Coil design for the Infinity Two fusion pilot plant

Type One Energy is currently designing its InfinityTwo Fusion Power Plant (FPP), a high field stellarator with High Temperature Superconducting (HTS) magnets, building on the experience and insights gained from the physics basis configuration we recently published [1-7]. We present key aspects of our coil design methodology and of the resulting coil sets for the InfinityTwo FPP. Specifically, we emphasize the importance of accounting, during coil design, for finite coil pack effects as well as the ferromagnetic properties of the structures and blanket, and of minimizing the sensitivity of the reactor performance to perturbations of the coil geometry. We demonstrate the ability to control via external coils the width of the edge islands needed for our resonant divertor strategy, in order to maximize radial space for the blanket and shield and maximize the lifetime of coils, without penalizing core performance. Finally, we highlight desirable features of our optimized coil sets, such as the low curvatures of our coils and the low maximum magnetic field within the coil packs, which lower the cost and complexity of coil manufacturing.

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

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

[4] L. Carbajal et al., J. Plasma Phys. 2025, 91 (3), E94

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

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

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