On shifting the boundaries of thermodynamic instability of an asymmetric complex plasma with regard to the nonlinear screening effect

In this paper, we consider a two-component electroneutral equilibrium system of finite-sized macroions with charges $Z \ge 1$ and point oppositely charged microions with unit charges. Zones of negative compressibility and negative pressure are revealed for a wide range of macroion charges in the complex plasma phase diagram in the $\kappa$–$\Gamma$ plane $(\kappa$ is the dimensionless structural parameter and $\Gamma$ is the parameter of the Coulomb nonideality$)$. A self-similar dependence of the macroion effective charge $Z^*$ is obtained from the macroion initial charge $Z$, system temperature, and macroion sizes for fixed packing parameters with regard to a nonlinear screening effect in the Poisson–Boltzmann approxiamtion. In this study, the possibility of reaching the thermodynamic instability boundary is estimated taking into account the obtained self-similar dependence. It is shown that the thermodynamic instability boundary may become unattainable according to one of the equations of state for the complex plasma characteristic parameters.