Coupled electro-magnetic and electro-thermal model for non-insulated and metal-insulated high field magnets

Nov. 30 18:50-19:10

*Enric Pardo1, Anang Dadhich1, Philippe Fazilleau2
Institute of Electrical Engineering, Slovak Academy of Sciences, Slovakia1
CEA, Universite Paris-Saclay, France2

Non-insulated (NI) and metal-insulated (MI) coils in superconducting REBCO high-field magnets provide electro-thermal stability. However, current transfer between turns through the metal causes transient currents and magnetic fields, increasing the AC loss and requiring longer times to charge the magnet. Therefore, magnet design and optimization needs numerical modeling. Although 3D modeling provides the full description, it is highly time consuming. In this contribution, we propose an effective cross-sectional 2D modeling method to model the screening currents and turn-to-turn currents in non-insulated coils within high-field magnets. This technique is based on the Minimum Electro-Magnetic Entropy Production method (MEMEP) [1,2], which is programmed in C++ and enables parallel computing [2,3]. First, we benchmark this method with a different method based on the A-phi formulation [4] coded in Matlab language. By means of MEMEP, we analyze the screening currents, instantaneous AC loss and generated magnetic field in tentative designs of high-field superconducting magnets generating more than 32 T. In addition, we developped a finite difference method, programmed in C++, to model the electro-thermal quench properties of the windings. The model developed can be used for a quick and complete electro-magnetic and electro-thermal analysis of practical superconducting applications, specially for high field magnets.

[1] E Pardo, J Souc, L Frolek, Electromagnetic modelling of superconductors with a smooth current–voltage relation: variational principle and coils from a few turns to large magnets, Supercond. Sci. Technol. 28, 044003 (2015)
[2] E Pardo, M Kapolka, 3D computation of non-linear eddy currents: Variational method and superconducting cubic bulk, J. Comp. Phys. 344, 339-363 (2017)
[3] E Pardo, Modeling of screening currents in coated conductor magnets containing up to 40000 turns, Supercond. Sci. Technol. 29, 085004 (2016)
[4] P Fazilleau and G Dilasser, Vortex shaking study with use of linear voltage-current law, Supercond. Sci. Technol. 35, 045007 (2022).

Keywords: High magnetic field magnets, Non-insulated coils, Screening current modelling, Electro-thermal quench modelling