Shear Flows and Shear Viscosity in a Two-Dimensional Yukawa System (Dusty Plasma)

TL;DR

This study experimentally measures the shear viscosity of a two-dimensional dusty plasma with Yukawa interactions by inducing shear flow and analyzing particle velocities, providing insights into its fluid properties.

Contribution

It introduces a novel experimental approach to measure shear viscosity in a 2D dusty plasma using laser-driven shear flow and velocity profile fitting.

Findings

Shear viscosity is approximately 1 mm^2/s.

Shear viscosity depends on plasma parameters and applied shear stress.

Shear-induced melting observed in the monolayer.

Abstract

The shear viscosity of a two-dimensional liquid-state dusty plasma was measured experimentally. A monolayer of highly charged polymer microspheres, with a Yukawa interaction, was suspended in a plasma sheath. Two counter-propagating Ar laser beams pushed the particles, causing shear-induced melting of the monolayer and a shear flow in a planar Couette configuration. By fitting the particle velocity profiles in the shear flow to a Navier-Stokes model, the kinematic viscosity was calculated; it was of order 1 mm^2/s, depending on the monolayer's parameters and shear stress applied.