High temperature superconducting magnet operating above 15 K for ADR cooling

This Phase II program will develop a much highernbsp;operating temperature superconductingnbsp;coilnbsp;and deliver anbsp;full-scale prototype that establishes the capabilitynbsp;of exceeding the requirements set forth in topic area S.109 for Sub-Kelvin Cooling ADR (Adiabatic Demagnetization Refrigeration).nbsp;Specifically, the coil willnbsp;generatenbsp;a ramped magnetic field of 4Tnbsp;at or above temperatures ofnbsp;15 K.nbsp;It will utilize a new first-its-kindnbsp;small diameter wire based on the Bi2212 high temperature superconductor (HTS),nbsp;that is now developednbsp;and proven bynbsp;the Phase I programnbsp;to meetnbsp;diameter,nbsp;transport current andnbsp;loss propertiesnbsp;required for ADR coils, and with itsnbsp;fabrication being amenable tonbsp;scale up. Thisnbsp;wire ofnbsp;lt;nbsp;0.16 mm diameternbsp;exhibits 3 times higher current density than standard 1 mm diameter wires.nbsp;Its designnbsp;includes axial twisting and unmerged filaments for reducing ramped field loss, thin insulation, and current densitynbsp;to meet specifications for up to 20K operation at 4T field, as requirednbsp;for next level ADR coil advances.nbsp; In this Phase II program, fabrication techniques for up tonbsp;5 kmnbsp;piece lengthsnbsp;will be established, with the Bi2212 ceramic superconductor in its unreacted form during coil winding followed by in situnbsp;reactionnbsp;into its high Jc form. A full length, full radial build prototype demo coilnbsp;will be designed, developed,nbsp;built, tested and delivered to NASA for evaluation and validation, attaining a TRL of 8nbsp;upon completion. This wire type is also applicable to Actuators and Other Cryogenic Devices that are described in the NASAnbsp;topic area, as well as in other importantnbsp;ramped and ac field coil types,nbsp;for example in all-superconducting much lighter-weightnbsp;wind generatorsnbsp;and higher powder density motors.