Polycrystalline structure of dust formations formed in striations in glow discharge

Our experiments provided structures consisting of more than 6000 particles for investigations; its horizontal section contained more than 400 particles. Primitive visual observation indicates 2D section areas with higher ordered arrangement of particles. Such areas are quantitatively identified by means of local orientation function, which was built without section averaging. The structure´s mapping of orientational ordering was performed. The domains with better orientation ordering are easily distinguished on the map. Pair correlation and orientation correlation functions built for the largest domain show that, in agreement with KTHNY-theory, the crystalline state exists in that domain. The overall 2D section appears to be in liquid-like state. The received result indicates at analogy between dusty plasma ordered structures and crystal structure in usual substance.