Experimental and theoretical investigation of mechanical disturbances in epoxy-impregnated superconducting coils. 4. Prequench cracks and frictional motion

Abstract We present an additional set of experimental results, primarily fracture events induced at transport currents below quench currents. Also presented are conductor motion events observed in test coils. The results are consistent with the results of the theoretical treatment presented in Part 2. As in Part 3, most of the results were quantified using acoustic emission data.