Analysis and Simulation of ITER Steady-State Discharges on DIII-D

One of the primary goals of the ITER project is to demonstrate a reactor scale steady-state operation for future tokamaks. This is a challenging task which requires simultaneous operation with fully noninductive current drive, a fusion gain of $Q\geq 5$ and IBS for discharges approximately 3000s in length. Previously, DIII-D has demonstrated fully noninductive scenario in ITER-like shaped plasmas at relatively high $q_{95}\sim 6.5$ and moderate $\beta_N\sim 3$ but with low fusion performance ($G=\beta_N H_{89}/q_{95}^2\sim 0.15$). Recent high $q_{min}$ experiment and modeling indicate that the goal of $G=0.3$ predicted for $Q=5$ operation on ITER can be achieved noninductively at reduced $q_{95}$ and at higher $\beta_N$. An optimum choice of $q_{95}$ and $\beta_N$ for the ITER steady-state mission will be discussed based on the experimental scaling from ITER demonstration discharges on DIII-D, as well as predictive FASTRAN scenario modeling using TGLF coupled to the Integrated Plasma Simulator. FASTRAN is a new iterative numerical procedure that integrates a variety of models (transport, heating, CD, equilibrium and stability) and has been shown to reproduce most features of DIII-D high beta discharges with a stationary current profile.