CC BY
14COMPLEX PLASMAS
PHASE TRANSITIONS IN SMALL CHARGED DUST SYSTEM
O.F. Petrov1,2
Joint Institute for High Temperatures RAS, Moscow, Russia 2Moscow Institute of Physics and Technology, Dolgoprudny, Russia
The charged dust system represent a non-neutral or quasi-neutral systems (dusty plasmas) containing micron-sized particles of a substance with electrical charges
up to 102-105e. As a result of strong interaction, the dust particles may form the ordered structures of liquid and crystal types. The laboratory dusty plasma is the unique object for studying the structures, phase transitions and transport phenomena on the "kinetic level".
Within the framework of the presented work we studied a nature of phase transition in quasi-two-dimensional (quasi-2D) dusty plasma clusters and investigated the influence of the quasi-2D cluster size (a number of particles in it) on the features of the phase transition. Experiments and numerical simulation was conducted for the systems consisting of small (~10...103) number of particles. To estimate the phase state of the system with 7, 18 and 100 particles observed in numerical and laboratory experiments, we used the method based on analysis of dynamic entropy. Phase state of systems with the number of elements in the order
of 103, was estimated using the methods of statistical thermodynamics. Here we present new results of an experimental study of the change of translational and orientational order and topological defects, the entropy and the pair interactions at 2D melting of dust cluster in rf discharge plasma. Numerical modeling of small systems was conducted by the Langevin molecular dynamic method with the Langevin force, responsible for the stochastic nature of the motion of particles with a given kinetic temperature. Calculations were performed for two-dimensional systems with the Yukawa potential of interparticle interaction.
This work was supported by the Russian Scientific Foundation Grant No. 14-1201440.
