Theory of correlation effects in dusty plasmas

Abstract

A theory of correlation effects in dusty plasmas based on a suitably augmented Debye Huckel approximation is proposed. A model which takes into account the confinement of the dust within the plasma (by external fields) is considered. The dispersion relation of compressional modes with correlation effects is obtained. Results show that strong coupling effects may be subdominant even when Г ≫ 1. Thus, in the limit Γ → 0 and/or κ → ∞, one obtains the weakly coupled dust thermal mode. In the range of values of Г ≫ 1, the strong coupling effects scale with κ instead of Г; increasing Г increases the dust acoustic waves phase velocity C_DAW in this regime. In the limit Γ≫1, κ≪1, one obtains the weakly coupled dust acoustic wave. Only in the limit Γ≫1,κ≥ 1, one obtains strong coupling effects, e.g., the dust lattice waves (κ=a/λ_d, a is the mean particle distance and λ_d is the Debye length). Observations from a number of experiments are explained.