Observation of a new toroidally localized kink mode and its role in reverse-fieldpinch plasmas

Abstract
A new type of toroidally localized kink instability, which we named the ‘‘slinky mode,’’ was observed in a reversed-fieldpinch plasma in the OHTE (Ohmic heating toroidal experiment) device. It is found that the slinky mode is the result of the phase locking of several internal kink modes due to nonlinear coupling and is an effective way to approach the Taylor relaxed state.