The Radial Build

The layer-by-layer stack from plasma to magnet — plasma, first wall, blanket, shield, vessel, coil — that every dimension follows from.

Major radius

1.2 m

Aspect ratio

2.5

The radial build is the ordered stack of components from the plasma outward: scrape-off layer, first wall, breeding blanket, neutron shield, vacuum vessel, thermal shield, and the superconducting coil. In a compact spherical tokamak (R₀ = 1.2 m, A = 2.5) every millimetre is contested, especially at the centre column.

Fixing the radial build is one of the first design acts: it sets the machine's size, its shielding margin, and the field the magnet must deliver.