Equilibrium and non-equilibrium melting of two-dimensional plasma crystals

Abstract

Recent progress in experimental and theoretical studies of melting of two-dimensional (2D) plasma crystals is summarized. Several generic, equilibrium and non-equilibrium processes which can be observed and investigated in 2D complex plasmas are discussed, such as KTHNY, grain-boundary-induced, and shear-induced melting. Furthermore, the key features of the dominant plasma-specific mechanism of melting operating in 2D plasma crystals, the mode-coupling instability, are presented. The onset of the instability, which is characterized by threshold values of the experimental parameters, identifies the “dividing line” between the regimes when 2D complex plasmas can be employed to study generic strong-coupling phenomena, and the situations when the melting occurs due to specific processes peculiar to complex plasmas.