Predictive modelling of the impact of argon injection on H-mode plasmas in JET with the RITM code

Self-consistent modelling of energy and particle transport of the plasma background and impurities has been performed with the code RITM for argon seeded high density H-mode plasmas in JET The code can reproduce both the profiles in the plasma core and the structure of the edge pedestal. The impact of argon on core transport is found to be small; in particular, no significant change in confinement is observed in both experimental and modelling results. The same transport model, which has been used to reproduce density peaking in the radiative improved mode in TEXTOR, reveals a flat density profile in Ar seeded JET H-mode plasmas in agreement with the experimental observations. This behaviour is attributed to the rather flat profile of the safety factor in the bulk of H-mode discharges