A simple neutral density profile calculation for Tokamaks with  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 n 0 from a self-consistent calculation of the radial flux of neutrals Gamma , combined with the condition that div. Gamma +n 0 n 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.