Crystallization of a Complex Plasma Under Gravity Conditions in Dependence of Pressure

The crystallization of a 3-D complex plasma under gravity conditions at different gas pressures is investigated. Three different methods are applied to determine the phase state of the complex plasma: the pair correlation, the nonspherical distribution (which uses the geometric properties of the Voronoi cells of each particle), and an improvement of the scalar product of the local bond-order parameter (SPBOP). All criteria are in accordance with that the complex plasma is in solid at low and in liquid state at high pressure.