A simple neutral density profile calculation for Tokamaks with λ_mfp<<a

A simple and expeditious technique is developed for calculating the neutral density profile in the dense region of large Tokamak plasmas, where lambda _mfp<<a. The method rests on determining the local logarithmic derivative of n₀ from a self-consistent calculation of the radial flux of neutrals Gamma , combined with the condition that div. Gamma +n ₀n_e( sigma nu )_ei=0. The results from this simple technique are compared with a more time-consuming Monte-Carlo calculation, and good agreement is found.