Energy Confinement Time (τE)

How long a plasma retains its heat; longer confinement means less heating power for the same temperature.

The energy confinement time τ_E is the characteristic time over which a plasma would lose its stored energy if heating stopped. It is the single most important — and hardest to predict — performance parameter, usually estimated from empirical scaling laws.

HYPERION is designed for τ_E = 0.374 s at confinement quality H₉₈ = 1.0, i.e. it assumes standard H-mode confinement, not an optimistic multiple of it.

Because turbulence resists first-principles prediction, confinement time is estimated from empirical scaling laws fit to a large multi-machine database. HYPERION assumes only standard H-mode confinement (H₉₈ = 1.0), giving τ_E = 0.374 s — a deliberately unaggressive choice that Kronos names as a gate rather than treating as demonstrated.