Synchronization of particle motion in compressed two-dimensional plasma crystals

TL;DR

This study uses molecular dynamics simulations to analyze how anisotropic confinement influences particle synchronization and mode-coupling instability in a 2D plasma crystal, revealing direction-dependent behaviors.

Contribution

It introduces a new order parameter to quantify synchronization and demonstrates how confinement anisotropy affects instability and collective motion in plasma crystals.

Findings

Synchronization depends on confinement orientation.

Mode-coupling instability triggers alternating oscillation chains.

Simulation results agree with experimental observations.

Abstract

The collective motion of dust particles during the mode-coupling induced melting of a two-dimensional plasma crystal is explored in molecular dynamics simulations. The crystal is compressed horizontally by an anisotropic confinement. This compression leads to an asymmetric triggering of the mode-coupling instability which is accompanied by alternating chains of in-phase and anti-phase oscillating particles. A new order parameter is proposed to quantify the synchronization with respect to different directions of the crystal. Depending on the orientation of the confinement anisotropy, mode-coupling instability and synchronized motion are observed in one or two directions. Notably, the synchronization is found to be direction-dependent. The good agreement with experiments suggests that the confinement anisotropy can be used to explain the observed synchronization process.