Effect of non-linear screening on thermodynamic properties of complex plasma

Abstract

This work is devoted to the analysis of the applicability range of a basic assumption in the phase diagram of complex plasma, i.e., linearized (Debye) screening of macroions by microions, which leads to the Yukawa form of effective interactions between macroions. Parameters of non-linear screening for macroions were calculated within the direct Poisson–Boltzmann approximation. Two effects were revealed as a result of such calculations: (i) decomposition of all microions into two subclasses, free and bound ones, and (ii) significant reduction of an effective charge Z* of the initial bare macroion Z under non-linear screening by a small high-density envelope of the bound microions. The effective charge Z* grows in the direct proportion to Z first and then, the change of Z* is negligibly thin. This renormalization of the initial Z and macroion concentration at the border of the cell leads to corresponding renormalization of initial Γ and κ into Γ* and κ* (Γ* < Γ and κ* < κ). The corresponding calculated shifts of excess internal energy are discussed and illustrated.