Progress in the Construction of a 20 T REBCO Insert Coil for High-Field All-Superconducting Magnets

Detailed design of REBCO-based magnets ideally relies on knowledge of the full angular and wide temperature range characterization of the critical current Ic of the REBCO coated conductors (CC) at high magnetic ﬁelds. In practice, however, obtaining Ic(B, T, θ) data by the commonly used electrical transport technique is expensive, tedious, and diﬃcult, due to high critical current values that exceed 2000 A for B ‖ ab-plane (θ = 90 deg). The conductors are often damaged during angular transport measurements at angles approaching the ab-plane. Therefore, so far, REBCO magnets have been designed without full Ic(B, T, θ) data sets. Here, we present Jc(B, T, θ, ) results for more than twenty samples of CC all made to the same advanced pinning speciﬁcation produced by SuperPower Inc. For this, we employed torque magnetometry, benchmarking the results to transport Ic measurements mostly made away from ab-plane, ﬁnding good agreement with scaling factors ≈ 1 − 1.3. What is striking is the huge variety of properties exhibited by the samples, even for CC made recently. Given the huge attention now being paid to the eﬀects of screening currents and to the torques generated by oﬀsets between the tape plane and the local magnetic ﬁeld vector, our data set suggests some caution in detailed design of such magnets without having data of the type presented here.

Section: Introductionmentioning

confidence: 90%

Rapid assessment of REBCO CC angular critical current density J _c(B, T = 4.2 K, θ) using torque magnetometry up to at least 30 tesla

Jaroszyński

Constantinescu

Miller

et al. 2022

“…Notable works include the 'little big coil' REBCO insert [2] and the 32 T all-superconducting magnet [3][4][5] developed by the National High Magnetic Field Laboratory (NHMFL), the 800 MHz REBCO insert magnet by MIT [6][7][8][9], the 32.35 T magnet [10] by the Institute of Electrical Engineering, Chinese Academy of Science (IEECAS), and the 26.4 T all-HTS magnet by SuNAM Co., Ltd and MIT [11,12]. Several ultra-highfield magnets are being developed, including the 40 T allsuperconducting user magnet by NHMFL [13], the 835 MHz REBCO magnet by MIT [14,15], the 35 T all-superconducting magnet by the Institute of Plasma Physics, Chinese Academy of Science (ASIPP) and Tsinghua University [16][17][18], and the 35 T all-REBCO magnet by SuNAM [19].…”

Section: Introductionmentioning

confidence: 99%

Experimental study on screening-current induced strain in REBCO insert coils: under critical current control and operation current cycles

Shao,

Zhang,

Xin

et al. 2024

Self Cite

The screening-current effect is an inhomogeneous distribution of current density inside the REBCO conductors. The additional strain induced by the screening current, known as screening-current induced strain (SCS), is considered to affect the structural integrity of REBCO windings, especially when operating high-field REBCO insert magnets. In this work, we wound and tested a series of 50-turn REBCO coils inside a 10 T LTS external to investigate the influencing mechanism of multiple electromagnetic factors on SCS. We varied the critical current in different coils by different heat treatment procedures. Each coil was tested individually, experiencing a external field cycle and multiple operation current cycles at constant external fields. The extreme scenario for each coil was being energized to 400 A while the external field was 10 T. We adapted the discrete-coupled model to estimate the hoop strain distribution, monitored the experimental results by multiple strain gauges at the outermost turn. Test coil with a lower critical current endured a lower maximum hoop strain. When we were energizing the test coils, hoop strain increased at the edge of REBCO tapes while remaining nearly constant in the middle region. Additionally, the maximum hoop strain at the outermost turn decreased after each excitation cycle. This work could be an experimental reference for optimizing the electromagnetic design and the excitation scheme during the development of high-field REBCO magnets.

“…Based on a 70 mm 14 T low temperature superconducting (LTS) background magnet, 19.8 T and 24 T all superconducting hybrid magnets have been successfully obtained [10,11]. The 35 T all superconducting hybrid magnet project is also underway [12]. Motivated by the recent achievements, a project was launched at ASIPP to design, construct, and operate an all-HTS highfield conduction-cooled user magnet based on the NI winding technology.…”

Section: Introductionmentioning

confidence: 99%

26.86-tesla direct-current magnetic field generated with an all-REBCO superconducting magnet

Zhang,

Hu,

Guo

et al. 2024

Self Cite

This paper reports an all REBCO (REBa2Cu3Ox, where RE=Y, Gd) superconducting magnet that generated a direct-current magnetic field of 26.86 T at 4.2 K in self-field, which is the highest magnetic field achieved by the high temperature superconducting (HTS) magnet. The magnet consists of a stack of 10 double pancake (DP) coils wound with two different width REBCO tapes, and the no-insulation (NI) winding technology was applied to increase its engineering current density. The inner and outer winding diameters and overall height of the magnet are 30 mm, 103.98 mm, and 102.6 mm, respectively. In order to control the stress risk in HTS magnet, the over-banding made of high elastic modulus stainless steel tapes was employed to the magnet. In addition, no obvious degradation was found in the performance of the magnet after quench at 26.86 T of 295.5 A. These test results demonstrate the great potential of REBCO magnets in high field applications.