Computing engineering tolerances from physics sensitivity for buildable stellarator coils

An Infinity Two high field stellarator fusion pilot plant concept and operational scenario, published in a series of papers in the Journal of Plasma Physics this year [1-7], demonstrated a plausible high field Fusion Power Plant (FPP). This FPP physics basis was designed through optimization and modelled using state-of-the-art plasma physics computational tools. In constructing an FPP, coil manufacturing and assembly processes must be chosen such that their tolerances ensure the plasma is not deleteriously altered. To this end, the sensitivity of plasma physics metrics to perturbations of the coils are analyzed in terms of the engineering tolerances. In this work, the shape gradients [8] of key transport and stability proxies are computed to inform Monte Carlo models representing different aspects of coil manufacturing and assembly. Coil tolerances for NCSX, W7X, and Infinity Two are computed to assess the feasibility of constructing and assembling coils that reproduce the desired physics in an FPP.



[1] Anderson D.T. et al. 2025 J. Plasma Phys. 91 (2), E65

[2] Hegna C.C. et al. 2025 J. Plasma Phys. 91 (3), E76

[3] Bader A. et al. 2025 J. Plasma Phys. 91 (2), E67

[4] Carbajal L. et al. 2025 J. Plasma Phys. 91 (4), E94

[5] Clark D.W.S. et al. 2025 J. Plasma Phys. 91 (3), E86

[6] Guttenfelder W. et al. 2025 J. Plasma Phys. 91 (3), E83

[7] Schmitt J.C. et al. 2025 J. Plasma Phys. 91 (3), E88

[8] Landreman M. and Paul E.J. 2018 Nucl. Fusion 58 076023