Pair correlations in strongly coupled dusty plasmas

Pair correlation functions and static structure factors for dust particles are calculated in a strongly coupled plasma using the Kirkwood approximation [J. Chem. Phys. 3, 300 (1935); 14, 180 (1946)]. The kinetic integral equation is solved in long- as well as short-wavelength regimes. In the long-wavelength regime, the pair correlation function exhibits Debye-Hückel behavior and decays exponentially with distance. This type of behavior occurs not only when the dust particles are weakly coupled but also when they are unannealed and in a moderate strongly coupled regime (characterized by dust coupling constants of order unity). In the short-wavelength regime, when the characteristic spatial scale is of the order of the interdust distance, the static structure factor for strongly coupled dust particles (characterized by coupling constants much larger than unity) exhibits pronounced oscillations and liquidlike behavior, as seen in recent experiments and particle-in-cell simulations.