Kinetic and magnetic control of fusion power fluctuations in EU-DEMO

Plasma heating during the burn phase of the European demonstration reactor EU-DEMO will be determined by fusion-generated alpha particles. This occurrence leads to control issues which are absent in present tokamaks, where plasma heating is driven without any feedback from the plasma on the heating itself. Currently, a so-called “tokamak flight simulator” is being developed in EUROfusion, with the purpose of simulating all dynamic phases of the EU-DEMO operation. In particular, the 1.5D transport code ASTRA, which models the plasma and its magnetic equilibrium, has been coupled to the commercial control environment Simulink. This model has then been equipped with magnetic control blocks developed with the code CREATE-NL. The resulting tool models the action of kinetic and magnetic actuators, as well as the corresponding plasma dynamic response, in a self-consistent way. In this work, the code is employed to investigate the control strategy to counteract fusion power fluctuations during burn phase in EU-DEMO, which could lead to major operational issues if uncontrolled. The considered actuators are H&CD auxiliaries, mass injection systems and plasma shape and position control coils. Their interplay is investigated, towards the definition of a control strategy for the burn phase.