Stuttgart 2012 – wissenschaftliches Programm

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EP: Fachverband Extraterrestrische Physik

EP 4: Numerische Modellierung

EP 4.4: Vortrag

Dienstag, 13. März 2012, 17:45–18:00, V55.02

Transition between different anomalous diffusion regimes in charge-fluctuating dusty plasmas — •Andreas Kopp¹ and Yuri A. Shchekinov² — ¹IEAP, Christian-Albrechts-Universität zu Kiel, 24118 Kiel, Germany — ²Department of Space Physics, Southern Federal University, Rostov on Don, 344090, Russia

We present simple numerical simulations of random walks in a magnetized dusty plasma, in which we treat the dust as test particles in a 2D configuration with a magnetic field perpendicular to this plane. The diffusive aspect is brought in by randomly changing the parameters governing the resulting paths. Applying this to the dust charge we study the perpendicular diffusion for different values of the ratio of the time-scale for recharging to that for gyration. Increasing this single parameter in our simulations we observe for the first time a transition from subdiffusion via a wide plateau of normal or quasidiffusion to superdiffusion in the same configuration. The crucial point here is that when the recharging time is long there are phases of the dust motion, in which the particles are uncharged and, thus, can perform ``ballistic'' lights. On the other hand for short recharging dust grains are more tightly coupled to the magnetic field and therefore the random motions are supressed.