Complex Plasmas: A versatile system to study self-organization effects in strongly coupled systems on the microcanonical level

Abstract

Complex (or “dusty”) plasmas consist of electrons, ions, charged, mostly monodisperse, microparticles, and a neutral gas background. When the dust particles are brought into the plasma they immediately charge up negatively and then interact via a Yukawa-like potential whereby the mean particle separation is typically 100 times the particle size. Therefore, the microparticles become individually visible. The interaction potential is also tunable by e.g. applying additional external electric fields and may become anisotropic, which leads to further interesting effects like mode-coupling or electrorheological plasmas. The first experimental observation of the theoretically predicted plasma crystal marked the beginning of numerous research activities in complex plasma physics to investigate strongly coupled systems. In this contribution we will present recent results obtained in our laboratories on the ground and on the International Space Station (ISS) under zero gravity conditions. We will focus on (a) lane formation as a prototypical non-equilibrium phase transition in open dissipative systems, (b) synchronization of two-dimensionally oscillating plasma crystals and (c) studies of (the onset of) turbulence on the microcanonical level. It will be outlined how the application of concepts from nonlinear data analysis is often crucial for understanding and interpreting the experimental and simulated data.