Abstract
In the present paper, a model for the temperature take-off condition of superconductors cooled in a liquid coolant is presented to estimate the maximum operating current and allowable thermal disturbance in the critical current-margin design criterion for high performance magnet stability. In the model, the take-off time of conductor temperature is estimated as the sum of transient heat conduction and macrolayer evaporation periods. The former is estimated by a transient heat conduction analysis and an activation criterion of pre-existing nuclei. To estimate the latter, the macrolayer model proposed by Haramura and Katto for steady-state critical heat flux is extended to transient states. Prediction from the present model is in good agreement with the experimental data of the take-off time.
