MODEL-BASED PLASMA CONTROL IN TOKAMAKS

The basic elements of an integrated model-based control strategy for extrapolating present-day advanced tokamak scenarios to steady state operation are described. Taking advantage of the large ratio between the time scales involved in the magnetic and thermal diffusion processes, the model identification procedure makes use of a multiple time scale approximation. The methodology is generic and can be applied to any device, with different sets of heating and current drive actuators, controlled variables and/or parameter profiles. It has been applied to experimental data from JET and JT-60U, and satisfactory models have been obtained. First closed loop experiments were performed on JET with three H&CD actuators to control the safety factor profile. Simultaneous real-time control of the q-profile and toroidal velocity profile on JT-60U has been simulated.