Abstract. Control of MHD mode dynamics is essential to improving the reversed field pinch (RFP) experiments as a part of the fusion research programs. The STE-2 RFP has been operated only with a vacuum vessel ( 0.15ms) to test the idea of driving MHD mode and/or plasma rotation by using resonant rotating helical field (RHF) which is applied from outside of the vessel. We report new results which indicate direct interaction between the RHF and inherent tearing modes. Without the RHF, the magnetic disturbance outside the vessel is dominated by almost locked m/n=1/8 core resonant tearing modes, growing with the scale of vessel time constant. The RHF tends to drive the mode rotation with a transient suppression of the mode growth. Improved RFP performance has not become clear yet. Stabilization of the external kink modes will also be discussed.
IAEA 2001