  We present a parametrization of the pair correlation function and the static
structure factor of the Coulomb one component plasma (OCP) from the weakly
coupled regime to the strongly coupled regime. Recent experiments strongly
suggest that the OCP model can play the role of a reference system for warm
dense matter. It can provide the ionic static structure factor that is
necessary to interpret the x-ray Thomson scattering measurements, for instance.
We illustrate this with the interpretation of a x-ray diffraction spectrum
recently measured, using a Bayesian method that requires many evaluations of
the static structure factor to automatically calibrate the parameters. For
strongly coupled dusty plasmas, the proposed parametrization of the Coulomb OCP
pair correlation function can be related to the Yukawa one, including
screening. Further prospects to parametrize the static structure of Yukawa
systems are also discussed.
