In fusion applications, AC loss is generated in poloidal field (PF) coils of HTS fusion magnets, when superconductors are exposed to AC magnetic fields and carry DC currents. AC loss generated in this process includes two parts: magnetization loss from shielding currents generated by the external AC magnetic field and dynamic loss from the dynamic resistance due to the interaction between DC currents and AC magnetic fields. Here the total loss is the sum of the magnetization loss and dynamic loss. AC loss could potentially lead to a quench of the magnet under conditions of high magnetic fields (~20 T), high currents (>25 kA), low temperatures (20 K), and a frequency of around 10 Hz. To meet the demands of high operating currents, conductor on round core (CORC) cables are emerging as a promising candidate for next-generation fusion magnets. To date, there have been limited works focusing on simulation studies of AC loss of CORC cables under AC magnetic field and carrying DC current. Furthermore, these works have been carried out at magnetic fields below 100 mT and at 77 K. Notably, there have been no reports on the dynamic loss and total loss using measured Jc(B, θ) and n(B, θ) under high magnetic fields and at low temperatures, where Jc(B, θ) represents the magnetic field and field angle (θ) dependent critical current density.

In this work, we perform 3D FEM (Finite element method) AC loss simulations of the CORC cables using the T-A formulation, where T and A are the current vector potential and magnetic vector potential, respectively. AC loss characteristics of CORC cables are studied using the measured Jc(B, θ) and n(B, θ) under the magnetic field amplitude up to 8 T at 20 K and 50 K. The simulation results are compared with analytical values. Furthermore, the scaling behaviours of AC loss in the CORC cables are explored.