Bochum 2015 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 7: Poster Session - Dusty Plasmas
P 7.11: Poster
Montag, 2. März 2015, 16:30–18:30, Foyer Audimax
Resolving phase transition in finite dust clusters — •Hauke Thomsen, Patrick Ludwig, and Michael Bonitz — ITAP, Christian-Albrechts- Universität, Kiel, D-24098, Germany
Finite systems in confining potentials are known to undergo structural transitions similar to phase transitions. Due to their inhomogeneity, the melting process is qualitatively different from extended systems. Many melting criteria rely on precise energy measurement (heat capacity, cV), on the dynamics (e.g. Lindemann criterion)[1], on critical indices or on transport properties such as diffusion[2], that are not directly accessible in experiments. Here we present a set of parameters that involve only the particle coordinates.
In numerical simulations[3], we sample the spatial pair-density as well as the three-particle density in suitable coordinates[4,5]. The next step is the computation of reduced entropies S(2) and S(3). Their temperature behavior allows us to clearly identify radial melting, intra-shell disordering as well as inter-shell angular disordering processes in spherical dust clusters. Our method is very general and not restricted to dusty plasmas. It can also be applied to other trapped systems such as quantum dots, ions in traps or atomic clusters.
References:
[1] F. Calvo, and E. Yurtsever, Eur. Phys. J. D 44, 81-91 (2007)
[2] H. Löwen et al., Phys. Rev. Lett. 70, 1557 (1993)
[3] H. Thomsen, and M. Bonitz, Phys. Rev. E (2014)
[4] P. Rehmus et al., Chem. Phys. Lett. 58, 321 (1978)
[5] H. Thomsen et al., J. Phys. D: Appl. Phys 47 383001 (2014)