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Author: Morfill, G. E. × Publisher: [London] : IOP ×

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Now showing 1 - 4 of 4
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    Large-scale steady-state structure of a 2D plasma crystal
    ([London] : IOP, 2003) Zhdanov, S.; Quinn, R. A.; Samsonov, D.; Morfill, G. E.
    An analytical model, based on a simple physical analogy, and a non-linear analytic/numerical model of the large-scale structure (averaged over the size of a single cell) of a two-dimensional (2D) lattice have been developed. In the first model, a physical analogy between the lattice layer steady state and the stressed state of a rotating solid body was used to derive the model equations and the model is shown to be in good agreement with the results of a 2D simulation. The non-linear model is derived from the force balance between external and internal forces in the continuum limit and compares favourably with an experimental example.
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    Mutual interactions of magnetized particles in complex plasmas
    ([London] : IOP, 2003) Yaroshenko, V. V.; Morfill, G. E.; Samsonov, D.; Vladimirov, S. V.
    Various mutual dust-dust interactions in complex plasmas, including the forces due to induced magnetic and electric moments of the grains are discussed. It is shown that the dipole short-range forces can be responsible for the formation of field-aligned chains. Such chains may incorporate a few tens of individual particles, as frequently observed in experiments.
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    The plasma-sheath boundary near the adaptive electrode as traced by particles
    ([London] : IOP, 2003) Annaratone, B. M.; Glier, M.; Stuffler, T.; Raif, M.; Thomas, H. M.; Morfill, G. E.
    The adaptive electrode consists of a two-dimensional array of single electrodes each individually voltage controllable to produce local modifications in the plasma edge. This paper presents an experimental study on the nature of the perturbation introduced by the DC biasing of the pixels, using suspended particles as tracers. The particles above a negative pixel show an expansion of the sheath but for high negative voltages the particle can no longer levitate. This is explained by the reduction of the RF enhancement of the charge on the particle. Under certain conditions the sheath above a positive pixel evolves into multiple double layers, setting up a negative pre-sheath far into the plasma.
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    Formation and behaviour of dust particle clouds in a radio-frequency discharge: Results in the laboratory and under microgravity conditions
    ([London] : IOP, 2003) Mikikian, M.; Boufendi, L.; Bouchoule, A.; Thomas, H. M.; Morfill, G. E.; Nefedov, A. P.; Fortov, V. E.; PKE-Nefedov Team
    In this paper we report the first observation on submicron dust particle clouds grown in a radio-frequency sputtering discharge under microgravity conditions. These results have been obtained in the PKE-Nefedov (Plasma Kristall Experiment) chamber in the framework of a French-German-Russian programme. A dust-free region, usually called the 'void', is observed in the laboratory and under microgravity conditions even with submicron particles. In this region, successive generations of particles can be grown, leading to the coexistence of particles with various sizes. Each generation of particles constitutes a cloud separated from the others by a definite sheath. Dynamics of these clouds have been investigated showing vortex-like motions or independent behaviour of small heaps of particles, emphasizing both attractive and repulsive effects between dust clouds. As these particles drastically influence the plasma properties, the growth kinetics is followed through the evolution of the discharge current.