Description
This work benchmarks different reconstruction methods for disruption-induced EM forces [1], using experimental data from the COMPASS tokamak [2]. Two approaches are compared: a direct diagnostic approach enabled by the excellent magnetic diagnostics coverage of COMPASS, and a magnetic source decoupling approach, applicable in more general contexts and adaptable to detailed component studies. Within the latter approach, the recently proposed method based on current centroid tracking [3] is compared with a novel integral equation method, based on a widely known decoupling theorem for the poloidal flux [4]. This is applied at a diagnostics surface enclosing the plasma, conveniently discretizing the surface integrals and appropriately solving the singularities appearing in the integral formulation. The proposed method is shown to provide more accurate magnetic field decoupling than the current-centroid tracking method. Finally, the integral equation method is compared against the direct measurement approach possible in COMPASS, both for a downward and an upward disruption scenario. The results presented highlight the potential of the proposed method for developing accurate electromagnetic force reconstruction algorithms in present-day and future devices.
[1] I. Bandyopadhyay, Nuclear Fusion, vol. 65 (10), pp. 103001 (2025)
[2] M. Hron, et al. Nuclear Fusion, vol. 62 (4), pp. 042021 (2022)
[3] F. Villone, et al. Nuclear Fusion, vol. 66 (1), pp.016030 (2026)
[4] B. J. Braams, Plasma Physics and Controlled Fusion, vol. 33 (7), pp.715-748 (1991)
Acknowledgments
This work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No 101052200 — EUROfusion). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the European Commission can be held responsible for them. The work was performed on the Large Reserch Infrastructure COMPASS, code 90245, which operation was funded by MEYS project LM2023045. The authors are grateful to the ERASMUS Mundus Fusion Engineering and Physics M.Sc. programme, which allowed to start the collaboration on this research topic.