A FEM Simulation Model to Calculate Local Currents and Voltages of NI REBCO Coil With Both Screening Current and Transverse Current Considered

Numerical simulations of no-insulation REBCO magnet should be able to calculate the transverse current flowing along the turn-to-turn contact path and screening current induced by the nature of superconductivity. Mataira et al. reported an invaluable finite-element model using rotated anisotropic resistivity and validated the model by comparing simulation results between the proposed model and the well-known distributed circuit network model. As a result, they addressed the key challenge of conventional analysis models, which have not calculated screening current and transverse current simultaneously. However, an insufficient part remains, as discussions of local current and voltage distributions have not yet been made. Here we report a FEM simulation model to address the remaining issue while numerically improving computation simplicity and speed. This model fundamentally employs H-formulation, homogenized current density domain, and homogenized contact resistivity domain, referring to the research of Mataira et al., but the definition and the supplemental conditions are incorporated to enable calculating local currents and voltages. In this paper, we will validate the proposed model through numerical study and then demonstrate the model's practicability by comparing simulated and measured results.