Ring structural transitions in strongly coupled dusty plasmas

TL;DR

This study numerically investigates how increasing potential amplitude causes dusty plasma particles to transition from a monolayer ring structure to a cylindrical shell, revealing hysteresis, symmetry, and stability properties relevant to experimental setups.

Contribution

It introduces a detailed numerical analysis of structural transitions in strongly coupled dusty plasmas confined in ring-shaped potentials, highlighting the effects of potential amplitude, curvature, and density on particle arrangements.

Findings

Transition from monolayer to cylindrical shell with increasing potential amplitude

Hysteresis observed in the transition process

Formation of multiple rings by adjusting potential curvature and density

Abstract

This paper presents a numerical study of ring structural transitions in strongly coupled dusty plasma confined in a ring-shaped (quartic) potential well with a central barrier, whose axis of symmetry is parallel to the gravitational attraction. It is observed that increasing the amplitude of the potential leads to a transition from a ring monolayer structure (rings of different diameters nested within the same plane) to a cylindrical shell structure (rings of similar diameter aligned in parallel planes). In the cylindrical shell state, the rings alignment in the vertical plane exhibits hexagonal symmetry. The ring transition is reversible, but exhibits hysteresis in the initial and final particle positions. As the critical conditions for the transitions are approached, the transitional structure states exhibit zigzag instabilities or asymmetries on the ring alignment. Furthermore, for a fixed amplitude of the quartic potential that results in a cylinder-shaped shell structure, we show that additional rings in the cylindrical shell structure can be formed by decreasing the curvature of the parabolic potential well, whose axis of symmetry is perpendicular to the gravitational force, increasing the number density, and lowering the screening parameter. Finally, we discuss the application of these findings to dusty plasma experiments with ring electrodes and weak magnetic fields.