Dielectric Function and Diffusivity of Nonideal Plasmas

The dielectric function for a two-component (hydrogen) plasma at arbitrary degeneracies is considered in the entire ((kappa),(omega))-space. Collisions are treated in Born approximation leading to a ((kappa),(omega))-dependent collision integral. Two possible limits are considered: (1)(kappa)-0 (first), (omega) - 0 (second) leading to the dc conductivity a. (2) (omega)- 0 (first), (kappa)- 0 (second) leading to the diffusivity D. The relation between (sigma) and D is discussed.