Simulation and data processing techniques to design optimized PPR systems on plasma fusion devices

Abstract

Plasma position reflectometry (PPR) will be used for measuring the plasma position and shape in DEMO. To ensure the reliability, PPR systems are optimized for the expected range of plasmas foreseen during the operation. The study and optimization of PPR systems is a highly demanding computational task and the current approach to define the simulation setup and process the simulation results is time-consuming and does not allow the study of a large number of configurations in useful time.In this article we automate the simulation process required for studying and optimizing PPR systems with the REFMUL family of full-wave FDTD codes. A general overview of the fundamental concepts of PPR systems is presented in the context of reflectometry simulations. Different solutions are proposed to produce realistic reflectometer models from CAD files, realistic plasma models, minimize the complexity of the input definition, manage the simulations in HPCs and analyze the simulation results of PPR systems. A new algorithm based in the In-phase and Quadrature (I/Q) detection scheme is developed to extract the phase derivative and the detected signal amplitude from the synthetic signals of a generic simulation. These techniques allow a brute-force approach to reflectometry problems, being essential for the study of reflectometry systems. The algorithms are validated using the 2017 DEMO baseline scenario to test more than 100 different reflectometers at different poloidal positions in the same toroidal section. The application of our methodology can be extended to different reflectometry techniques and other fields.