Architecture Design and Internal Implementation of a Universal Coupling Between Controllers and Physics in a Tokamak Flight Simulator

The flight simulator predicts the dynamic behavior of a full plasma discharge (described in terms of one-dimensional profiles) by employing multiple control loops based on synthetic diagnostics, which could also emulate realistic sensor and actuator models. It serves as a valuable tool for designing and optimizing plasma scenarios, as well as for assessing the feasibility of controlling discharges. The Fenix flight simulator, originally developed for the ASDEX Upgrade, has been ported to EU-DEMO and is capable of modeling any tokamak.One of the essential elements in a flight simulator is the link between the co-simulated plasma physics and the control loops. This element is tightly coupled to the specifications of both the plasma model and the control algorithms to be implemented; but on the other hand, to ensure the portability and applicability of the flight simulator to different scenarios or devices, the coupling between plasma and control algorithms should be neutral to any concrete device and configuration. In addition, as a serial component of the control loop, data exchange takes place at every single step of the control simulation, therefore an efficient implementation is critical for the overall simulation performance. This paper summarizes the universal approach recently implemented in Fenix, which satisfies all the above requirements while remaining lightweight.