The keys to the management of time-evolution signals on HDF5 files in ITER

ITER (International Thermonuclear Experimental Reactor) is the largest international experiment in the field of generating nuclear‑fusion energy by magnetic confinement. ITER’s objective is to operate in modes that come as close as possible to the conditions of a commercial fusion reactor, which implies long pulses and systems running continuously. From the point of view of the data acquisition and control system, ITER, on the one hand, requires an enormous number of signals (due to its size and experimental nature), many of them with a very high sampling rate (due to the highly chaotic nature of the plasma under extreme conditions), and, on the other hand, it requires a data storage and management system compatible with long pulse and continuous data acquisition. These requirements have driven the design and implementation of ITER’s data‑storage and management system, where time‑evolving signals and their real‑time processing have absorbed the great majority of development effort. From the very beginning, ITER chose HDF5. This presentation describes the technical factors that have proved decisive in using HDF5 as the core technology for storing and managing all of ITER’s time‑evolving signals, as well as for the real‑time handling of their data. It details the different challenges that have been addressed throughout the project, together with a detailed description of the solutions that have been adopted at the design and implementation level.