Viscosity calculated in simulations of strongly coupled dusty plasmas with gas friction

A two-dimensional strongly coupled dusty plasma is modeled using Langevin and frictionless molecular dynamical simulations. The static viscosity eta and the wave-number-dependent viscosity eta(k) are calculated from the microscopic shear in the random motion of particles. A recently developed method of calculating the wave-number-dependent viscosity eta(k) is validated by comparing the results of eta(k) from the two simulations. It is also verified that the Green-Kubo relation can still yield an accurate measure of the static viscosity eta in the presence of a modest level of friction as in dusty plasma experiments. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3560584]