Third-order connection between the collision source chi(v,μ) and the isotropic component f0 of the usual distribution function f(v,μ) for electrons in a weakly ionized gas

By virtue of the conclusions of the preceding companion paper, the collision source chi(v,μ) (representing the density of particles entering the velocity space around v = (v,μ)) is expressed as an explicit function of the isotropic component f0(v) of the usual distribution function f(v,μ) with third-order accuracy in the acceleration a. Also the components f1(v), f2(v) and f3(v) are explicitly given as functions of f0 with third-order consistency. The last achievement paves the way to the following companion papers. (author)