Transport simulation of ITER scenarios with driven burn

Transport in the ignited reduced cost ITER devices IAM (Intermediate Aspect Ratio Machine) and LAM (Low Aspect Ratio Machine) is explored by self-consistent simulations using a special version of the 1.5 dimensional BALDUR predictive transport code and applying empirical transport coefficients. The main objective of the study is to determine the thermal energy confinement time tE,r required for operation at the design parameters. It is found that the tE,r value of the inductive IAM (with a helium fraction of 9%) is 3.3 s with argon seeding compared with tE,p = 3.0 s predicted by global scalings. For operation at tE,r = tE,p the value of Q = Pfus/Pb must be reduced from 10 to 6.1, where Pfus is the fusion power and Pb is the beam power. The necessary radiative loss from closed flux surfaces is reached in the argon scenario at high and low separatrix densities. The assumption of flat density profiles and high edge densities is supported by simulations using a new scaling law for the anomalous inward drift velocity. A study of the advanced tokamak scenario of IAM resulting in an estimate of the required energy confinement time is also carried out. Simulation of the inductive LAM argon scenario yields tE,r = 4.0 s compared with tE,p = 3.9 s predicted by global scalings. Here operation at tE,p demands a Q value of 8.7.