Berlin 2005 – wissenschaftliches Programm
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P: Plasmaphysik
P 17: Staubige Plasmen 1
P 17.2: Vortrag
Montag, 7. März 2005, 11:30–11:45, HU 3059
Theoretical analysis of spherical 3D Coulomb and Yukawa crystals — •S. Kosse1, V. Golubnychiy2, P. Ludwig2, H. Baumgartner2, W.-D. Kraeft2, M. Bonitz2, and H. Fehske1 — 1Institute of Physics, Ernst-Moritz-Arndt-University Greifswald, 17487 Greifswald — 2Institute for Theoretical Physics and Astrophysics, Christian Albrechts University Kiel, D-24098 Kiel
Recently, three-dimensional spherically symmetric Coulomb crystals have been experimentally produced in ultracold ions and dusty plasmas [1]. Besides, they have been predicted to form in expanding laser-cooled neutral plasmas [2]. Here, we present a detailed theoretical analysis of these crystals. Our results are based on high precision classical Molecular dynamics simulations [3] and compared with analytical shell models. We report results for the ground state shell configuration and the lowest metastable states. Further, the cluster symmetry and stability is analyzed. A central issue is the dependence of the cluster properties on the interparticle potential which in most experiments deviates from a pure Coulomb potential. We, therefore, analyze the effect of static screening (Yukawa potential) on the crystal properties and the melting behavior. We show that the experimentally observed configuration can be accurately explained in the frame of Yukawa interaction by a suitable choice of the screening parameter.
[1] O. Arp, D. Block, A. Piel, and A. Melzer, Phys. Rev. Lett. 93, 165004 (2004); [2] T. Pohl, T. Pattard, and J.M. Rost, Phys. Rev. Lett. 92, 155003 (2004); [3] P. Ludwig, S. Kosse, and M. Bonitz, Phys. Rev. E (2005), [ArXiv:physics/0409095 and physics/0409100].