100 Noninductive Operation At High Beta Using Off Axis Eccd

The Advanced Tokamak (AT) program on DIII-D is developing the scientific basis for steady-state, high-performance operation in future devices. The key element of the program is to demonstrate sustainment of 100% noninductive current for several seconds at high beta. Guided by integrated modeling, recent experiments using up to 2.5 MW of off-axis electron cyclotron current drive (ECCD) and up to 15 MW neutral beam injection (NBI) with q[sub 95] [approx] 5 have sustained [approx] 100% of the plasma current noninductively for 1 s at high beta ([beta] [approx] 3.6%, [beta][sub N] [approx] 3.4, above the no-wall limit) with q[sub min] [ge] 1.5 and good confinement (H[sub 89] [approx] 2.3). Integrated modeling using both empirical and theory-based models is used to design experiments and to interpret their results. These experiments have achieved the parameters required for the ITER Q=5 steady-state scenario, and the same modeling tools are applied to ITER AT scenario development.