Two-dimensional melting in a dusty plasma Available to Purchase

The melting transition has long fascinated physicists, both for its ubiquity in nature and industry and for the sophisticated physics of the phase transition in general. Two-dimensional systems can mimic surfaces, which melt differently from bulk matter. One such system is a 2D dusty plasma: Background gas in a vacuum chamber is ionized when RF power is applied to an electrode. With sufficient care, one can levitate a single layer of charged “dust” microspheres above the electrode; electrostatic repulsion spreads the particles apart, usually in a stable 2D crystalline pattern. At Ohio Northern University, Terrence Sheridan came up with a new way to heat only the layer of dust. He modulated the RF power at a resonance frequency so as to jiggle the dust up and down; some of that motional energy coupled to an in-plane acoustic instability, increasing the dusty plasma’s effective temperature. The panels show the dust distributions...