Energy Confinement Scaling

Confinement scalings predict how well a plasma holds energy, but spherical tokamaks follow their own trends, making extrapolation to Hyperion uncertain.

Predicting confinement

Energy confinement is summarized by empirical scaling laws fitted to data from many machines, relating confinement time to current, field, size, density, and heating power. These scalings let designers estimate performance before a machine exists. Hyperion's design point, Q_sci 3.076 at 85.0 MW, rests on confinement assumptions drawn from such scalings and from physics modeling.

The spherical-tokamak caveat

Most established scalings were built largely from conventional-aspect-ratio tokamaks. Spherical tokamaks operate in a different regime, higher beta, different field geometry, and evidence suggests their confinement can scale differently, sometimes more favorably with field. Applying a conventional scaling to a machine at aspect ratio 2.5 therefore carries real uncertainty in either direction.

Why it is stated honestly

Because gain depends directly on confinement, the confidence in Hyperion's performance is bounded by the confidence in its confinement projection. The design-and-simulation program uses ST-relevant physics models rather than a single scaling, and treats the confinement projection as a prediction to be tested, not a settled fact. Confirming it is among the primary purposes of the first-of-a-kind machine, and it is one reason no net-gain claim is made before then.

• Scalings estimate confinement from machine parameters
• ST confinement can differ from conventional scalings
• Confinement projection is a tested prediction, not a claim

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.