IEEE Transactions on Applied Superconductivity最新文献

{"title":"An Analytical Methodology to Dimension Self-Supporting Structures in Cos-Theta Superconducting Accelerator Magnets","authors":"Jesús Ángel García-Matos;Fernando Toral;Daniel Gavela","doi":"10.1109/TASC.2025.3564128","DOIUrl":"https://doi.org/10.1109/TASC.2025.3564128","url":null,"abstract":"Analytical approaches for dimensioning self-supporting structures in cos-theta superconducting magnets are notably scarce in the literature, despite their interest. The dimensions of these structures influence both material costs and the spacing between the coils and the iron yoke, a parameter that can significantly impact the efficiency of the superconductor depending on the design. Therefore, an analytical methodology is proposed here to dimension the self-supporting structures of cos-theta magnets, usually collar-based, by limiting the radial deformation caused by their electromagnetic forces. This approach could enable a more efficient conceptual design phase, as well as the assessment of existing simulation models. The main goal of this article is to present the core concepts of this methodology and apply them to some examples to evaluate its potential. First, the dimensioning of a standalone dipole serves as a case guide, and then the methodology is tested on the well-known design of the Tevatron. Finally, it is applied to the particularly difficult case that sparked its development: the MCBXF orbit correctors required for the high luminosity large hadron collider (HL-LHC) upgrade. In these magnets, the nested configuration implies a challenging coupling between magnetic and mechanical designs, and the simulation results provide a valuable basis for comparison with the analytical calculations.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 4","pages":"1-12"},"PeriodicalIF":1.7,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144090695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurement of AC Loss of Double-Layer Shielded YBCO Cable Model With Different Voltage Leads","authors":"Hailu Zhai;Yonghu Ma;Zhuyong Li","doi":"10.1109/TASC.2025.3563891","DOIUrl":"https://doi.org/10.1109/TASC.2025.3563891","url":null,"abstract":"In this article, a model of double-layer shielded YBCO cable is measured and analyzed by six different voltage leads. Under the current distribution of different layers, the loss characteristics measured by VO-lead, S-lead, and CO-lead are studied, respectively, and the relationship between the losses measured by different voltage leads is demonstrated. The experimental results show that the loss measured by S-lead is very small compared with the loss measured by VO-lead in the YBCO cable model, especially in go–return mode. The loss of the outer shield varies with the change of the magnetic field’s magnitude and direction, while the loss of the inner conductor is basically not affected by the magnetic field of the shield. Under the two current transportation modes, the loss of the CO-lead is the addition or subtraction of the S-lead and VO-lead. The loss in go–go mode is obviously bigger than that in go–return mode, which is due to the different direction of magnetic field produced by the conductor and shield. In addition, the comparative analysis with the BSCCO cable model more fully illustrates the ac loss characteristics of the double-layer wire shielded YBCO cable model. The YBCO wire has obvious advantages in reducing the ac loss of high-temperature superconducting cables.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 6","pages":"1-5"},"PeriodicalIF":1.7,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144281303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design, Construction, and Operational Testing of Dry-Wound Conduction-Cooled React-and-Wind MgB$_{2}$ Magnet","authors":"Wonseok Jang;Jaemin Kim;Geonyoung Kim;Chaemin Im;Seyong Choi;Jung Ho Kim;Jun Hyuk Choi;Dong Gun Lee;Seungyong Hahn;Sangjin Lee","doi":"10.1109/TASC.2025.3560228","DOIUrl":"https://doi.org/10.1109/TASC.2025.3560228","url":null,"abstract":"This study details the design, construction, and operational testing of a dry-wound conduction-cooled react-and-wind MgB<inline-formula><tex-math>$_{2}$</tex-math></inline-formula> magnet. A turn-coloring method was employed for the precise dry winding of round wire, ensuring the winding was completed as per design specifications. Mechanically and thermally stable copper ring-shaped current lead structures with solder-filled helical grooved path were developed for the reacted wire. Following the cryogen-free cooling setup, the magnet was charged, resulting in a quench event at a current lower than the designed operating level. Analysis suggests that an unexpected heat source within the coil winding, combined with the absence of a pre-load structure that resulted in insufficient conduction cooling paths, led to localized heat accumulation and a subsequent quench. These findings highlight the need for improvements in magnet design and manufacturing, particularly in incorporating a coil pre-load structure to enhance thermal management and ensure the long-term reliability of conduction-cooled MgB<inline-formula><tex-math>$_{2}$</tex-math></inline-formula> magnets.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-5"},"PeriodicalIF":1.7,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143925149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"AC Loss Calculation of High Temperature Superconducting Coils Based on a Surrogate Model","authors":"Linjie Zhou;Yihan Wang;Qi Yuan;Xiaowei Song;Liang Li;Qiuliang Wang","doi":"10.1109/TASC.2025.3561097","DOIUrl":"https://doi.org/10.1109/TASC.2025.3561097","url":null,"abstract":"AC losses have a significant impact on the design and operation of superconducting power devices. Therefore, fast and accurate estimation of AC losses is essential. However, calculating AC losses in high-temperature superconducting (HTS) coils often requires considerable computational resources. To address this, a time-series surrogate model based on a convolutional neural network (CNN) is proposed. The model is trained using sample points <italic>X</i> (e.g., HTS coil parameters and current profiles) and corresponding AC loss responses <italic>Y</i> obtained from finite element analysis (FEA). It integrates a self-attention hybrid convolution module and a current change perception mechanism to extract deep temporal features, and employs an adaptive threshold to enhance open-set recognition and prediction robustness. The model's accuracy is validated against COMSOL simulation results, demonstrating that it significantly improves computational efficiency while maintaining high prediction accuracy.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-5"},"PeriodicalIF":1.7,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143908386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Simulations in Stand-Alone REBCO Coils Under Rotating Magnetic Fields","authors":"Yuan Wang;James G. Storey;Jin Fang;Timothy J. Haugan;Zhenan Jiang","doi":"10.1109/TASC.2025.3561042","DOIUrl":"https://doi.org/10.1109/TASC.2025.3561042","url":null,"abstract":"Large ac loss in the high-temperature superconducting (HTS) armature windings carrying ac under a rotating magnetic field poses a significant challenge for high power-to-weight ratio all-HTS rotating machines. Understanding the loss behavior of HTS coils in rotating magnetic fields and exploring methods for loss reduction are essential. This study numerically investigates the total ac loss (<italic>Q</i>_tot) (with current) and magnetization loss (<italic>Q</i>_m) (without current) in HTS coils under nonuniform rotating magnetic field. The losses of three 4-turn HTS coils are compared, which are designed with a 4 mm wide tape, a striated tape with two 2 mm filaments, and a striated tape with four 1 mm filaments, respectively. In addition, ac loss in the coils at 77 and 65 K is calculated and evaluated. Simulation results show that, under rotating magnetic fields, the striated structure of the coils significantly reduces both <italic>Q</i>_tot and <italic>Q_m</i>. At high fields (e.g., above 200 mT for <italic>Q_m</i> at 77 K), compared to the loss in the un-striated coil, the loss in the coil designed with the two-filament striated tape decreased by almost half, and the loss in the coil designed with the four-filament striated tape was reduced to nearly a quarter. Interestingly, we also show that under rotating magnetic fields, <italic>Q_m</i> and <italic>Q</i>_tot can be effectively scaled with the critical current of either the coil or the tape. This suggests that losses at different temperatures can potentially be estimated using their respective critical currents.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 4","pages":"1-8"},"PeriodicalIF":1.7,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143896408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Delay Balancing With Clock-Follow-Data: Optimizing Area Delay Tradeoffs for Robust Rapid Single Flux Quantum Circuits","authors":"Robert S. Aviles;Phalgun G K;Peter A. Beerel","doi":"10.1109/TASC.2025.3561036","DOIUrl":"https://doi.org/10.1109/TASC.2025.3561036","url":null,"abstract":"This article proposes an algorithm for synthesis of clock-follow-data designs that provide robustness against timing violations for rapid single-flux quantum (RSFQ) circuits, minimizing area costs subject to a given performance constraint. Since all RSFQ logic gates must be clocked, properly sequencing the data flow is a challenging problem that often requires the insertion of many path balancing D flip-flops (DFFs), leading to a substantial increase in area. To address this challenge, we present an approach to insert DFFs and schedule their clock arrival times, partially balancing the delays within the circuit. Our algorithm achieves a target throughput while minimizing area overhead. Our algorithm can account for expected timing variations and, by adjusting the bias of the clock network and clock frequency, the resulting circuits can adjust for unexpected timing violations postfabrication. Quantifying the benefits of our approach with a benchmark suite with nominal delays, we yield an average 1.48x improvement in area delay product (ADP) over high frequency full path balancing designs and a 2.07x improvement in ADP over the state-of-the-art (SOTA) robust circuits provided by SOTA multiphase clocking solutions.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 4","pages":"1-9"},"PeriodicalIF":1.7,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143908364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Densification Effects on Critical-Current Dependence on Longitudinal Strain in Bi2Sr2CaCu2O8+x Wires","authors":"Najib Cheggour;Emsley L. Marks;Jianyi Jiang;Ernesto Bosque;David C. Larbalestier","doi":"10.1109/TASC.2025.3559406","DOIUrl":"https://doi.org/10.1109/TASC.2025.3559406","url":null,"abstract":"There is undoubted new interest in applying Bi₂Sr₂CaCu₂O₈₊<italic>_x</i> (Bi-2212) superconducting round wires for ultra-high fields above 20 T. We investigated effects of filament densification in a high-quality Bi-2212 wire made with fine Engi-Mat powder by comparing critical-current <italic>I_c</i> dependence on longitudinal strain <italic>ϵ</i> among samples reacted under 5- and 50-bar overpressure during the partial-melt process. The Walters spring apparatus we used for transport <italic>I_c</i>(<italic>ϵ</i>) measurements had a high sensitivity that helps detect the first onset of irreversible damage, as well as determine other characteristic strains that describe the transition of <italic>I_c</i>(<italic>ϵ</i>) from weak to steeper dependences. Results show a noticeable improvement of all the tensile characteristic strains as a result of densification. For example, average value of the irreversible strain limit <italic>ϵ</i>_irr increased from 0.3% for 5-bar samples to 0.4% for 50-bar specimens. Moreover, the response of densified samples to strain was significantly more homogeneous along the sample length, independent of the measurement mode used. These improvements, which happened in conjunction with an increase of <italic>I_c</i> by a factor 2.5 at 16 T and 4.2 K, are plausibly due to the elimination of pores that can concentrate stress in strained, nondensified samples where they act as crack initiators. Sensitivity of densified samples to longitudinal compression, on the other hand, increased for strain values beyond −0.28% . In this case, we believe that the continuum of Bi-2212 material in densified samples facilitates the propagation of strain-induced buckling defects as compared to nondensified samples where pores may slow this propagation and keep damage more localized. The benefits of densification, nevertheless, largely outweigh this increase of sensitivity at high compression as <italic>I_c</i> remained significantly higher than that of nondensified samples. These results reveal very positive effects of filament densification on the conductor's strain properties that add to the significant boost of <italic>I_c</i> it induces.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 6","pages":"1-11"},"PeriodicalIF":1.7,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143929708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heat Treatment of Large Nb3Sn Coil for CRAFT TF","authors":"Yifei Wu;Min Yu;Ming Deng;Weijie Gu;Bin Hu;Baozhu Zhang;ZhongRen Li;Ying Wang;Wei Wen;Yu Wu;Jinggang Qin;Weijun Wang","doi":"10.1109/TASC.2025.3558800","DOIUrl":"https://doi.org/10.1109/TASC.2025.3558800","url":null,"abstract":"The fabrication of a prototype toroidal field (TF) coil for the Comprehensive Research Facility for Fusion Technology (CRAFT) represents a critical component of the China Fusion Engineering Test Reactor project. The CRAFT TF coil, characterized by its distinctive “D” shape, measures approximately 19.5 m in length, 11.5 m in width, and 1.1 m in height. The coil incorporates Nb₃Sn cable-in-conduit conductors in both its high-field and medium-field windings. Owing to the intense sensitivity of Nb₃Sn superconductors to stress and strain, the manufacturing process will adhere to the established “wind and react” methodology. Among the various manufacturing stages, heat treatment emerges as a pivotal step in the production of TF Nb₃Sn coil. We have engineered China's largest superconducting coil heat treatment facility, incorporating a fully argon-purged oven environment. This investigation primarily addresses the computational modeling and experimental validation of thermal gradients and fluid dynamics within the system. The design specifications, structural configuration, and processing parameters of the CRAFT TF heat treatment system have been experimentally validated. System performance evaluation demonstrates compliance with technical specifications, particularly in maintaining temperature uniformity within ±5 °C during the critical 650 °C stabilization phase.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 4","pages":"1-7"},"PeriodicalIF":1.7,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143875082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of Coil Structure and Operating Frequency on Performance of Superconducting Wireless Power Transfer","authors":"Dongxu Wang;Wenhao Li;Jinxing Zheng;Xiaotong Cui;Sisi Peng;Difan Zhou;Yanqun Guo;Chuanbing Cai","doi":"10.1109/TASC.2025.3558332","DOIUrl":"https://doi.org/10.1109/TASC.2025.3558332","url":null,"abstract":"High-temperature superconducting (HTS) coil magnets possess extremely high quality factors, therefore having unique advantages when applied to wireless power transfer (WPT) systems especially under low-frequency conditions. The dependence of peak output power and transfer efficiency of an HTS WPT system on the operating frequency varies with the design of the coils because the structure of the coils significantly affects the resonant frequency and ac loss of the HTS WPT system. In this work, a high-power HTS WPT system, including the transfer characteristics under different coil structures, current-carrying conditions, and operating frequencies, has been investigated based on the finite-element simulation to find the optimized operating frequency band and coil structure. It has been found that the change of the inner radius and turn gap in both the solenoid and pancake coils induces a predictable transition frequency change. As the gap is varied, the transfer efficiency remains relatively constant for both coil types. However, for solenoids, reducing the gap value enhances the transferred power, whereas for pancake coils, increasing the gap value augments the transferred power. A transfer efficiency as high as 98.86% or more can be achieved under the optimal conditions.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 4","pages":"1-9"},"PeriodicalIF":1.7,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143892533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"AC Losses Analysis on a Twisted Stacked-Tape Cable With Stepped Grooves","authors":"Junfeng Yang;Yifeng Li;Tao Ma;Zhonghang Li;Peng Yu","doi":"10.1109/TASC.2025.3558431","DOIUrl":"https://doi.org/10.1109/TASC.2025.3558431","url":null,"abstract":"This article mainly shares an ac loss numerical study of a stacked Yttrium Barium Copper Oxide (YBCO) cable with stepped grooves in 77 K. The model divided YBCO tapes to three layers to balance the accuracy and efficiency. AC loss contributions and Eddy current losses are estimated in detail at various magnetic fields and frequencies. A conventional configuration of TSTC is researched for comparison. With the same number of tapes, the stepped-slot structure is less affected by the magnetic field, resulting in a higher critical current and a lower ac loss compared to the traditional structure. When the current frequency is varied, the stepped-slot structure cable also exhibits lower ac losses. The ac losses in the superconducting layer are greater than the Eddy current losses, which is in contrast to the traditional structure where the Eddy current losses far exceeds the ac losses. As for the study on tape configuration, a more balanced distribution of tapes between the two slots in the stepped-slot structure leads to a reduction in both the external field and frequency dependence, thereby improving the ac losses performance.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 4","pages":"1-6"},"PeriodicalIF":1.7,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}