High Accuracy Computation for Design of Hight Temperature Superconducting Magnet using Multiscale Electromagentic Analysis

近年来，REBCO超导线圈在高场磁体（如加速器、核磁共振、核磁共振）中的应用研究与开发备受关注。在REBCO线圈中，磁场的径向分量在绕组带中感应出较大的屏蔽电流。因此，屏蔽电流产生的不规则磁场影响了高精度的空间和时间磁场分布。本文提出了一种基于有限元法、边界积分方程和快速多极子法的数值模拟方法。同时，对屏蔽电流在REBCO线圈中产生的不规则磁场进行了数值模拟和实验研究。阐明了屏蔽电流对磁场分布的影响。该工作有助于设计具有减小屏蔽电流产生的磁场、提高磁场均匀性和时间稳定性的高温超导磁体。

In recent years, the research and development on the applications of REBCO superconducting coil to the high field magnets (e.g. accelerator, NMR, and MRI) attract considerable attention. In REBCO coil, large screening currents are induced in the winding tape by the radial component of the magnetic field. As a result, the irregular field generated by the screening currents affects the high-accuracy magnetic field distribution spatially and temporally. In this study, we developed a novel numerical simulation based on the finite element method, boundary integral equation, and fast multipole method. And, we numerically and experimentally evaluated the irregular field generated by screening currents in REBCO coil. We clarify the effect of the screening currents on the magnetic field distribution.This work contributes to the design of high temperature superconducting magnet with reduction of field generated by screening current, the homogeneity and temporal stability of field.