Elongation (κ)

How vertically stretched the plasma cross-section is; taller plasmas carry more current and pressure.

Elongation κ is the ratio of the plasma's height to its width. A circular plasma has κ = 1; shaping it into a tall D raises the current it can carry and the pressure it can hold.

HYPERION is designed at κ = 2.0, a strong elongation that spherical tokamaks naturally support. Higher elongation must be balanced against vertical-stability control.