Challenges and Opportunities in Developing High Field Superconducting Magnets

Ziad Melhem

Recent Advancements in high temperature superconductor (HTS) materials are enabling a new class of high field (HF) magnets for a variety of applications. HF magnets >25 T will be developed using LTS and HTS coils. Commercially available HTS wires and tapes have now been developed with very high critical current densities and long lengths enabling high field “insert” coils. Large bore, high field “outsert” solenoid magnets that use low temperature superconductors (LTS) conductors have been developed to provide background fields in a cold bore of between 100 and 320 mm diameter with an associated central field of 20 and 12 Tesla respectively operating at 4.2 Kelvin without the need for complex cryogenics. This new “outsert” technology is enabling major steps forwards in ultra-high field technology. Magnets are under development in laboratories around the world operating at T=4.2K with central flux densities in excess of 25 Tesla. NHMFL at Tallahassee has successfully demonstrated a 32 Tesla superconducting magnet using a 15 Tesla /250 mm developed at Oxford Instruments

We will present challenges which have to be met to provide such background magnets, including quench energy management, coil interactions, coil structure and cryogen handling. The challenge of incorporating HTS coils within the ultra-high field magnet products of the future is described. We look ahead to further opportunities in LTS and HTS integration to enable wider applications for experimentation in the physical sciences and extend the capabilities of high field magnet facilities worldwide.