Abnormal Diffusion in Wind-tree Lattice Gases
Philippe M. Binder
Center for Nonlinear Studies, MS-B258,
Los Alamos National Laboratory, Los Alamos, NM 87545, USA
and
Applied Physics Section, Dunham Laboratory,
Yale University, New Haven, CT 06520, USA
Abstract
It is found numerically that a two-dimensional left-turning particle-scatterer system does not diffuse for scatterer densities slightly above one-half, or greater. For smaller densities, the diffusion coefficient is much lower than what the Boltzmann approximation predicts; this is caused by orbiting events.
An isotropic-scattering model with reflective impurities also shows deviations from the diffusion equation for various densities of isotropic and reflective scatterers, caused by retracing events.
