{'fraction_non_alphanumeric': 0.021542738012508687, 'fraction_numerical': 0.0, 'mean_word_length': 5.260869565217392, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
PTRANSP simulation and experimental test of a robust current profile and βN controller for off-axis current drive scenarios in the DIII-D tokamak

During the tokamak discharge, especially the ramp-up phase, the plasma state equilibrium continually evolves. As a consequence, the plasma response model should evolve as well. We first identified a linear plasma response model of the rotational transform ι profile and βN around a desired equilibrium. Then, an uncertainty is introduced to the identified model to partially account for the dynamic character of the plasma state equilibrium evolution. A robust controller is designed to stabilize this family of plasma models, which are reformulated into a nominal model with uncertainty. A singular value decomposition (SVD) of the nominal identified model is carried out to decouple and identify the most relevant control channels in steady-state. The DK-iteration method, combining H∞ synthesis and μ analysis, is applied to synthesize a closed-loop controller that minimizes the tracking error and input effort. The feedback controller is then augmented with an anti-windup compensator, which keeps the given profile controller well-behaved in the presence of magnitude constraints in the actuators and leaves the nominal closed-loop unmodified when no saturation is present. PTRANSP simulations and experimental results in DIII-D illustrate the performance of the model-based controller.