Hannover 2010 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 7: Poster: Dusty Plasmas

P 7.2: Poster

Dienstag, 9. März 2010, 16:00–18:00, Lichthof

Shell formation in spherically trapped plasmas — •Hanno Kählert and Michael Bonitz — ITAP, Christian-Albrechts Universität zu Kiel, 24098 Kiel

Yukawa balls are spherical dust crystals, where the particles arrange on concentric shells [1]. Compared to confined ions the interaction between the dust particles is screened, which has been shown to affect the shell occupation of the ground state and the probability of metastable states. Here we study dynamical processes in a trapped Yukawa plasma by means of Langevin dynamics simulations. By cooling a weakly correlated initial state towards the strong coupling regime, the formation of concentric shells is oberved. The time scales in the emergence of the shell structure are analyzed and the dependence of the dynamics on screening and friction is investigated. While in systems with Coulomb interaction the shells clearly emerge at the cluster boundary, they appear almost simultaneously for sufficiently large screening. Monte Carlo simulations are used to show that the sequence, in which radial order is established, is determined by the confinement potential [2].

[1] O. Arp et al., Phys. Rev. Lett. 93, 165004 (2004)

[2] H. Kählert and M. Bonitz, accepted for publication in Phys. Rev. Lett., arXiv:0909.2148