AC losses, flux jumps and quench behavior of copper-clad NbTi superconducting wire under coil simulation conditions

AC losses, flux jumps and quench behaviour of copper-clad single core wires of Nb-50%Ti are investigated under coil simulation conditions. At a frequency of 27 Hz an ac magnetic field and an inphase ac current up to 0.525 T and 99 A, respectively, are applied. The temperature is varied between 4.2 and 1.9 K. Measurements for several ratios of current field and external field are reported. It results, that ac losses and flux jump values are determined only by the effective surface field and the temperature. The quench behaviour is different. Obviously, it is independent of the occurance of flux jumps and influenced by the heat transfer conditions.