Design of All-Superconducting User Magnets Generating More Than 40 T for the SuperEMFL Project

The aim of the SuperEMFL project is to design a 32 T and a 40 T or more all superconducting magnets, and to improve the development of very high magnetic fields. To generate such high magnetic inductions, a high temperature superconducting (HTS) magnet is inserted into a low temperature superconducting (LTS) magnet. The latter can be either a 150 mm user bore diameter magnet generating 19 T or a 250 mm user bore diameter generating 15 T, and will operate in liquid helium at 4.2 K. To reach high magnetic fields of 32 T and 40 T respectively, the HTS insert is made of metal-as-insulation (MI) windings of REBCO tape and can be designed as a single solenoid or as nested coils. This article focuses on the design of the HTS insert for the 40 T+ magnet, based on a multi-physics parametric study under constraints of geometry, current margin on the load line taking into account different anisotropic fits of the critical current of REBCO conductor, mechanical stress and deformation with analytical formulations of MI windings. Different designs are studied including high volume and high field magnets.