AC loss analysis on high-temperature superconductors with finite thickness and arbitrary magnetic field dependent voltage-current relation

A numerical model is developed for the current distribution in high-temperature superconductors (HTS conductors)subjected to self and applied field. This analysis is based on the two-dimensional Poisson equation for the vector potential. The vector potential is rewritten into an equation of motion for the current density J. The finite thickness of the conductor and the n-power law electric field-current density relations (E-J relations)of the conductor are included in the model. The magnetic field dependence of critical current density J(c) is also included in this E-J relation. The self-field loss obtained with this analysis has good agreement with experimental data. Also the effects of aspect ratio and n value on ac loss are pointed out to be important on the ac loss. (C) 1998 American Institute of Physics. [S0021-8979(98)07022-4].