STABILITY-CRITERION FOR COMPOSITE SUPERCONDUCTOR OR LARGE ASPECT RATIO

The stability of a tape/film superconductor of a large aspect ratio is studied by considering the transverse normal zone behaviour subjected to an instantaneous thermal disturbance. Different types of behaviour in terms of stable superconducting operation, current sharing, quench ing and superconductivity recovery have been identified. A stability c riterion was developed based on heat conduction analyses for the curre nt sharing steady state and the quenching steady state. The criterion was validated by the transient stability behaviour results for an NbTi superconductor obtained through the finite difference method. The eff ects of operating current density and the composite superconductor's d imensions on the stability performance were also investigated.