Automating the design of tokamak experiment scenarios

The real-time control of plasma position, shape and current in a tokamak has to be ensured by a number of electrical circuits consisting of voltage suppliers and axisymmetric coils. Finding good target voltages/currents for the control systems is a very laborious, non-trivial task due to non-linear effects of plasma evolution. We introduce here an optimal control formulation to tackle this task and present in detail the main ingredients for finding numerical solutions: the finite element discretization, accurate linearizations and Sequential Quadratic Programming. Case studies for the tokamaks WEST and HL-2M highlight the flexibility and broad scope of the proposed optimal control formulation. •Self-consistent presentation of optimal control methods for scenario design for experiments with tokamaks.•Finite element methods for the discretization of the non-linear PDE-model of plasma evolution in tokamaks.•Details of SQP, the algorithm used for solving the finite dimensional constraint optimization problem.•Realistic examples and case studies that highlight feasibility, versatility and viability of the proposed approach.