Non-linear charge screening and interaction energy of macroions in complex plasma

Abstract

This paper analyzes the applicability range 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. The non-linear screening parameters for macroions were calculated using a direct Poisson-Boltzmann approximation. Two effects were revealed in the calculations: (i) decomposition of all microions into two subclasses, free and bound microions, and (ii) the significant reduction of the effective charge (Z*) of the initial bare macroion charge (Z) under non-linear screening by a small high-density envelope of the bound microions. We showed that the excess interaction energy is different when the non-linear screening effect is taken into account.