Crystallization of a three-dimensional complex plasma under laboratory conditions

The influence of neutral gas pressure for crystallization of cylindrical complex plasmas under laboratory conditions is investigated. For the analysis of the complex plasma structure, different methods are adopted: First, the pair correlation and a criterion based on the shape of the Voronoi cells are applied. Besides this, a new implementation, which connects the Minkowski structure metric with the benefits from the scalar product of the local bond order parameter, is presented. In addition, the bcc sensitive Minkowski structure metric is used to identify the crystalline structures. All criteria display the same behavior: Decreasing the neutral pressure leads to crystallization. This is the opposite behavior to that observed in former ground based experiments. Published by AIP Publishing.