Plasma Beta (β) and Beta-N
The ratio of plasma pressure to magnetic pressure; higher beta means a more economical machine.
Beta is the ratio of the plasma's thermal pressure to the pressure of the confining magnetic field. It is an efficiency metric: a machine that holds more plasma pressure per tesla of field is cheaper to build. The normalised form βN removes size and field to compare configurations.
HYPERION is designed at βN = 1.532 — comfortably within the no-wall stability limits observed on spherical tokamaks such as NSTX. Its low aspect ratio is what lets it hold high beta.
Beta is the economic figure of merit for confinement: a machine that holds more plasma pressure per tesla makes more fusion power for less magnet. Spherical tokamaks excel here because their low aspect ratio raises the beta limit. HYPERION's βN = 1.532 sits comfortably below the no-wall limits observed on machines like NSTX, so it does not rely on wall or feedback stabilisation.