Structure of Yukawa dusty plasma mixtures

Parameters characterizing the structure of a confined Yukawa system are estimated for ``dusty plasmas,'' clouds of charged macroscopic particles formed near the boundary between a plasma and the sheath, and levitated by a negatively biased electrode. When we have dust particles with different charge-to-mass ratios, they form a two-dimensional Yukawa mixture or separate two-dimensional one-component Yukawa systems, depending on the charge density in the sheath and the number density of dust particles. Pointed out is the possibility that dust particles with a larger charge-to-mass ratio have layered structures in the domain of neutral plasma, being supported by those with a smaller charge-to-mass ratio in the domain of sheath.