Garzotti, L., M. Valovic, X. Garbet, P. Mantica, V. Parail and JET EFDA contributors

Transport simulations of JET H-mode plasmas with different νeff have been performed in order to quantify the relative effect of the particle source and anomalous pinch on the gradient of the density profile. It is found that, in general, the wall ionization source and the Ware pinch velocity are not sufficient to explain the density peaking. Adding the particle source due to neutral beam injection (NBI) and an anomalous pinch proportional to D∇q/q gives results that are compatible with the experimental measurements. However, the effects of the two terms are
comparable and difficult to separate. The presence of an anomalous pinch can only be clearly identified in shots heated mainly by ion cyclotron resonance heating (ICRH) where the NBI particle source is negligible.