Compact Major Radius R0 1.2 m

R0 1.2 m keeps Hyperion small; combined with A 2.5 it fixes the plasma volume and, with the field, the fusion power.

Why 1.2 metres

The major radius R0 is the distance from the central axis of the machine to the center of the plasma cross-section. At 1.2 m Hyperion is a compact device. Together with aspect ratio A 2.5 this sets the minor radius near 0.48 m and fixes the plasma volume that produces the 85.0 MW of fusion power.

Small R0 is a deliberate foundry choice. A smaller machine is faster and more tractable to build, retires physics risk on less hardware, and concentrates the neutron flux — useful when the neutron itself is the product. It also raises the on-axis field for a given center-post current, feeding the high-field, high-beta operating point.

The compactness penalty

Everything is closer to the plasma at small R0: heat, neutrons, and stress all land on less material. Inboard shielding is thin, and the center post lives in a hard radiation environment with a limited lifetime. Compactness is the source of both the machine's advantage and its most demanding engineering. The design does not treat 1.2 m as a free parameter to shrink further; it is held at the smallest value consistent with routing the toroidal-field conductor, leaving room for a workable blanket over most of the plasma, and keeping the center post's lifetime within a plannable replacement schedule.

• R0 1.2 m with A 2.5 → minor radius near 0.48 m
• Compact build, concentrated neutron flux
• Penalty: thin inboard shielding, life-limited center post

This page describes a design-and-simulation study, not a built machine. Construction begins Q2 2027; first-of-a-kind first tritium is targeted near 2030. No hardware net-gain is claimed before FOAK.