Sawtooth Oscillations

Periodic core temperature crashes from a central instability; usually benign but can trigger other modes.

Sawteeth are repetitive collapses of the plasma core temperature caused by an internal kink and reconnection. Usually tolerable, they can seed larger neoclassical tearing modes, so they are managed.

Sawteeth are repetitive core temperature collapses driven by an internal kink and magnetic reconnection when the central safety factor drops below one. Usually tolerable on their own, they can seed the larger neoclassical tearing modes that limit performance, so they are actively managed with heating and current drive.