Development of light weight, high current density, superconducting magnets

High field, high current density superconducting magnets can be achieved with force-cooled, cable-in-conduit conductors while maintaining good stability and structural integrity. The weight of the conductor was reduced by using aluminum instead of stainless steel for the conduit. A 1-km long Al-conduit conductor was produced by continuous extrusion of Al-tube on the cable and then drawing to the final size and rectangular shape. The structural weight was further reduced by using carbon-fiber reinforced composite, instead of stainless steel. Small test coils with copper conduit were built first to test the above ideas and to measure the stability margins of a cable-in-conduit conductor with void fractions less than 30%, substantially lower than have been used elsewhere. >