Highly time-resolved measurement of quench inception and propagation in ac superconducting wires

In this paper, highly time-resolved and highly sensitive measurements of quench phenomena in ac superconducting wires enabled us to investigate the propagation characteristics of normal zone at the quench inception. Experimental results revealed that the transient propagation velocity of normal zone reached 90 km/sec at 6 /spl mu/sec after the quench-onset of the non-insulated NbTi/CuNi superconducting wires. Furthermore, there could exist an intrinsic length of about 100 /spl mu/m at quench inception and propagation under the criterion of 3.3 /spl mu/V/cm for ac superconducting wires.