Coupled transient thermal and electromagnetic finite element analysis of quench in MICE coupling magnet

Abstract

The superconducting coupling magnet used for the international Muon Ionization Cooling Experiment (MICE) will be passively protected through coil subdivision and quench back simultaneously. The design of such type quench protection system requires detailedly understanding of the heat transfer and electromagnetic process in the magnet during quench process. A coupled transient thermal and electromagnetic finite element model was developed to study the quench process of the coupling magnet. This model sequentially solves two different physics environments, one is thermal physics environment and the other one is coupled-electromagnetic-circuit physics environment. The two environments are coupled by applying results from one environment as loads in another one. The results such as current, hot spot temperature, resistance and over voltage during quench process are presented. The results of this model were compared with that of a semi-empirical model, and the respective advantages of both models were pointed out. The quench propagation process in the coupling magnet and the effect of the quench back on the speeding up the quench process were analyzed. The goal of such work is to predict the quench evolution of the coupling magnet in detail and guide its protection scheme.