Asymmetric complex plasma pressure and isothermal compressibility with regard to nonlinear screening in the average Wigner–Seitz cell model

The study considers a two-component electroneutral equilibrium complex plasma of finite-sized macroions with charges $Z~(Z \gg 1)$ and point oppositely charged microions with unit charges. System pressure was calculated in the Poisson–Boltzmann approximation with regard to nonlinear screening of macroions by microions in the average Wigner–Seitz cell model. One of the calculation methods obtains pressure by calculating the nonideal part of the Helmholtz free energy; the second is specific to the Wigner–Seitz average cell model. It is shown that the pressure and isothermal compressibility of the plasma are positive over the entire range of macroion concentrations.