Analysis on Current and Magnetic Field Distribution of Gourd-Shaped HTS Plates With Multiple Narrow Notches

Magnet stacked by gourd-shaped high temperature superconducting (HTS) plates has the function of magnetic flux density amplification and flux accumulation, and can operate in closed-loop persistent current mode (PCM), which has the potential as a high field magnet. However, the gourd shape and stacked structure result in uneven current distribution in the radial direction and among each plate, which affects the magnetic field uniformity and excitation efficiency. This paper proposes an architecture of gourd-shaped HTS plate with multiple narrow notches to improve the electromagnetic performance. Specifically, multiple narrow notches are cut on the HTS plate to form multiple smaller gourd-shaped closed loops, and the REBCO films of each loop are mutually insulated and connected via the Hastelloy layer. Finite element models of a single plate and multi-plate stacking are established, and the influence of notches on current and magnetic field distribution is analyzed. Results show that cutting notches on the HTS plate can optimize the current distribution in the radial direction and among each plate, and enhance the uniformity of the magnetic field, thereby improving the excitation performance of the magnet. This study provides a feasible optimization scheme for the design of closed-loop HTS stacked magnets, which can improve their performance in practical engineering applications.