Projected performance of ITER based on different theoretical based pedestal temperature models

Abstract

Self-consistent modeling of the ITER has been carried out using the 1.5D BALDUR integrated predictive modeling code. In these simulations, the boundary is taken to be at the top of the pedestal, where the pedestal values are described using the theory-based pedestal scalings. These pedestal temperature scalings are based on three different pedestal width models: magnetic and flow shear stabilization, flow shear stabilization, and normalized poloidal pressure. The pedestal width scalings are combined with a pedestal pressure gradient scalings based on ballooning mode limit to predict the pedestal temperature. The developed pedestal temperature scalings are used together with a core transport model, which is a combination of an anomalous transport and a neoclassical transport. An anomalous transport is calculated either using the Mixed Bohm/gyro-Bohm (Mixed B/gB) core transport model or the Multimode (MMM95) core transport model, while a neoclassical transport is computed using the NCLASS model. At the reference design point (with 40 MW auxiliary heating: 33 MW NBI and 7 MW RF), it is found that the pedestal temperatures with different pedestal width scaling ranges from 2.4 keV to 2.8 keV. As a result, the performances with the same anomalous core transport model are almost similar. It is also found that the simulations using MMM95 yield better performance than those using Mixed B/gB. In addition, when the MMM95 is used, it appears that the ion temperature gradient (ITG) and trapped electron modes (TEM) are the most dominant modes. When the Mixed B/gB is used, it appears that the Bohm contribution is the most dominated term.