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P: Fachverband Plasmaphysik

P 11: Poster: Staubige Plasmen

P 11.4: Poster

Dienstag, 31. März 2009, 17:30–19:30, Foyer des IfP

Superdiffusion in dusty plasmas — •Torben Ott and Michael Bonitz — CAU zu Kiel, ITAP, Leibnizstraße 15, D-24098 Kiel

Recent experiments [1] and simulations [2] have shown that the diffusion in quasi-two-dimensional dusty plasmas does not follow the simple space-time relation ⟨ | r(t) |²⟩ ∼ t which is implied by Fick’s law for random walkers. Instead of normal (Fickian) diffusion, these systems exhibit a superdiffusive behaviour which is characterized by ⟨ | r(t) |²⟩ ∼ t^γ, where γ is the diffusion exponent and γ>1 for superdiffusion. This implies that no meaningful (time independent) self-diffusion coefficient D can be defined for such two-dimensional systems.

We present results from classical molecular dynamics simulation for the diffusion in two-dimensional dusty plasma systems which are modelled by a Yukawa interaction. The influence of the coupling strength (coupling parameter Γ), the interaction range (inverse Debye length κ) and the effect of dissipation on the strength of superdiffusion (as measured by the diffusion exponent γ) are investigated.

[1] B. Liu and J. Goree, PRL 100, 055003 (2008)

[2] T. Ott, M. Bonitz, Z. Donkó, and P. Hartmann, PRE 78, 026409 (2008)