Collision operator including large-angle scattering for moderately coupled plasma

A new approach has been developed to treat the large-angle as well as the small-angle binary collisions in high temperature and high density plasmas when the test particle distribution function fαfα is even function about the test velocity ν⇀α and the relations of the mass and the velocity between the test particles and the field particles are satisfied with mα≪mβmα≪mβ (such as electron–ion collision or Lorentz-gas model) and |ν⇀α|≫|ν⇀β|. With the approach, the Boltzmann collision operator is derived to be suitable for the plasma considered as weakly coupled (Coulomb logarithm lnΛ≥10) and moderately coupled (2≤lnΛ≤10), i.e., for the electron–ion coupling constant Γei<0.1Γei<0.1. The modified collision operator has a direct and practical connection to the Rosenbluth potentials, the new reduced electron–ion collision operator differs from the original Fokker–Planck operator for Coulomb collisions by terms of order 1/lnΛ. Moreover, some calculations of relaxation rate and transport properties are given for new reduced electron–ion collision operator that shows 0.153/lnΛ corrections.