Ultra-high-field superconducting magnets

Abstract

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High Field Properties of NbN Ribbon Conductors

“…For example, a 1 cm wide ribbon with 15 um of NbN and 5 Um of Cu deposited onto both sides, having a J c for the NbN alone of 3.0 x lo A A/cm* at 20 T and 2.0 K (our best ribbon) has an overall J c> including Cu and Hastelloy, in excess of 1 x 10 A^cm at 20 T and 2.0 K. This value is well above the value (3.5 x 10 A/cm ) set by Hoard et al 2 in designing a 20 T magnet operating at 1.8 K. A conductor of this configuration would carry 100 A at 20 T. A cable of 10 to 20 ribbons, possibly with internal cooling, has the potential to satisfy the current requirements of large fusion magnet designs. Also, the higher J in the perpendicular direction should reduce the stability problems associated with the perpendicular field component at the ends of tape-wound solenoids.…”