RFP energy evolution and containment in the presence of giant sawteeth

Experimental measurements of internal energy in the ZT-40M Reversed Field Pinch are presented that reinforce the interpretation of the soft x-ray sawtooth oscillations seen in that device as indicating an internal energy loss. Soft x-ray spectra are presented that support the contention that hot electron confinement, as well as energy confinement, is severely degraded by the presence of large scale sawteeth, presumably during the fall time of the soft x-ray flux. The behavior of the equilibrium fields may be explained as the result of a combination of current redistribution and a decrease and recovery in internal βp during a sawtooth.