Non-Newtonian Viscosity of Complex-Plasma Fluids

Abstract

Investigations of shear flows in three-dimensional complex-plasma fluids produced in a dc discharge were carried out. The shear was induced either by an inhomogeneous gas flow or by a laser beam. The viscosity of complex plasmas was measured over a broad range of shear rates, up to the hydrodynamic limit when the discreteness becomes important. Analysis of the measurements reveals non-Newtonian behavior of complex plasmas accompanied by substantial shear thinning.

Kelvin-Helmholtz instability in non-Newtonian complex plasma

“…In case of complex plasma, the experimentally verified model for the kinematic viscosity ν(γ) with shear rate γ, given in Ref. 11 can be written as…”

“…To take into account this experimental condition following ref 11 we have included another space dependent term Ax 2 in RHS of Eq. (6) where A is the gas drag coefficient.…”

Overestimation of Viscosity by the Green-Kubo Method in a Dusty Plasma Experiment

“…To the best of our knowledge, all previous dusty plasma experimenters who have reported values for the viscosity used a hydrodynamic method [47,[53][54][55][56][57][58][59][60][61], except for Feng et al [48,51] who used the GK method with an input of experimental data. While Feng et al [51] compared their experimental GK result to an earlier hydrodynamic result [54], that comparison did not test the applicability of the GK method as the conditions in the two experiments were different.…”

Modelling of Voids in Complex Radio Frequency Plasmas

“…Figure 8a shows the distribution of dust particles with a radius of 9 μm in a discharge driven at 32 V, at 27 Pa. When particles of 3.4 μm radius are released in the midplane, they form lanes [3], drifting toward the center. Figure 8b shows the radial force acting www.cpp-journal.org on the large and small grains.…”