Resistive Wall Mode (RWM)

The RWM is a slow-growing instability at high beta that the conducting wall only partly suppresses. Kronos holds it with active feedback.

What

A kink instability slowed by the conducting wall

When

Above the no-wall beta limit

Kronos control

Active RWM feedback with rotation + kinetic effects

Enables

Operating near β_N = 4.33 and toward wall-stabilized 5.0

The resistive wall mode (RWM) is a magnetohydrodynamic instability that appears when a tokamak runs above its "no-wall" beta limit. A perfectly conducting wall would stabilize it completely; a real, resistive wall only slows it, so it grows on the wall's timescale — slow enough to catch, but only with active control.

Controlling the RWM is what lets Kronos MetroVolt operate at high normalized beta (β_N = 4.33) and reach toward the wall-stabilized β_N = 5.0 that unlocks additional fusion power. The design uses an active feedback system informed by plasma rotation and kinetic effects, and the wall-stabilized limit is exactly what the deposited stability analyses adjudicate.