Perturbation approach to the classical one-component plasma

The two-particle correlation function for the classical one-component plasma in the high-density fluid phase is calculated from the correlation function of a short-range reference potential by a perturbation method based on the hypernetted chain equation (HNC). It is shown th\`at the long-wavelength correlations are correctly described by this method. A technique for extending $g(r)$ to infinity is shown to be valid and useful. The results are in excellent agreement with those obtained from the "Ewald image" Monte Carlo method.