Controlling a New Plasma Regime
Success of UKs STEP (Spherical Tokamak for Energy Production) programme [1] [2] [3] [4] requires a robust plasma control system. This system has to guide the plasma from initiation to the burning phase, maintain it there, producing the desired fusion power for the desired duration and then terminate the plasma safely. This has to be done in a challenging environment with limited sensors and without overloading plasma facing components. The plasma regime in STEP will be self-organising adding further complications to the plasma control system design. This article describes the work to date on the design of individual controllers for plasma shape and position, magneto hydrodynamic modes, heat load and fusion power. Having studied \\’normal\\’ operation, the paper discusses the philosophy of how the system will handle exceptions, when things don\\’t go exactly as planned.