Numerical analysis of transport AC loss in HTS slab with thermoelectric interaction

Highlight
• Thermoelectric interaction is considered numerically in the analysis of AC loss.
• The temperature has a non-negligible effect on AC loss at high current amplitude.
• Numerical model is applicable to other samples with intrinsic nonlinear relations.

This paper presents an investigation of the AC loss in high temperature superconducting slabs, when applying an alternating transport current of sinusoidal form. The proposed model describing this AC loss is built upon the following coupled physics: the Maxwell’s equations governing the electromagnetic fields, the intrinsic nonlinear relations, and the thermal diffusion equation governing the temperature fields. The numerical results demonstrated that the temperature of the whole slab (interior or exterior) increases monotonously with the frequency and amplitude of the applied alternating current. After considering the local temperature changing effect, it is found that most of the magnetic induction, the critical current density, and the local current density in the slab periodically vary with time with non-sinusoidal form, while the period is either the same or half of that of the applied current, which fully exhibits a typical characteristic of nonlinear systems. Further, the AC loss varying with the amplitude and frequency of the applied current has the power law as almost same as the analytical results based on Bean’s critical state model at low amplitude I0. However, for the case of high current amplitude I0, the numerical results gradually deviate from the analytical results and the local temperature changing has a significant effect on the transport loss.