Role of electron self-interaction on heat transport in a finite-Z plasma

A nonlocal heat transport formula is derived by using nondiffusive approximation for the electron distribution function and solving the reduced Fokker-Planck equation for a moderate low-Z plasma. The gentle gradient limit of the solution yields the classical Spitzer-Haerm heat flux with the usual finite-Z correction plus a third order temperature derivative term. On the other hand in the steep gradient case, the maximum heat flow expression as well as the nonlocal propagators acquire an exponential damping factor which significantly reduces the thermal transport. The flux inhibition factor deduced from this improved nonlocal methodology is 0.04 in contrast with 0.1 of the previous nonlocal model. (orig.)