Sources of acoustic emission in superconducting magnets

Origins of acoustic emission (AE) in superconducting wires have been investigated. Our experimental results indicate that wire motion is a dominant source of AE in current-carrying wires, both superconducting and nonsuperconducting. Furthermore, the results show that flux motion, except during flux jumping, produces no discernable acoustic signals. Both of these conclusions differ from the conclusions of earlier AE results which attributed the major source of AE signals in superconductors and superconducting magnets to flux motion. A simple model based on frictional sliding of conductor is presented to interpret acoustic data; agreement between theory and experiment is good.