Stability of SC composite at rapid current charging and against pulsed heating

Numerical analyses of superconducting (SC) wire stability for rapid charging are discussed. It was discovered that the dependence of maximal current on charging rate was non-monotonic for rapid charging using commercial AC frequencies. The SC wires can be stable at levels noticeably higher than those obtained in quasisteady-state analysis of small perturbations using the frozen-flux model. The initial current distribution strongly influences the stability of the wire against pulsed disturbances changing critical energy; not only quantitatively, but also qualitatively. The possibility of transition to the normal state due to stability loss rather than due to overheating above critical temperature should be taken into account as the most-probable reason for quench. The results obtained point out that transposed conductors with uniform current distribution should be used from the stability standpoint rather than twisted conductors.