Condensed Matter Physics Seminar

Interactions of Moving Charges with 2D Strongly-Coupled Dusty Plasmas

Lu-Jing Hou
Department of Applied Mathematics
University of Waterloo
Tuesday, April 24, 2007
Higgins 235, 3pm

Interactions of fast-moving charges with 2D strongly-coupled dusty plasmas are studied from both numerical simulation and analytical theory, with an emphasis being put on the wave excitation in dust layers and the energy exchange between those layers and moving charges. The model system consists of a monolayer of highly charged dust particles, with an external dust particle moving parallel to it, immersed in background plasmas in a thermal quasi-equilibrium, so that all dust particles interact pairwise via a Yukawa-like potential. The Brownian Dynamics method is used to simulate interactions in full detail, enabling us to deduce the longitudinal "stopping" force and the lateral "image" force on the external particle as well as wave-propagations in the dust layer. The results are then compared with those obtained from various linear-dielectric-response models of dusty plasmas, such as Random Phase Approximation and Quasi-Localized Charge Approximation (QLCA). Good agreement is found between the QLCA and simulation results in the case of small perturbation, whereas in the opposite region nonlinear effects become significant, and the linear QLCA model becomes inadequate for describing the interaction processes.