Material and cooling requirements for poly-Bitter resistive magnets and hybrid inserts generating continuous fields up to 50 T

The new National High Magnetic Field Laboratory (NHMFL), equipped with a 40 MW DC power supply, will design and construct the next generation of high field resistive magnets and hybrid inserts generating DC fields up to 50 T. We present a study on the required materials and the necessary cooling characteristics, these magnets need. The configuration selected for this study consists of a combination of thin poly-Bitter and thick Bitter coils optimized in dimensions and power under constraint of maximum design stress and heat removal to obtain maximum field. The study shows that each design requires a different optimum ratio of conductor strength to electrical conductivity and that efficient cooling is only advantageous if strong copper alloys are used. For efficient use of the available power the development of new high strength, high conductivity materials will be necessary. Equally important are improvements in the heat transfer characteristics of these high power density magnets