Düsseldorf 2007 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 7: Poster
P 7.41: Poster
Montag, 19. März 2007, 16:30–18:30, Poster A
Structural transitions in screened 3D Coulomb crystals — •Daniel Asmus1, Volodymyr Golubnichiy1, Patrick Ludwig1,2, and Michael Bonitz1 — 1CAU zu Kiel, ITAP, Leibnizstrasse 15, D-24098 Kiel — 2Universität Rostock, Institut für Physik, Universitätsplatz 3, D-18051 Rostock
Recent experimental [1] and theoretical [2,3] work has shown that a classical one-component plasma in a 3D parabolic trap undergoes in the strong coupling limit a transition to a highly ordered crystalline state with a nested shell structure. In the case of pure Coulomb interaction a Mendeleev-type table was found including characteristic occupation numbers, shell closures, and unusual stable "magic" configurations, see Ref. [2,3]. Here we extend this work to the more general case of a statically screened Coulomb interaction which explains the experimental observations [4]. We present a detailed analysis of the shell configurations and energies of the ground and lowest metastable states for a large range of screening parameters κ and particle numbers N ≤ 60. Interestingly, for certain values of κ and N, reentrant shell filling behavior and triple points are observed. The structural transitions of the spherical Yukawa crystals have been analysed by means of extensive high-accuracy molecular dynamics computer simulations based on a optimized annealing algorithm.
[1] O. Arp et al., Phys. Rev. Lett. 93, 165004 (2004).
[2] R.W. Hasse, V.V. Avilov, Phys. Rev. A 44, 4506 (1991).
[3] P. Ludwig et al., Phys. Rev. E 71, 046403 (2005)
[4] M. Bonitz et al., Phys. Rev. Lett. 96, 075001 (2006)