Compact, Low Current Superconductor Coil Operating Above 15 K for Magnetic Cooling

Adiabatic Magnetic Refrigeration (ADR) can achieve much better efficiency, and with fewer moving parts than compressor-refrigerators, making it the choice for space-based instruments that require cooling to the sub-Kelvin range. The low operating currents required for space-based usage, the high operating current densities to keep weight and size down, as well as the benefits of higher operating temperature provided by our “2212” superconductor are unmatched by any other superconducting wire option for powering the ADR’s magnet. The innovation in this program consists of a compact, low current coil wound with a novel, very fine 2212 wire, that operates at about 6 A or lower, that generates in excess of 4 T and that operates at up to 25K (not 10K) with low hysteresis losses in ramped fields, very considerably exceeding the specifications in the guideline put forward by NASA, and exceeding even more so, present state-of-the-art ADR coil capabilities. As a first step, the prototype 2212-based fine wire will be designed and fabricated, with process development to achieve the above described properties. Based on these results, longer length prototype sections will be produced at best design and mode conditions, followed by testing to validate scalability. As a final step, a subscale test coil will be wound and tested with same bore size as the current, low temperature superconductor-based coils, in order to demonstrate the feasibility of fabricating an ADR- type of coil with this wire.