Speaker
Christopher James Rapson
(Max Planck Institute for Plasma Physics)
Description
Integrated control of many plasma parameters simultaneously is expected to increase the reproducibility and stability of scenarios, which are otherwise developed laboriously through trial and error. The benefits are expected to be especially important for high performance scenarios, operating near multiple stability boundaries. The two main challenges of integrated control are: firstly the physics coupling between parameters, which is often non-linear and regime-dependent. Secondly, fusion experiments operate with a limited set of actuators which restricts the set of parameters that can be simultaneously controlled. Furthermore, one actuator can affect several parameters and/or several actuators can affect the same parameter. To satisfy conflicting requirements on actuators, some form of actuator management is required.
For the specific case of actuator management for ECRH, a routine has been developed at ASDEX Upgrade which optimally allocates four gyrotrons to central heating (to avoid tungsten accumulation), mitigation of 3/2 Neoclassical Tearing Modes (NTMs) and mitigation of 2/1 NTMs. The allocation occurs in real-time, reacting to changing plasma conditions and actuator availability during an experiment. In future this could be extended to more gyrotrons and targets such as sawtooth control, electron temperature profile control and current profile control.
Experiments will show the flexibility of this algorithm to operate in a range of scenarios and in combination with other controllers for beta, radiation, edge density using gas puffing and core density using a new pellet feedback controller. The controllers operate in parallel, and hence integration will be limited to co-ordination of their reference trajectories by a high level supervisory controller. This contribution will present observations on the coupling between controllers, and a design for a truly integrated MIMO controller to be developed for the next MST1 campaign.
Co-authors
Bernhard Ploeckl
(Max Planck Institute for Plasma Physics, Garching, Germany)
Bert Maljaars
(Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, Netherlands)
Christopher James Rapson
(Max Planck Institute for Plasma Physics, Garching, Germany)
Cristian Galperti
(École Fédérale Polytechnique de Lausanne (EPFL), Swiss Plasma Center (SPC), Lausanne, Switzerland)
Federico Felici
(Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, Netherlands)
Joerg Stober
(Max Planck Institute for Plasma Physics, Garching, Germany)
Marc Maraschek
(Max Planck Institute for Plasma Physics, Garching, Germany)
Matthias Reich
(Max Planck Institute for Plasma Physics, Garching, Germany)
Morten Lennholm
(CCFE, Culham Science Centre, Abingdon, OX14 3DB, United Kingdom)
Olivier Sauter
(École Fédérale Polytechnique de Lausanne (EPFL), Swiss Plasma Center (SPC), Lausanne, Switzerland)
Peter Lang
(Max Planck Institute for Plasma Physics, Garching, Germany)
Wolfgang Treutterer
(Max Planck Institute for Plasma Physics, Garching, Germany)
the ASDEX Upgrade Team
(Max Planck Institute for Plasma Physics, Garching, Germany)
the EUROfusion MST1 Team
(Max Planck Institute for Plasma Physics, Garching, Germany)
