Dust vortex flow analysis in weakly magnetized plasma

TL;DR

This paper analyzes dust vortex flow in weakly magnetized plasma using a 2D hydrodynamic model, revealing how magnetic field gradients and drift mechanisms influence vortex formation without non-conservative forces.

Contribution

It provides analytical solutions for dust vortex flow driven by electric and magnetic fields in a weakly magnetized plasma, highlighting the role of magnetic field gradients.

Findings

Vortex flow is driven by ambipolar electric fields generated by electron E*B drift.

Magnetic field gradients facilitate sheared E*B drift flows leading to vortex formation.

Analytical stream-function solutions show the influence of magnetic field strength and gradients.

Abstract

Analysis of driven dust vortex flow is presented in a weakly magnetized plasma. The 2D hydrodynamic model is applied to the confined dust cloud in a non-uniform magnetic field in order to recover the dust vortex flow driven in a conservative force field setup, in absence of any non-conservative fields or dust charge variation. Although the time independent electric and magnetic fields included in the analysis provide conservative forcing mechanisms, when the a drift based mechanism, recently observed in a dusty plasma experiment by [M. Puttscher and A. Melzer, Physics of Plasmas, 21,123704(2014)] is considered, the dust vortex flow solutions are shown to be recovered. We have examined the case where purely ambipolar electric field, generated by polarization produced by electron E*B drift, drives the dust flow. A sheared E*B drift flow is facilitated by the magnetic field gradient, driving the vortex flow in the absence of ion drag. The analytical stream-function solutions have been analyzed with varying magnetic field strength, its gradient and kinematic viscosity of the dust fluid. The effect of B field gradient is analyzed which contrasts that of E field gradient present in the plasma sheath.