Kinetic theory of binary correlations in turbulent plasmas

The two-particle correlations in a turbulent plasma are analyzed on a quite general basis by using the modern methods of non-equilibrium statistical mechanics. It is shown that the binary correlations can be split (in a time in- variant way) into a part which decays quickly by ballistic motion, and a long- living part: ‘the natural correlations’. The latter are continuously regenerated from the one-particle distribution function by the internal interactions, even in the absence of true collisions. The general theory can be made operational by using approximation schemes, among which the ‘RQL2’ method, which generalizes the renormalized quasi-linear approximation, leads to results comparable to, but more general than, those developed by previous authors. The explicit relation of the long-living enhanced correlations to the concept of ‘clumps’ will be developed in a forthcoming paper.