Structural transition of vortices to nonlinear regimes in a dusty plasma

TL;DR

This paper develops a 2D hydrodynamical model to study vortex behavior in dusty plasmas, revealing how nonlinear convection and system parameters influence flow structures transitioning from linear to nonlinear regimes.

Contribution

It introduces a detailed nonlinear analysis of dust vortex flow in a toroidal plasma system, extending previous linear models and exploring parameter effects on flow asymmetry.

Findings

Flow symmetry breaks in the nonlinear regime.

Dust flow structure is mainly affected by dissipation scales in nonlinear regime.

External driving and boundaries dominate in the linear regime.

Abstract

A 2D hydrodynamical model is developed and analyzed for the steady state of a driven-dissipative dust clouds confined in an azimuthally symmetric toroidal system which is in dynamic equilibrium with background unbounded streaming plasma. Its numerical solution not only confirms the analytical structure of the driven dust vortex flow in linear limit as reported in previous analysis, but also shows how the dust vortices are strongly affected by the nonlinear convection of the flow itself. Effects of various system parameters including external driving field and Reynolds number (Re) are investigated within the linear to nonlinear transition regime $0.001\le {\rm Re} < 50$. In agreement with various relevant experimental observations, the flow structure which is symmetric around center in the linear regime begins to turn asymmetric in the nonlinear regime. The equilibrium structure of dust flow is found to be influenced mainly by the dissipation scales due to kinematic viscosity, ion drag, and neutral collision in the nonlinear regime, whereas in the linear regime, it is mainly controlled by the external driving field and the confining boundaries.