Investigation of magnetic hysteresis in HTS coil by means of numerical modelling using T-A formulation

Frequent task in the numerical modelling of a superconducting magnet generating AC or pulsing fields is the evaluation of AC loss. Commonly, after solving the electromagnetic problem, the loss is calculated by integrating in time and volume the density of dissipated power, obtained locally as the product of electrical field and current density. However, the loss can be also determined from the product of current and voltage detected on the device terminations, in the way analogous to electrical measurement. Fortunately, this voltage signal can be easily determined in the frequently used T-A formulation. It can be further used for more detailed comparison with experiment, in particular the creation of magnetic hysteresis loops relating the flux linkage to the coil current. Methodology is illustrated on Benchmark #3 problem published by the HTS Modelling Workgroup.