Kink Instability

A current-driven mode that bends the plasma column; bounded by the safety factor.

The kink instability bends or helically distorts the plasma column when the current is too high for the field. Keeping the edge safety factor above about 2–3 avoids the most dangerous kinks.

The kink is a current-driven mode that bends the plasma column when the current is too high for the field, and the external kink is the most dangerous ideal instability. Keeping the edge safety factor above about two, as HYPERION does, avoids it and effectively caps the plasma current for a given field.