Magnetic Field Induced Shear Flow in a Strongly Coupled Complex Plasma

TL;DR

This study experimentally demonstrates how a magnetic field induces shear flow in a strongly coupled complex plasma, with observed particle rotation and shear resulting from sheath electric fields and magnetic deflection, supported by molecular dynamics simulations.

Contribution

It provides the first experimental observation of magnetic field-induced shear flow in a strongly coupled complex plasma, supported by simulation validation.

Findings

Magnetic field causes azimuthal shear flow in dust particles.

Shear flow direction depends on rf amplitude and sheath electric field.

MD simulations agree well with experimental observations.

Abstract

We address an experimental observation of shear flow of micron sized dust particles in a strongly coupled complex plasma in presence of a homogeneous magnetic field. Two concentric Aluminum rings of different size are placed on the lower electrode of a radio frequency (rf) parallel plate discharge. The modified local sheath electric field is pointing outward/inward close to the inner/outher ring, respectively. The microparticles, confined by the rings and subject to an ion wind that driven by the local sheath electric field and deflected by an externally applied magnetic field, start flowing in azimuthal direction. Depending upon the rf amplitudes on the electrodes, the dust layers show rotation in opposite direction at the edges of the ring-shaped cloud resulting a strong shear in its center. MD simulations shows a good agreement with the experimental results.