A novel concept for a compact high-field magnet coil is introduced. This is based on stacking slit annular discs cut from bulk rare-earth barium cuprate ((RE)BCO) ceramic in a Bitter-like architecture. Finite-element modelling shows that a small 20 turn stack (with a total coil volume of < 20 cm³) is capable of generating a central bore magnetic field of > 2 T at 77 K and > 20 T at 30 K. Unlike resistive Bitter magnets, the high-temperature superconducting (HTS) Bitter stack exhibits significant non-linear field behaviour during current ramping, caused by current filling proceeding from the inner radius outwards in each HTS layer. Practical proof-of-concept for this architecture was then demonstrated through fabricating an uninsulated four-turn prototype coil stack and operating this at 77 K. A maximum central field of 0.382 T was measured at 1.2 kA, with an accompanying 6.1 W of internal heat dissipation within the coil. Strong magnetic hysteresis behaviour was observed within the prototype coil, with ≈30% of the maximum central field still remaining trapped 45 min after the current had been removed. The coil was thermally stable during a 15 min hold at 1 kA, and survived thermal cycling to room temperature without noticeable deterioration in performance. A final test-to-destruction of the coil showed that the limiting weak point in the stack was growth-sector boundaries present in the original (RE)BCO bulk.

中文翻译：

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由渗银 (RE)BCO 陶瓷块制成的概念验证类苦 HTS 电磁体

介绍了紧凑型高场磁体线圈的新颖概念。这是基于在苦味结构中堆叠从大块稀土钡铜酸盐 ((RE)BCO) 陶瓷切割而成的狭缝环形盘。有限元建模表明，小型 20 匝堆栈（总线圈体积为 < 20 cm ³ ) 能够产生中心孔磁场 > 77 K 时 2 T 和 > 30 K 时为 20 T。与电阻 Bitter 磁体不同，高温超导 (HTS) Bitter 堆栈在电流斜坡期间表现出显着的非线性场行为，这是由每个 HTS 层中从内半径向外进行的电流填充引起的。然后，通过制造非绝缘四匝原型线圈组并在 77 K 下运行，演示了该架构的实际概念验证。在 1.2 kA 下测得的最大中心磁场为 0.382 T，伴随着 6.1 W 的内部热量线圈内的耗散。在原型线圈内观察到强磁滞行为，在电流移除 45 分钟后，最大中心磁场的约 30% 仍保持被捕获状态。该线圈在 1 kA 电流保持 15 分钟期间保持热稳定，并能经受热循环至室温，性能没有明显恶化。对线圈的最终破坏测试表明，堆叠中的限制弱点是原始 (RE)BCO 块体中存在的生长扇区边界。