A novel and fast electromagnetic and electrothermal software for quench analysis of high field magnets

Abstract

High-field superconducting REBCO magnets contain several coils with many turns. For these magnets, electro-thermal quench is an issue that magnet designers need to take into account. Thus, there is a need for a fast and accurate software to numerically model the overall performance of full-scale magnets. High temperature superconductors can be modeled using different techniques for electro-magnetic and thermal (finite element method) analysis. However, it takes a lot of time to model the electro-magnetic and electro-thermal behavior of superconductors simultaneously, especially for non-insulated or metal-insulated coils. In addition, most of the available methods ignore screening currents, which are an important feature of REBCO magnets. We have developed a novel software programmed in C++, which performs coupled electro-magnetic and electro-thermal analysis using variational methods based on Minimum Electro-Magnetic Entropy Production (MEMEP) and Finite Difference, respectively. The developed software, which takes screening currents into account, is applied to axi-symmetric fullscale magnets of more than 32 T field strength under the SuperEMFL project for thermal quench reliability during standard operation. We show that the magnets incorporating non-insulated coils are more reliable against quench than the metal insulated coils. Also, realistic cooling conditions at boundaries is essential for such simulations. The model developed can be used for a quick and complete electro-magnetic and electro-thermal analysis of superconducting high field magnets.