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Recently, it was shown that it is possible to confine spherical dust clouds in a plasma. It was found that these dust clouds have a crystalline structure which differs noteably from the well known fcc, bcc and hcp order in extended crystalline systems. The experiments show that the particles arrange in nested shells with hexagonal order on individual shells. The high transparency and the rather slow time scales of Coulomb balls allow to observe individual particles with video microscopy techniques and therefore to determine the structural properties of Coulomb balls with high accuracy. This contribution presents a comparison of experimental results and MD-Simulations. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Dusty plasmas have been confined by glass walls in order to generate void-free particle structures under microgravity conditions. Different types of clouds establish in the cuvette in dependence on the rf power and dc bias applied to the multi-electrode system of the discharge device. The observations can be basically understood when applying standard force models to discharge simulation results. The various dust topologies are proposed to result from a change in the direction of the ion drag — inwards or outwards the cuvette gap. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The interaction of a supersonic projectile with a static dust cloud trapped in an rf discharge under microgravity conditions is examined. It is observed that the projectile forms a dust-free cavity in its wake. The cavity dynamics can be divided into an initial impulse and a subsequent elastic response that can be modeled by a damped harmonic oscillator. [ABSTRACT FROM AUTHOR]

Laboratory experiments with thermophoretic levitation of dust particles for gravity compensation are reported. The observed spatially extended dust clouds were investigated, e.g., the dependence of discharge parameters on the void structure. These investigations lead to the discovery of an extended parameter region where spatially extended void-free clouds can be found. The mechanism of void closure is accompanied by a spontaneous change in the discharge topology. This change becomes evident from a reversal of the wave propagation direction. [ABSTRACT FROM AUTHOR]

A chain of mutually coupled nonlinear and self-sustained oscillators is studied numerically. The simple model allows to explain the topological structure of self-excited dust-density waves under microgravity conditions. The basic properties of the model are presented and compared with experimental studies. [ABSTRACT FROM AUTHOR]