Stability criteria and critical energy in superconducting cable-in-conduit conductors

Abstract The so-called ‘well cooled’ criterion is now used extensively to characterize stability in the design of superconducting cable-in-conduit conductors. Using a simplified analytical model we have been able to derive a very simple formula which directly yields the critical energy of such a conductor, for the case of a constant heat transfer coefficient between the strands and helium. This formula, in agreement with numerical simulations, shows that the ‘well cooled’ criterion is not a guarantee of a high stability margin in terms of energy.