Ultra high-current superconducting cables for a 2.2-Tesla, 300-kilojoule energy storage magnet

These 2.2-T, 300-kJ magnets are to operate at 10 to 12 kA with a safety factor in critical current of about 50 percent at 10 kA. The conductor exhibits low losses in addition to being stable. A flat conductor was designed using 1224 copper-matrix, monofilament wires combined in two stages of cabling followed by two stages of flat braiding. Two of these conductors were constructed, one with wire already on hand and the second using wire made specifically for this application. Two rectangular conductors were using 315 and 319 mixed-matrix multifilament wires combined in three stages of cabling followed by compaction in a Turk's head. The maximum transport current capabilities of these cables were measured in hairpin shaped samples with the straight section under test in perpendicularly applied fields.