702 research outputs found

    A scaling law for the dust cloud in radio frequency discharge under microgravity conditions

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    We employ the approximation of overlapped scattering potentials of charged dust particles exposed to streaming ions to deduce the "equation of state" for a stationary dust cloud in the radio frequency discharge apart from the void dust boundary. The obtained equation defines the potential of a dust particle as a function of the ion number density, the mass of a carrier gas atom, and the electron temperature. A scaling law that relates the particle number density to the particle radius and electron temperature in different systems is formulated. Based on the proposed approach the radius of a cavity around a large particle in the bulk of a cloud is estimated. The results of calculation are in a reasonable agreement with the experimental data available in literature.Comment: 10 pages, 7 figures, and 1 tabl

    Onset of cavity deformation upon subsonic motion of a projectile in a fluid complex plasma

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    We study deformation of a cavity around a large projectile moving with subsonic velocity in the cloud of small dust particles. To solve this problem, we employ the Navier--Stokes equation for a compressible fluid with due regard for friction between dust particles and atoms of neutral gas. The solutions shows that due to friction, the pressure of dust cloud at the boundary of the cavity behind the projectile can become negative, which entails formation of a microscopic void free from dust particles -- the cavity deformation. Corresponding threshold velocity is calculated, which is found to decrease with increasing cavity size. Measurement of such velocity makes it possible to estimate the static pressure inside the dust cloud.Comment: 7 pages, 3 figure

    Thermodynamic Properties of Correlated Strongly Degenerate Plasmas

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    An efficient numerical approach to equilibrium properties of strongly coupled systems which include a subsystem of fermionic quantum particles and a subsystem of classical particles is presented. It uses an improved path integral representation of the many-particle density operator and allows to describe situations of strong coupling and strong degeneracy, where analytical theories fail. A novel numerical method is developed, which allows to treat degenerate systems with full account of the spin scatistics. Numerical results for thermodynamic properties such as internal energy, pressure and pair correlation functions are presented over a wide range of degeneracy parameter.Comment: 8 pages, 4 figures, uses sprocl.sty (included) to be published in "Progress in Nonequilibrium Green's functions", M. Bonitz (Ed.), World Scientific 200

    Thermodynamic properties and electrical conductivity of strongly correlated plasma media

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    We study thermodynamic properties and the electrical conductivity of dense hydrogen and deuterium using three methods: classical reactive Monte Carlo (REMC), direct path integral Monte Carlo (PIMC) and a quantum dynamics method in the Wigner representation of quantum mechanics. We report the calculation of the deuterium compression quasi-isentrope in good agreement with experiments. We also solve the Wigner-Liouville equation of dense degenerate hydrogen calculating the initial equilibrium state by the PIMC method. The obtained particle trajectories determine the momentum-momentum correlation functions and the electrical conductivity and are compared with available theories and simulations