2-D numerical model for estimation of ac losses in high-tc superconducting tapes

A tiro-dimensional numerical diffusion model which estimates self-field ac losses in High-Tc Superconducting (HTS) tapes is developed. The HTS tape is simulated as a nonlinear conductor whose equivalent resistivity is derived from a power law E-J characteristic. Results of various field quantities and ac losses for a range of currents are presented. It has been shown that for current densities less than the critical value the loss mechanism is mainly hysteretic, as defined by the critical state model. However, as the current approaches its critical value, the tape enters a resistive regime, characterised by flux creep / flow, where the critical state model is no more valid.