Control of magnetic fluctuations in the reversed field pinch with edge current drive

The generation of auxiliary current in the extreme edge of the reversed field pinch is shown to affect edge and core resonant magnetic fluctuations, the recurrence time of relaxation oscillations (sawteeth), and the energy and particle confinement. Current is driven in the edge by electrostatic current sources. Although the injected current is expected to primarily affect edge resonant fluctuations, the coupling of edge and core modes enables changes in the extreme edge to have global consequences