Simultaneous Electron Temperature and Safety Factor Profile Control for DIII-D

A robust control scheme has been developed to simultaneously control the electron temperature (T_e) and safety factor (q) profiles on DIII-D.  Control of both kinetic and magnetic profiles is crucial to improve plasma performance and maintain magneto-hydrodynamic stability in tokamak plasmas.  Because of this, techniques to simultaneously control multiple profiles need to be developed.  The dynamics of these profiles can be described by coupled nonlinear parabolic partial differential equations.  The plasma resistivity is modeled as an uncertainty, and robust control techniques are used to design a controller that is capable of tracking prescribed profiles for an expected range of uncertainty.  The controller is then tested in closed-loop simulations by using the Control Oriented Transport Simulator (COTSIM).  Preliminary predictive simulation results show that this controller is indeed capable of regulating both the electron temperature and the safety factor profiles with acceptable dynamic performance and robustness.

*Supported by the US DOE (DE-SC0010661, DE-FC02-04ER54698) and by the NSF GRFP (1842163).