Speaker
Description
High-temperature superconducting (HTS) magnets, with their superior current-carrying capacity and high operating temperatures, have shown considerable potential for applications in medical imaging, particle accelerators, power transmission, and scientific instrumentation. However, HTS coated conductors (CCS) are susceptible to significant shielding current effects due to their high aspect ratio, which considerably affects the magnetic field distribution and becomes a major limitation in the performance of HTS magnets. The shielding current effect causes central magnetic field attenuation, magnetic field drift, and degradation of field uniformity, presenting substantial challenges to the field stability required for high-precision applications, such as particle accelerators. The characteristics of shielding currents are closely related to the E-J relationship of the superconductor, with the n-value serving as a critical parameter that influences the distribution and behavior of shielding currents.
This study focuses on high-temperature superconducting dipole magnets and employs the T-A homogenization model to develop a numerical simulation framework in COMSOL Multiphysics. The distribution characteristics of shielding currents and their induced field (SCIF) effects on the magnetic field were systematically analyzed. The variations in shielding current-induced fields and magnetic field drift under different n-value conditions were analyzed, and the effectiveness of current reversal scanning techniques in reducing magnetic field drift was further explored. The results reveal that the distribution of shielding currents and their induced fields significantly affect magnetic field performance. As the n-value increases, the shielding current-induced field diminishes, while the influence of the n-value on magnetic field drift follows an opposite trend. Moreover, current reversal scanning effectively reduces magnetic field drift, thereby enhancing the operational stability of the magnet.
This study provides a comprehensive analysis of the shielding current effects in high-temperature superconducting dipole magnets and their influence on magnetic field performance. The findings offer valuable theoretical insights and engineering guidance for optimizing the design of superconducting magnets in high-precision applications such as particle accelerators.
