Jena 2013 – scientific programme
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P: Fachverband Plasmaphysik
P 14: Poster: Komplexe und Staubige Plasmen
P 14.8: Poster
Thursday, February 28, 2013, 14:00–16:00, Poster EG
Phase Transitions in Spherical Dust Clusters: Analysis of Two- and Three-Particle Correlations — •Hauke Thomsen, Patrick Ludwig, and Michael Bonitz — ITAP, Christian-Albrechts-Universität zu Kiel, D-24098 Kiel
In recent years the phase transition-like crossover from a crystal to a liquid-like state has attracted high interest in particular in spherically confined dusty plasmas, e.g. [1]. While the radial melting is now well understood, here we concentrate on the loss of intra-shell order. In order to extract the relevant information from the many particle densities ρ2(r1→,r2→) and ρ3(r1→,r2→,r3→), we introduce generalized coordinates according to the system’s symmetry. By suitable integration over the invariant coordinates, we obtain the Center-Two-Particle (C2P) and Triple-Correlation-Function (TCF).
The C2P function g2(rI,rII,ϑ) depends on the radial coordinates of two particles and the angle between those with respect to the trap center [2]. It resolves both, intra-shell and inter-shell correlations. The TCF h3(bI,bII,ϕ), as a three-particle quantity depends on two pair distances and the angle between the two pair connections.
The analysis of angular correlations in the outer shell of Coulomb clusters reveals a striking similarity with the properties of extended two dimensional systems including indications for Kosterlitz-Thouless behavior, e.g. [3].
[1] J. Böning et al., Phys. Rev. Lett. 100, 113401 (2008)
[2] P. Ludwig et al., Plasma Phys. Control. Fusion 52, 124013 (2010)
[3] P. Ludwig et al., Contrib. Plasma Phys. 47, 335 (2007)