of flowing plasmas with near-wall impurities and/or dust significantly affects the efficiency and lifetime of such devices. The charged dust inside the magnetized flowing plasma moves primarily under the influence of the plasma drag and electric forces. Here, the charge on the dust, plasma potential, and plasma density are calculated self-consistently. The electrons are assumed non-Boltzmannian and the effect of electron magnetization and electron-atom collisions on the dust charge is calculated in a self-consistent fashion. For various plasma magnetization parameters viz. the ratio of the electron and ion cyclotron frequencies to their respective collision frequencies, plasma-atom and ionization frequencies, the evolution of the plasma potential and density in the flow region is investigated. The variation of the dust charge profile is shown to be a sensitive function of plasma parameters.
Dust acoustic and drift waves in a non-Maxwellian dusty plasma with dust charge fluctuation
Journal of Plasma Physics, 2015
The properties of dust acoustic and drift waves are investigated in a charge varying magnetized dusty plasma. The plasma is composed of non-thermal electrons and ions with dynamic dust particles. The mathematical expression which describes the dust charge fluctuation is obtained using${\it\kappa}$-distribution for both the electrons and ions. A dispersion relation is derived and analysed numerically by choosing space plasma parameters. It is found that the inclusion of variable dust charge along with the non-thermal effects of electrons and ions significantly affect linear/nonlinear properties of the dust acoustic and dust drift waves. The effects of different physical parameters including spectral index (${\it\kappa}$), dust charge number ($Z_{d}$), electron density ($n_{e}$) and ion temperature ($T_{i}$) on the wave dispersion and instability are presented. It is found that the presence of the non-thermal electron and ion populations reduce the growth rate of the instability which...