Stability-optimized, force-cooled, multifilamentary superconductors

A numerical program has been written to calculate the temperature-time history of a uniformly pulse-heated composite superconductor cooled by supercritical helium in forced convection. The program determines the maximum sudden temperature rise from which the conductor can still recover the superconducting state. The program includes the effects of (1) current sharing, (2) the temperature variation of the specific heat of both the matrix and the superconductor, and (3) the temperature variation of the heat transfer coefficient. Using this program, one may optimize force-cooled conductors with respect to stability by simultaneously varying the copper-to-superconductor (Cu/SC) ratio and the metal-to-helium ratio. Use of stability-optimized conductors allows a given stability level to be maintained for a particular field and bath temperature and the pressure drop and pumping losses to be reduced.