Negative Triangularity in Depth

Why Kronos points the plasma's corners the 'wrong' way — and what it buys.

Triangularity

-0.30

Benefit

ELM suppression + good confinement

Conventional D-shaped plasmas use positive triangularity; HYPERION uses negative triangularity (δ = -0.30). Recent experiments show negative-δ plasmas can access good confinement while naturally suppressing edge-localised modes, easing the divertor's life without an active ELM-control system.

It is a deliberate, physics-based stability choice, not a cosmetic one.