Influence of particle sources on electron density peaking in TCV and JET

Abstract

Calculations of the particle flux caused by neutrals originating from the edge are performed for TCV and JET using the one-dimensional kinetic transport code Kn1D. The analysis, confirmed by experimental evidence, shows that for TCV and JET edge fuelling as well as neutral beam fuelling cannot be responsible for the density gradient in the plasma bulk, confirming the presence of inward particle convection. The results corroborate the expectation of a peaked density profile in ITER, despite the lack of bulk particle fuelling.