Numerical Study of Structural Phase Transitions in a Vertically Confined   Plasma Crystal
  Dusty plasmas consists of an ionized gas containing small (usually negatively charged) particles. Dusty plasmas are of interest in both astrophysics and space physics as well as in research in plasma processing and nanofabrication. In this work, the formation of plasma crystals confined in an external one-dimensional parabolic potential well is simulated for a normal experimental environment employing a computer code called BOX_TREE. Such crystals are layered systems, with each layer a two dimensional lattice composed of grain particles. The number of layers is dependent upon the external potential parameter. For constant layer number, the intralayer structure transits from a square lattice to a hexagonal (triangular) lattice as the confining potential decreases. For hexagonal lattices, both hcp and fcc characteristics were found but hcp structures dominate. The relative thickness of the system was also examined. The results were compared with previous experimental and theoretical results and found to agree. 
K. Qiao and T. W. Hyde