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ISSN: 2772-8307
Copyright © 2026 Shanghai Jiaotong University. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
cited:12
Superconducting materials − tools to combat with climate change
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Article Number:Article 100113
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cited:17
Suppression of flux avalanches in YBCO superconducting thin films by coating metal investigated using magneto-optical imaging
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Article Number:Article 100101
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Abstract
Corresponding email:zhangxingyi@lzu.edu.cn
Flux avalanches, prevalently existing in superconducting thin films, can cause catastrophic breakdowns of electromagnetic properties and even irreversible damage to superconducting materials. Metal coating is an effective way to suppress the flux avalanches in superconducting thin films. Nevertheless, it is difficult to reveal the suppression mechanisms due to the challenge of effectively separating the simultaneous eddy currents and heat exchange in the metal coating. In this work, the eddy currents and heat exchange in the Ag metal coating are separated by setting a thermal insulation layer, and its inhibiting effect on the flux avalanches of the YBCO superconducting thin films is elucidated. The results indicate that eddy currents play an important part in suppressing magnetic flux avalanches, and their effect strengthens with increasing Ag thickness. Meanwhile, employing the double-exposure method, the flux avalanche velocity of YBCO superconducting thin films was measured, revealing a significant decrease in the magnetic flux avalanche velocity due to suppression by eddy currents. Moreover, a theoretical model was established to investigate the influence of eddy currents on the motion of a single vortex, and the calculated results showed good agreement with the experiments. These findings provide a better understanding of the flux avalanches and their suppression in YBCO superconducting thin films.
Abstract
Corresponding email:kumuds@barc.gov.in
The Proton Improvement Plan (PIP)-II project is part of Fermilab’s upgrade of its proton accelerator complex, to provide a powerful, high-intensity proton beam to the laboratory’s upcoming research program. The project includes an 800 MeV superconducting (SC) linear accelerator (linac), with five flavours of cavities and cryomodules. The medium energy section of the linac contains two types of superconducting Single Spoke Resonator (SSR) RF cavities (SSR1 and SSR2), which are interleaved with strong solenoid focusing lenses. A unified design of the solenoid has been developed, with one solenoid design satisfying both SSR1 and SSR2 requirements. The integral focusing strength requirement of 4.5 T2m with a full width half maximum (FWHM) of 180 mm indicates the peak field strength ∼ 6.8 T in the magnet aperture, necessitating a superconducting design within the limits of NbTi as magnet wire strand. These are complex combined units that include one focusing solenoid with bucking coils to minimize fringe fields and four corrector coils each, with independent current leads to produce dipole and quadrupole fields. To simplify the current lead design and reduce complexity, the project opted conduction cooling for these magnets, thus requiring a redesign compared to previous prototype bath cooled units. Existing designs for high energy accelerators adopt bath cooled design of the solenoid focusing lenses for medium energy cryomodules. The present design explores a unique and technically superior solution for the cryomodule operation by decoupling the magnet and cavity cooling to certain extent. Reliability in cryomodule operations shall be studied after integration of magnets in the Linac beamline. Here we discuss the design requirements, challenges, electromagnetic design, superconducting wire selection and the results from magnetic measurements of the first pre-series units.
cited:18
Numerical simulations on the AC loss of REBCO stacks under rotating magnetic fields
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Article Number:Article 100111
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Abstract
Corresponding email:jfang@bjtu.edu.cn; Zhenan.Jiang@vuw.ac.nz
AC loss presents a significant challenge for high-temperature superconducting (HTS) rotating machines. To date, the behaviour of total AC loss (Qtol) (with current) and magnetization loss (Qm) (without current) in a single HTS tape under rotating magnetic fields (RF) have been explored. However, a research gap remains in understanding how these findings translate to the more complex HTS windings of rotating machines. Further exploration is needed to understand the loss behaviour of more complex HTS structures, such as HTS stacks. In this work, Qtol and Qm, in the HTS stacks under RF and a perpendicular AC standing wave magnetic field are numerically investigated. Two different RF models are considered: one is the Uni-RF model, characterized by a uniform field with equal field amplitudes and phases at each position, and the other is a non-uniform field created by a rotating Halbach array, referred to as the Hal-RF model. The dependence of AC loss on parameters such as the number of tapes in the stacks, tape width (2a), and the inclination angle (α) of tapes, which refers to the angle between the normal direction of the stack and the vertical direction, have been explored. The number of tapes in the stacks ranges from 1 to 16, α ranges from 0° to 90°, and the tape width includes 4 mm and 40 mm. Additionally, different rotating field directions are also considered. Interestingly, the analytical values from Brandt and Indenbom equation for Qm of a superconducting strip (BI-strip) are close to Qm results of the stacks under the standing wave at high fields, while they are over twice as high as those in the Hal-RF model at 1 T. This suggests the BI-strip equation is not reliable for predicting Qm under RF at high fields. We also show in the Hal-RF model that different rotation directions of the field lead to varying Qm and Qtol when asymmetric Jc (B, θ) data are applied. Moreover, it has been observed that the inclination angle has no impact on Qm under uniform RF while significantly impacts both Qm and Qtol in the Hal-RF model.
cited:7
Enhancing in-field performance of GdBCO coated conductors by cooperative irradiation with Ti ions and protons
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Article Number:Article 100112
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Abstract
Corresponding email:guhw@mail.iee.ac.cn; dingfazhu@mail.iee.ac.cn
Irradiation can accurately manipulate defects and adjust pinning landscapes within REBa2Cu3O7-δ (REBCO, RE: rare earths) coated conductors (CCs). This study reports a productive method to dramatically boost the in-field critical current density (Jc) for GdBCO CCs using cooperative irradiation with Ti ions and protons. Remarkably, the in-field Jc of commercial CCs can be almost doubled at a wide range of temperatures and magnetic fields. Defects of various sizes induced by cooperative irradiation are more uniform distribution through the entire GdBCO film to improve the vortex pinning characteristics, thereby enhancing the in-field performance of the GdBCO CC. This method highlights how combining different particle irradiation types can tailor defect size and distribution, optimizing pinning landscapes for commercial REBCO CCs.
cited:62
Advancements in dynamic characteristics analysis of superconducting electrodynamic suspension systems: Modeling, experiment, and optimization
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Article Number:Article 100114
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Abstract
Corresponding email:lihaitao@swjtu.edu.cn
Superconducting electrodynamic suspension (EDS) presents numerous advantages, including large suspension gaps, high lift-to-drag ratios, and lower requirements for track irregularities. Recent advancements in superconducting materials have further enhanced the feasibility of this technology, and hence multiple research institutions are actively developing and improving this high-speed rail technology. Superconducting EDS achieves passive suspension and guidance by the interaction between ground null-flux coils and onboard superconducting magnets, forming an electromechanical coupled system. Thus, electromechanical coupling modeling and equivalent experimental methods are essential in evaluating and optimizing this system. This article reviews the research on dynamic characteristics analysis of superconducting EDS, focusing on modeling and experimental methods. Firstly, it revisits the development history of superconducting EDS and the new opportunities brought by advancements in superconducting materials. Secondly, it discusses various modeling approaches for the suspension system, emphasizing their benefits and limitations. Thirdly, it describes equivalent experimental methods and their respective application scenarios. Then, it reviews important conclusions and possible optimization methods related to dynamic performance and electromechanical coupling research. Additionally, the sliding window method is introduced to improve computational efficiency in vehicle dynamics modeling. This article provides insights into the current state and future directions of superconducting EDS research, serving as a valuable reference for researchers and engineers.
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