Plasma performance optimization in ASDEX upgrade

The International Thermonuclear Experimental Reactor (ITER) must run near operational limits to produce high-performance plasmas that, beyond position and shape control, rely on optimized control of additional plasma parameters. Control of single parameters, such as beta, plasma stored energy, or ion cyclotron resonance heating antenna coupling, has already been reported. Further performance improvements can be achieved by coordinated control of combinations of parameters. These may be specific to the different phases of a discharge, e.g., for radiative boundary concepts. A growing understanding of discharge behavior will lead to the identification of better control scenarios involving both new parameters and control methods. This requires a universal platform into which control algorithms can flexibly be integrated to adapt to interesting discharge scenarios. With the multitude of processes expected to be implemented, management of real-time processes becomes crucial. This paper explains how this issue is raised by the requirement specification of the controller and how it influences design, implementation, and operation of the plasma performance controller. Examples such as the achievement of completely detached H-mode plasmas demonstrate the working method and its effectiveness.