Structural analysis of a Coulomb lattice in a dusty plasma.

Pair and bond-orientational correlation functions and structure factors, asused in colloidal science, are applied as quantitative indicators of the phase of the newly discovered "plasma crystals." These Coulomblattice structures are formed by charged microspheres levitated in glow discharge plasmas and are imaged photographically. Static structural analysis is demonstrated on the experimental data of Thomas et al. [Phys. Rev. Lett. 73, 652, {1994)) and interpreted in the context of a two-dimensional (2D) dislocation-unbinding melting theory and a 2D density-wave melting theory.