Physics-model-based Actuator Trajectory Optimization and Feedback Control of the Plasma Safety Factor Profile and Internal Energy Dynamics in DIII-D

J.E. Barton, E. Schuster, M.L. Walker and D.A. Humphreys

Division of Plasma Physics (DPP) Annual Meeting of the American Physical Society (APS)

Denver, Colorado, USA, November 11-15, 2013

Abstract

Simulation and experimental results in DIII-D are presented to demonstrate the potential of integrated physics-model-based q profile and internal energy control algorithms for system- atic attainment and repeatability of discharges. Both simulations and experiments demonstrate improved profile control accuracy relative to open loop (feedforward) control alone, by using a combined feedforward + feedback scheme. The scheme is constructed by embedding a nonlinear, first-principles-driven, physics-based model of the plasma dynamics into the control design process. Firstly, a tool to numerically design actuator trajectories that steer the plasma to a desired operating state (feedforward) is developed with the objective of supporting the traditional trial-and- error experimental process of advanced scenario planning. Secondly, an algorithm to track a desired q profile and internal energy evolution (feedback) is developed with the goal of adding robustness to the control scheme.