Externally induced rotation of the resistive wall modes in RFX-mod

This paper reports on the active rotation experiments in RFX-mod where it is demonstrated for the first time in reversed field pinches that an internal non-resonant resistive wall mode can be 'unlocked' from the resistive wall using an external perturbation. The observed constant rotation of the mode depends on the phase shift between the external perturbation and the mode. It is seen that plasma rotation, plasma current and coupling to other modes have no impact on the rotation frequency of the mode. A simple analytical model is proposed which gives a good description of the experimental results.