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Description
High temperature superconductor (HTS) no-insulation (NI) coil is widely applied on high field magnets. In a multiple coil system, the quench behaviour of one coil is considerably affected by other coils through electromagnetic coupling. Meanwhile, quench on one coil can induce a current and fields changing on other coils, which may leads to eddy loss and mechanical degradation on these coils. Both the eddy loss and mechanical degradation are possible induce quenches on these coils finally. However, this has never been elucidated so far. This paper is to understand this underlying process by modelling methods. A multi-physics models are developed for multiple NI coil system by coupling an equivalent circuit network model, a T-A formulation model, a thermal model, and a structural mechanics model. The hot spot quench and over-current quench on one coils is analysed in HTS magnet consisting of 20 NI HTS coils. The current, temperature and strain/stress of all the coils are calculated during the quench. Measures are discussed to improve the thermal stability of the NI HTS magnet. The results and modelling tool developed are very useful for the design and development of high field magnet consisting of NI coils.
