Structures and dynamics of dusty plasmas and dusty plasma mixtures

Dusty plasmas can be regarded as assemblies of Yukawa particles in a one-dimensional potential well. We extend the analyses on dusty plasmas in two directions: the two-dimensional Yukawa system and Yukawa mixtures. (1) Under appropriate conditions at low temperatures, dust particles sit in a plane which is perpendicular to the gravitational field. When they are also confined laterally by an electrode, we have a finite two-dimensional system of Yukawa particles. The low temperature structures are obtained by molecular dynamics simulations and the results are reproduced by theoretical analyses. Through these analyses we show that the correlation energy of the Yukawa system plays an essential role in structure formations. As for dynamics of this system, a crossover from the surface freezing of Coulomb system to surface melting of systems of short-ranged interactions is observed. (2) In the case of mixtures, we have an extra parameter characterizing the difference in the gravity on each species. We obtain the low temperature structures of this system and compare them with theoretical predictions based on the results for the case of one component.