Microstructure of a liquid complex (dusty) plasma under shear

TL;DR

This study experimentally investigates the microstructure of a strongly coupled liquid in a shear flow, revealing anisotropic features and linking microstructure ellipticity to shear rate in a dusty plasma system.

Contribution

It provides the first detailed experimental analysis of microstructure anisotropy in a shear-melted dusty plasma crystal, connecting microstructural features to shear flow parameters.

Findings

Microstructure is anisotropic with axes at ±45° to flow.

Ellipticity of $g(r)$ and $S(k)$ correlates with shear rate.

Shear flow induces measurable microstructural deformation.

Abstract

The microstructure of a strongly coupled liquid undergoing a shear flow was studied experimentally. The liquid was a shear melted two-dimensional plasma crystal, i.e., a single-layer suspension of micrometer-size particles in a rf discharge plasma. Trajectories of particles were measured using video microscopy. The resulting microstructure was anisotropic, with compressional and extensional axes at around $\pm 45^{\circ}$ to the flow direction. Corresponding ellipticity of the pair correlation function $g({\bf r})$ or static structure factor $S(\bf{k})$ gives the (normalized) shear rate of the flow.