Plasma Profile and Shape Optimization for the Advanced Tokamak Power Plant, ARIES-AT
Authors: C.E. Kessel, S.C. Jardin, T.K. Mau, and F. Najmabadi
Date of PPPL Report: June 2001
Published in: Fusion Engineering and Design 80 (2006) 63–77.
An advanced tokamak plasma configuration is developed based on equilibrium, ideal-MHD stability, bootstrap current analysis, vertical stability and control, and poloidal-field coil analysis. The plasma boundaries used in the analysis are forced to coincide with the 99% flux surface from the free-boundary equilibrium. Using an accurate bootstrap current model and external current-drive profiles from ray-tracing calculations in combination with optimized pressure profiles, bN values above 7.0 have been obtained. The minimum current drive requirement is found to lie at a lower bN of 5.4. The external kink mode is stabilized by a tungsten shell located at 0.33 times the minor radius and a feedback system. Plasma shape optimization has led to an elongation of 2.2 and triangularity of 0.9 at the separatrix. Vertical stability could be achieved by a combination of tungsten shells located at 0.33 times the minor radius and feedback control coils located behind the shield. The poloidal-field coils were optimized in location and current, providing a maximum coil current of 8.6 MA. These developments have led to a simultaneous reduction in the power plant major radius and toroidal field.