Nonlinear regime of the mode-coupling instability in 2D plasma crystals

¹ Max Planck Institute for Extraterrestrial Physics - 85741 Garching, Germany
² CNRS, Aix-Marseille-Université, Laboratoire de Physique des Interactions Ioniques et Moléculaires 13397 Marseille Cedex 20, France

^(a) tbr@mpe.mpg.de

Received: 24 February 2014
Accepted: 1 May 2014

Abstract

The transition between linear and nonlinear regimes of the mode-coupling instability (MCI) operating in a monolayer plasma crystal is studied. The mode coupling is triggered at the centre of the crystal and a melting front is formed, which travels through the crystal. At the nonlinear stage, the mode coupling results in synchronisation of the particle motion and the kinetic temperature of the particles grows exponentially. After melting of the crystalline structure, the mean kinetic energy of the particles continued to grow further, preventing recrystallisation of the melted phase. The anomalous kinetic temperature obtained in the experiments could not be reproduced in simulations employing a simple point-like wake model. This shows that at the nonlinear stage of the MCI a more careful analysis is necessary.