Approximation schemes for strongly coupled two-component plasmas

A formalism appropriate for obtaining a self-consistent handling of the strongly coupled two-component plasma problem is discussed. The divergence of the classical electron-ion pair correlation function is removed with the aid of a phenomenological ''soft-core'' potential. The important formal development is the introduction of partial linear and nonlinear polarizabilities, their interrelations, and the linear and nonlinear fluctuation-dissipation theorems satisfied by them. The formalism is used to generalize existing strongly coupled one-component plasma theories for the two-component situations. Both the schemes based on the first Bogoliubov-Born-Green-Kirkwood-Yvon (BBGKY) equation and the fluctuation-dissipation theorems, and the scheme based on the second BBGKY equation and the decomposition of the triplet correlation function are developed into self-consistent two-component equations. Algebraically, the equations appear as a set of three, coupled, nonlinear integral equations for pair correlation functions or polarizabilities