Ion-Streaming Induced Order Transition in 3D Dust Clusters

TL;DR

This study uses dust dynamics simulations to explore how ion streaming influences the structure of 3D dusty plasma clusters, revealing a transition from crystalline shells to flow-aligned chains and identifying a critical ion drift velocity causing melting.

Contribution

The paper introduces a dynamical screening simulation approach to model ion streaming effects on 3D dust clusters, demonstrating a novel order transition and the impact of ion drift velocity.

Findings

Yukawa balls destabilize at M≈0.1

Flow-aligned chains form at M≥1

Transition is discontinuous and size-independent

Abstract

Dust Dynamics Simulations utilizing a dynamical screening approach are performed to study the effect of ion-streaming on the self-organized structures in a three-dimensional spherically confined complex (dusty) plasma. Varying the Mach number M - the ratio of ion drift velocity to the sound velocity, the simulations reproduce the experimentally observed cluster configurations in the two limiting cases: at M=0 strongly correlated crystalline structures consisting of nested spherical shells (Yukawa balls) and, for M\geq1, flow-aligned dust chains, respectively. In addition, our simulations reveal a discontinuous transition between these two limits. It is found that already a moderate ion drift velocity (M\approx0.1) destabilizes the highly ordered Yukawa balls and initiates an abrupt melting transition. The critical value of M is found to be independent of the cluster size.