Confinement Time and Triple Product
The fusion triple product n·T·tau_E must exceed a threshold for gain; it is the single figure that ties density, temperature, and confinement together.
One number for gain
Fusion performance is captured compactly by the triple product: plasma density n, temperature T, and energy confinement time tau_E multiplied together. Reaching a target gain means exceeding a threshold value of this product. It is the most honest single summary of how close a plasma is to useful operation, because it forces all three quantities to be stated at once.
Hyperion's Q_sci 3.076 corresponds to a specific triple-product target. Any one factor can be traded against the others: higher density can offset shorter confinement, hotter plasma can offset lower density, within limits set by stability and by the fusion cross-section's temperature dependence.
Where the pressure comes on
Density and temperature together are just plasma pressure, capped by the beta limit; confinement time is capped by transport and set by the empirical scalings. So the triple-product target is simultaneously a beta problem and a confinement problem. Hitting it at R0 1.2 m and 8 T on-axis is the design-and-simulation claim that the confinement gate exists to check. Because the three factors are not independent — density is bounded by the density limit, temperature by the fusion cross-section and heating, and confinement by transport — the target cannot be reached by pushing any single factor; it demands a balanced operating point where all three sit comfortably within their own limits at once.
- Gain requires n·T·tau_E above a threshold
- Factors trade off within stability and cross-section limits
- The target couples the beta limit and the confinement scaling
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.