关键词: 聚变磁体, 托卡马克, 二代超导体, 环向场(TF)线圈, 管内圆芯电缆导体, 交流损耗, T-A法, 电磁热耦合

Abstract: [Objectives] In order to ensure the stable operation of tokamak magnets by preventing reduced stability or quenches caused by excessive heat generation and insufficient cooling, corresponding measures must be adopted to improve the heat dissipation efficiency. Taking the Toroidal Field (TF) coil wound with CORC (Conductor on Round Core)-based Cable-In-Conduit Conductor (CICC) as the research object, this study investigates the AC losses and magneto-thermal coupling characteristics of TF coils in fusion magnets during dynamic excitation and demagnetization processes. [Methods] A magneto-thermal coupling model was constructed using COMSOL finite element simulation software. The T-A formulation method was employed to calculate AC losses during excitation. The effects of excitation speed, steady-state magnetic field intensity after excitation, and the flow rate of 20 K cryogenic helium gas on thermal stability were systematically explored. [Results] The AC loss power during excitation exhibits a positive correlation with excitation speed. The total excitation losses show a positive correlation with steady-state magnetic field intensity. Increasing the flow rate of cryogenic helium gas raises the maximum allowable excitation speed, though cooling efficiency demonstrates a diminishing marginal effect. [Conclusions] The findings provide critical references for optimizing stable operation and cooling configurations of fusion TF coils manufactured using second-generation high-temperature superconducting (2G HTS) tapes.

Key words: Nuclear fusion magnet, Tokamak, 2G HTS, toroidal field (TF) coil, round core cable-in-conduit conductor, AC loss, T-A formulation, electro-thermal coupling