Dust Particles In Dusty Plasma Research Articles

Twisted dust acoustic waves in dusty plasmas

We examine linear dust acoustic waves (DAWs) in a dusty plasma with strongly correlated dust grains, and discuss possibility of a twisted DA vortex beam carrying orbital angular momentum (OAM). For our purposes, we use the Boltzmann distributed electron and ion density perturbations, the dust continuity and generalized viscoelastic dust momentum equations, and Poisson’s equation to obtain a dispersion relation for the modified DAWs. The effects of the polarization force, strong dust couplings, and dust charge fluctuations on the DAW spectrum are examined. Furthermore, we demonstrate that the DAW can propagate as a twisted vortex beam carrying OAM. A twisted DA vortex structure can trap and transport dust particles in dusty plasmas.

Stochastic heating of dust particles in complex plasmas as an energetic instability of a harmonic oscillator with random frequency

The paper describes the occurrence of stochastic heating of dust particles in dusty plasmas as an energy instability due to the correlations between dust grain charge and electric field fluctuations. The possibility that the mean energy (“temperature”) of dust particles can grow in time has been found both from the self-consistent kinetic description of dusty plasmas taking into account charge fluctuations [U. de Angelis, A. V. Ivlev, V. N. Tsytovich, and G. E. Morfill, Phys. Plasmas 12(5), 052301 (2005)] and from a Fokker-Planck approach to systems with variable charge [A. V. Ivlev, S. K. Zhdanov, B. A. Klumov, and G. E. Morfill, Phys. Plasmas 12(9), 092104 (2005)]. Here, a different derivation is given by using the mathematical techniques of the so called multiplicative stochastic differential equations. Both cases of “fast” and “slow” fluctuations are discussed.

Solitary inertial Alfvén waves in dusty plasmas

Linear and nonlinear inertial Alfvén waves are studied in the presence of positively and negatively charged dust in electron-ion plasmas. The Sagdeev potential approach is employed to obtain solitary inertial Alfvén waves in such a multicomponent plasma. It is found that electron density dips are formed in the super Alfvénic region, which has behavior similar to the case of electron-ion plasmas. The amplitude of the electron density dip structure is decreased in the presence of positively charged dust particles, while it is increased due to negatively charged dust particles in dusty plasmas. The numerical results are shown for an illustrative purpose. The results can be applicable to explain some aspects of solar wind interactions with the comets and planets containing dusty plasma environments.

Structure of finite two-dimensional systems of dust particles at finite temperatures

The structure of confined two-dimensional systems of dust particles in dusty plasmas is analyzed at finite temperatures by numerical simulations and theoretical approaches. The finite Yukawa system is adopted as a model for these systems and the variational method which has been successful in reproducing structures at low temperatures is extended to finite temperatures through replacement of the cohesive energy by the Helmholtz free energy recently given in the form of simple interpolation formulas. The results are compared with those of numerical simulations and their satisfactory agreement has been obtained. Finite-temperature structures presented here will be useful to evaluate the physical parameters of the two-dimensional systems of dust particles often formed near the boundary between the plasma bulk and the sheath.

Structure of spherical Yukawa clusters: A model for dust particles in dusty plasmas in an isotropic environment

The structure of spherical clusters composed of Yukawa particles is analyzed by molecular dynamics simulations and theoretical approaches as a model for dust particles in dusty plasmas in the isotropic environment. The latter condition is expected to be realized under microgravity or by active cancellation of the effect of gravity on the ground. It is found that, at low temperatures, Yukawa particles form spherical shells and, when scaled by the mean distance, the structure is almost independent of the strength of screening including the case of the Coulomb interaction. The positions and populations of shells and the conditions for the change of the number of shells are expressed by simple interpolation formulas. Shells have an approximately equal spacing close to that of triangular lattice planes in the bulk close-packed structures. It is shown that, when the cohesive energy in each shell is properly taken into account, the shell model reproduces the structure of spherical Yukawa clusters to a good accuracy.

Ordering of dust particles in dusty plasmas under microgravity

Structure formation of dust particles in dusty plasmas under microgravity has been simulated by the molecular dynamics method. It is shown that, at low temperatures, dust particles are organized into layered spherical shells. The number of shells is a function of the system size and the strength of screening by ambient plasma particles, while the dependency on the latter is much weaker. In the simulation, the condition of the charge neutrality satisfied by the system of dust particles and plasma particles is properly taken into account.

Kinetic theory of dusty plasmas. V. The hydrodynamic equations

The collisional hydrodynamic equations for electrons, ions, and dust particles in dusty plasmas are derived from the kinetic equations [V. N. Tsytovich and U. de Angelis, Phys. Plasmas 6, 1093 (1999)] which consistently take into account the elastic and inelastic (charging) collisions of plasma particles with dust and the effects of dust charge fluctuations. These equations are valid in the parameter regime where the collisions of plasma particles with dust dominate with respect to the binary plasma collisions. New expressions for the fluid collision frequencies, transport coefficients, viscosity, and ion drag are found and compared with previous results.

Ground State Configurations of Two-dimensional Plasma Crystals under Long-range Attractive Particle Interaction Force

The configurational properties of two-dimensional clusters of charged dust particles in dusty plasma interacting with each other via a model potential with a short-range repulsion and a long-range attraction are investigated through the Monte Carlo simulation technique. The particles are confined by a harmonic potential. For the small number of particles, a hexagonal structure of the ground state changes into a shell configuration with increasing value of the attraction parameter α. For larger clusters, the increased attraction changes the defect locations and more particles energetically suit in the center of the cluster.