A Nonequilibrium Themodynamic Effect on a Flux Distribution in a Superconductor under a Longitudinal Magnetic Field

The electromagnetic behavior of a superconducting tape with moderate pinning strength was investigated experimentally under the situation where the transport current and the longitudinal magnetic field were swept proportionally so that the angle of the total magnetic field at each tape surface is kept unaltered. While the usual critical state model predicted a translational penetration of fluxoids under this experimental condition, the observed result showed that fluxoids inside the specimen rotate by themselves in spite of no apparent driving torque. This experimental result can be attributed to the nonequilibrium thermodynamic effect that fluxoids choose a process with a smaller energy dissipation.

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