Neutrals and impurities in the tokamak discharges

This paper is devoted to particular and detailed studies with the Fontenay-aux-Roses one-dimensional toroidal transport code. In Section 2, the distribution of the neutrals inside the plasma and the following subsequent points are discussed: a) the correction to be added to the value of Tsub(i) obtained by analysing the spectrum of the outgoing neutrals created inside the plasma by charge exchange; b) the flux for a given energy and per unit of surface of the neutrals striking the walls. In Section 3 the influence of some parameters on the accumulation of the impurities is studied. Also the effects of the friction between two species of impurity (oxygen and molybdenum) in the case of the injection of a puff of oxygen are studied. Finally, in Section 4, sawtooth oscillations are simulated in order to attempt to shed some light on this phenomenon. (author)