170. OPTIMAL CONTROL TECHNIQUES FOR RESISTIVE WALL MODES IN TOKAMAKS
Name: Mitchell Dobbs Pears Clement
Grad Year: 2017
Tokamaks, machines designed to heat and confine plasma for producing fusion energy, can excite Resistive Wall Modes (RWMs), which are strong, locked or nearly locked kink modes whose rotation frequencies do not evolve quickly and are slow compared to their growth rates. Simulations have predicted that modern control techniques like Linear Quadratic Gaussian (LQG) control will perform better than classical control techniques when using control coils external to the tokamak vacuum vessel. An LQG control algorithm based on the VALEN model for the RWM, and running on a Graphics Processing Unit (GPU) platform, has been developed and tested on the DIII-D tokamak at General Atomics in San Diego, CA. Experiments have shown the algorithm is able to track and suppress with external control coils the plasma response of a rotating n=1 perturbation driven by internal control coils by 32%. Tokamaks designed to operate as real fusion reactors, such as the International Thermonuclear Experimental Reactor (ITER) will likely have to stabilize the RWM using control coils external to its vacuum vessel.
Industry Application Area(s)
Control Systems | Energy/Clean technology