Combined Current Profile and beta_N Control to Facilitate Accessibility and Reproducibility Testing of High-qmin Steady-State Scenarios
Division of Plasma Physics (DPP) Annual Meeting of the American Physical Society (APS)
Savannah, GA, USA, November 16-20, 2015
Abstract |
The capability of combined current profile and βN control to enable access and repeatability of steady-state scenarios for high qmin > 1.5 discharges is studied in both nonlinear simulations and experiments. The presentation focuses on model-predicted q-profile+βN control, which numerically solves successive optimal control problems over a receding time horizon by exploiting efficiently solvable quadratic programming techniques. One of the key advantages of this control approach is that it allows for explicit incorpo- ration of state/input constraints to prevent the controller from driving the plasma outside of stability/performance limits and obtain, as closely as possible, steady state conditions in the q profile. To characterize the q profile+βN response, empiri- cal correlations are combined with first-principles laws to arrive at a control-oriented model, which captures the dominant physics that is necessary for model-based optimal control design.