Superconductivity最新文献

{"title":"Screening-current-induced magnetic fields and strains in a compact REBCO coil in self field and background field","authors":"Yufan Yan ,&nbsp;Donghui Jiang ,&nbsp;Peng Song ,&nbsp;Jeonghwan Park ,&nbsp;Seungyong Hahn ,&nbsp;Yunfei Tan ,&nbsp;Timing Qu","doi":"10.1016/j.supcon.2023.100082","DOIUrl":"10.1016/j.supcon.2023.100082","url":null,"abstract":"<div><p>REBa₂Cu₃O₇₋<em>_x</em> (REBCO) coated conductors, owing to its high tensile strength and current-carrying ability in a background field, are widely regarded a promising candidate in high-field applications. Despite the great potentials, recent studies have highlighted the challenges posed by screening currents, which are featured by a highly nonuniform current distribution in the superconducting layer. In this paper, we report a comprehensive study on the behaviors of screening currents in a compact REBCO coil, specifically the screening-current-induced magnetic fields and strains. Experiments were carried out in the self-generated magnetic field and a background field, respectively. In the self-field condition, the full hysteresis of the magnetic field was obtained by applying current sweeps with repeatedly reversed polarity, as the nominal center field reached 9.17 T with a maximum peak current of 350 A. In a background field of 23.15 T, the insert coil generated a center field of 4.17 T with an applied current of 170 A. Ultimately, a total center field of 32.58 T was achieved before quench. Both the sequential model and the coupled model considering the perpendicular field modification due to conductor deformation are applied. The comparative study shows that, for this coil, the electromagnetic–mechanical coupling plays a trivial role in self-field conditions up to 9 T. In contrast, with a high axial field dominated by the background field, the coupling effect has a stronger influence on the predicted current and strain distributions. Further discussions regarding the role of background field on the strains in the insert suggest potential design strategies to maximize the total center field.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"9 ","pages":"Article 100082"},"PeriodicalIF":0.0,"publicationDate":"2023-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772830723000479/pdfft?md5=aa18d1d395434a3c0a7d6967e6ce67f7&pid=1-s2.0-S2772830723000479-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139014596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Superfluid density dominated junction resistance of bulk polycrystalline YBa2Cu3O7−δ and DyBa2Cu3O7−δ superconductors at low temperature","authors":"Doyel Rakshit,&nbsp;Sourav Das,&nbsp;Ajay Kumar Ghosh","doi":"10.1016/j.supcon.2023.100070","DOIUrl":"10.1016/j.supcon.2023.100070","url":null,"abstract":"<div><p>Resistances of grain junctions of bulk polycrystalline YBa₂Cu₃O_{7−<em>δ</em>} (YBCO) and DyBa₂Cu₃O_{7−<em>δ</em>} (DyBCO) superconductors have been extracted following (i) Ambegaokar- Baratoff (AB) and (ii) de Gennes (dG) equations. Current–voltage (<em>IV</em>) below the critical temperature (<span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span>) has been used to extract transport critical current density (<span><math><mrow><msub><mrow><mi>J</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span>). The variations of the junction resistances, (<span><math><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>N</mi></mrow></msub></mrow></math></span>) with temperature (<em>T</em>) exhibit that below a critical value of the normalised superfluid density (NSD), junctions become very low resistive and exhibit metallicity. Dependence of this feature of <span><math><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>N</mi></mrow></msub></mrow></math></span> on the energy gaps has also been explored. Weak scattering limit is found to be compatible with the maximum of <span><math><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>N</mi></mrow></msub></mrow></math></span> (<em>T</em>) as is observed from the corresponding NSD.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"8 ","pages":"Article 100070"},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772830723000352/pdfft?md5=5963ffa6ba26b554a9398b52332dbed2&pid=1-s2.0-S2772830723000352-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135763592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ic measurement of twisted multifilamentary MgB2 wires with non-magnetic sheath over a wide range of temperatures and fields","authors":"Yukai Qiao ,&nbsp;Matt Rindfleisch ,&nbsp;Mike Tomsic ,&nbsp;Michael D. Sumption ,&nbsp;Naoyuki Amemiya ,&nbsp;Rodney A. Badcock ,&nbsp;Nicholas M. Strickland ,&nbsp;Zhenan Jiang","doi":"10.1016/j.supcon.2023.100072","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100072","url":null,"abstract":"<div><p>All-superconducting rotating machines have the potential for meeting the high power density and high efficiency required for electrical aircraft applications. However, very high AC loss encountered in superconducting armature windings could hinder their development. Multifilamentary MgB₂ wires are one of the promising candidates for the stator windings, due to their potentially low AC loss properties with small filament size and twist pitches. As the first step, the dependence of critical current and <em>n</em>-value on magnetic fields and temperatures <em>I</em>_c(<em>B</em>, <em>T</em>) and <em>n</em>(<em>B</em>,<em>T</em>), which are basic input parameters for AC loss simulation, needs to be measured. In this work, we present transport <em>I</em>_c measurements in three non-magnetic multifilamentary MgB₂ wires (MgB₂/Nb/CuNi/CuZn): one large wire with a 0.70 mm diameter and 25 mm twist pitch, and two small wires with a 0.48 mm diameter each and a 10 mm and 30 mm twist pitch respectively. A four-probe direct current method is used to measure <em>I</em>_c of the MgB₂ wires with variations in temperature (15 – 35 K) and magnetic field (0 – 5.5 T). Full <em>I</em>_c data for the small wire with 10 mm twist pitch was obtained, and the <em>n</em>-values were mostly less than 20. While the <em>I</em>_c data for the large wire at low fields was more limited due to heating, the <em>n</em>-values were higher and could be up to around 100. The difference is attributed to the different filament sizes. Experiments also found that there is no significant hysteresis in the transport critical current measured by decreasing or increasing magnetic fields due to the non-magnetic sheaths. This non-hysteretic characteristic is critical for lowering AC loss because the additional losses from magnetic sheaths can be eliminated. From the magnetic-field dependence of critical current density, an empirical expression has been developed that provides suitable extrapolations to lower fields for the large wire.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"8 ","pages":"Article 100072"},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772830723000376/pdfft?md5=cc68c6b516c6da00e4d7150b36de11dd&pid=1-s2.0-S2772830723000376-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138466284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Review of Moiré superconductivity and application of the Roeser-Huber formula","authors":"Michael R. Koblischka,&nbsp;Anjela Koblischka-Veneva","doi":"10.1016/j.supcon.2023.100073","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100073","url":null,"abstract":"<div><p>Moiré superconductivity represents a new class of superconducting materials since the discovery of superconductivity in magic-angle (1.1°) twisted bi-layer graphene (MATBG), forming a Moiré lattice with a much bigger crystal parameter as the original lattice constant of graphene. Hence, experimentally changing the Moiré twist angle, 0.93° <span><math><mrow><mo>⩽</mo><mi>Θ</mi><mo>⩽</mo></mrow></math></span>1.27, leads to a variation of the superconducting properties and enables a new way of engineering 2D superconducting materials. Details of the robust superconducting state of MATBG as function of charge carrier density, temperature and applied magnetic fields are reviewed. The influence of the top/bottom hexagonal boron nitride layer thickness on the superconducting properties of MATBG was also demonstrated in the literature. In all fabricated MATBG devices, changing of the charge carrier density leads to the appearance of insulating, metallic and even ferromagnetic states, which separate several superconducting domes in the phase diagram (longitudinal resistance, <span><math><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>xx</mi></mrow></msub></mrow></math></span>, as function of temperature <em>T</em> and charge carrier density, <em>n</em>). Further works have considered MATBG combined with WSe₂-layers, twisted bi-layer WSe₂, magic-angle tri-layer graphene (MATTG), and most recently, four-layer (MAT4G) and five-layer (MAT5G) stacks. The differences between the layered, cuprate high-<span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span> superconductors and the Moiré superconductors are compiled together. The collected information is then used to apply the Roeser-Huber formalism to Moiré-type superconductivity to calculate the superconducting transition temperature, <span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span>, using only information of the Moiré lattice and the electronic configuration. To account for the different charge carrier densities in the experimental data sets and the low charge carrier mass demands that a new parameter <span><math><mrow><mi>η</mi></mrow></math></span> must be introduced to the Roeser-Huber formalism to enable the description of several superconducting domes found in the phase diagram for a given Moiré angle. Doing so, the calculated data fit well to the correlation curve defined within the Roeser-Huber formalism.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"9 ","pages":"Article 100073"},"PeriodicalIF":0.0,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772830723000388/pdfft?md5=942bcaf6ce1556389b23f365592e4178&pid=1-s2.0-S2772830723000388-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138489645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metallographic investigation of first full-size high-Jc Nb3Sn cable-in-conduit conductor after cyclic loading tests","authors":"Chao Dai ,&nbsp;Yunhao Liu ,&nbsp;Zichuan Guo ,&nbsp;Yu Wu ,&nbsp;Arend Nijhuis ,&nbsp;Tianjun Xue ,&nbsp;Zuojiafeng Wu ,&nbsp;Jinggang Qin","doi":"10.1016/j.supcon.2023.100071","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100071","url":null,"abstract":"<div><p>In order to verify the feasibility of applying high-J_c Nb₃Sn strand in fusion magnet, a full-size cable-in-conduit conductor (CICC) with short twist pitch (STP) cable pattern was manufactured and tested in SULTAN facility at SPC, Switzerland. Three levels of cyclic electromagnetic (EM) load were applied on the sample stepwise, no visible decrease of current sharing temperature (<span><math><mrow><msub><mi>T</mi><mrow><mi>cs</mi></mrow></msub><mrow><mo>)</mo></mrow></mrow></math></span> was observed until the EM load increased to 80 kA × 10.8 T, after that the <span><math><mrow><msub><mi>T</mi><mrow><mi>cs</mi></mrow></msub></mrow></math></span> decreased dramatically with the EM cycles, which suggested that irreversible deformation, causing a change in the strain state, or even damage has occurred in the superconducting strands. For investigating the reason which caused the conductor performance degradation, the tested conductor was dissected for metallographic observation. Eight segments which subjected to different EM loads were extracted from one of the legs, the geometric feature changes of the cable cross-sections were analyzed and compared. A good correlation was found between the decrease of the <span><math><mrow><msub><mi>T</mi><mrow><mi>cs</mi></mrow></msub></mrow></math></span> and deformation of the cable cross section. A mass of cracks were found on the sub-elements of strands in the segment which subjected to highest EM load, but the amount of crack is much lower in other segments. Combining the analyses, it is speculated that the critical EM load which causes irreversible degradation is between 850 kN/m and 870 kN/m for this conductor. The results could be a reference in high-J_c Nb₃Sn CICC design.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"9 ","pages":"Article 100071"},"PeriodicalIF":0.0,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772830723000364/pdfft?md5=dea17fa524a8df5c4f6a6c81c982a7dc&pid=1-s2.0-S2772830723000364-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138549919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation of axial tensile and fatigue behaviors of HTS round strands","authors":"X.Q. Lai,&nbsp;J.X. Zuo,&nbsp;X.B. Hu,&nbsp;T. Zhang,&nbsp;J.D. Liu,&nbsp;P.Y. Li","doi":"10.1016/j.supcon.2023.100069","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100069","url":null,"abstract":"<div><p>For the development of high-temperature superconducting (HTS) magnet systems of future fusion devices, a novel HTS round strand based on a stacking structure was designed and manufactured using second generation (2G) HTS tapes. Different mechanical loads during operation can result in irreversible degradation of the strand. The axial tension and fatigue loads need particular attention. Therefore, it is important to investigate the electromechanical behavior of the round strand under various axial tension and cyclic loads. In this paper, the axial tensile and fatigue tests were conducted at 77 K, self-field. Taking 95% critical current (<em>I_c</em>) retention as the criterion, the results of the tensile tests revealed that the average tensile stress and strain were as high as 344 MPa and 0.47%, respectively. Fatigue characteristics were also investigated as a function of axial tensile stress. No significant performance degradation was observed up to 100,000 loading cycles with stress amplitudes ranging from 20 MPa to 200 MPa. <em>I_c</em> degradation occurs after 16,000 loading cycles with 380 MPa as the maximum stress. Furthermore, the microscopic defects of the round strand samples due to fabrication imperfections and mechanical loading were investigated using metallographic microscope and scanning electron microscope. These results presented in this paper are useful for comprehending and improving the mechanical behaviors of the strand in high-field and large-scale fusion magnet systems.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"8 ","pages":"Article 100069"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772830723000340/pdfft?md5=22089535b079e26402cfbfd92244a805&pid=1-s2.0-S2772830723000340-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134656497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interface properties and failures of REBCO coated conductor tapes: Research progress and challenges","authors":"Peifeng Gao ,&nbsp;Yameng Zhang ,&nbsp;Xingzhe Wang ,&nbsp;Youhe Zhou","doi":"10.1016/j.supcon.2023.100068","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100068","url":null,"abstract":"<div><p>RE-Ba-Cu-O (REBCO, where RE = Y, Gd, Sm, and other rare earth elements) coated conductor (CC) tapes are promising for applications in high-energy physics and high-field science owing to their significant advantages such as high critical magnetic field, high current density, and the ability to achieve superconductivity at liquid nitrogen temperatures. Nevertheless, the mechanical and superconducting performances of these CC tapes are significantly affected by interface failures, such as interfacial delamination and coating fractures, which arise from the complex interplay of mechanical stress induced by magnet processing, thermal mismatch stress during cooling, electromagnetic stress under high magnetic fields, and thermal stress during quenching. This study comprehensively reviews the interface properties and failure behavior of REBCO CC tapes. First, the research progress in characterizing the intricate interface properties of REBCO CC is systematically reviewed. Furthermore, the interface failure behavior in extreme multifield environments was analyzed and summarized. Subsequently, this study outlines optimization strategies to mitigate interface failure risks in REBCO superconducting magnet structures. Finally, we address the current challenges and future perspectives on interface issues in REBCO CC tapes. By addressing these challenges, this study offers valuable insights for advancing the development and practical implementation of superconducting technologies in diverse applications.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"8 ","pages":"Article 100068"},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772830723000339/pdfft?md5=839e6899444c4bcb4dcb1a4a8cf0d6f7&pid=1-s2.0-S2772830723000339-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134656498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time-dependent development of dynamic resistance voltage of superconducting tape considering heat accumulation","authors":"Chao Li ,&nbsp;Yuying Xing ,&nbsp;Ying Xin ,&nbsp;Bin Li ,&nbsp;Francesco Grilli","doi":"10.1016/j.supcon.2023.100066","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100066","url":null,"abstract":"<div><p>In flux pumps, motors and superconducting magnets, the high temperature superconductor (HTS) coated conductor frequently carries a DC transport current when an oscillating magnetic field is present in the background. Under this circumstance, the interesting effect of dynamic resistance takes place, which can affect the operating performance of superconducting devices: heat accumulation can contribute to the rising temperature of the HTS tape and the dynamic resistance voltage can change accordingly. This article explores the time-dependent development of the dynamic resistance voltage using a numerical modeling considering the thermal effects. After a validation against experimental results, this work investigates the effects of several factors on the structure of the HTS tape on the time-dependent development of the dynamic resistance, thus providing insights toward a better understanding of the time-dependent behavior of HTS tapes under external magnetic fields.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"8 ","pages":"Article 100066"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49699008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fatigue behaviors and damage mechanisms for Nb3Sn triple-helical structure at liquid nitrogen temperature","authors":"Lang Jiang,&nbsp;Zhiwei Zhang,&nbsp;Zhen Yu,&nbsp;Jun Zhou,&nbsp;Huadong Yong,&nbsp;Xingyi Zhang","doi":"10.1016/j.supcon.2023.100065","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100065","url":null,"abstract":"<div><p>Nb₃Sn triple-helical structure is the elementary structure in the superconducting cable of ITER magnets and undergoes prolonged fatigue loading in extreme environments leading to serious damage degradation. In this paper, the fatigue behaviors of the Nb₃Sn triple-helical structure have been investigated by the strain cycling fatigue experiments at liquid nitrogen temperature. The results indicate that Nb₃Sn triple-helical structures with short twist-pitches possess excellent fatigue damage resistance than that of long twist-pitches, such as longer fatigue life, slower damage degradation, and smaller energy dissipation. Meanwhile, a theoretical model of damage evolution has been established to reveal the effects of twist-pitches on fatigue properties for triple-helical structures, which is also validated by the present experimental data. Furthermore, one can see that the Nb₃Sn superconducting wires in a triple-helical structure with the shorter twist-pitches have a larger elongation of helical structure and less cyclic deformation, which can be considered as the main mechanism of better fatigue damage properties for the triple-helical structures during the strain cycling processes. These findings provide a better understanding of the fatigue properties and damage mechanisms for Nb₃Sn triple-helical structures in superconducting cables of ITER magnets.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"8 ","pages":"Article 100065"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49699001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A superconducting wireless energiser based on electromechanical energy conversion","authors":"Hongye Zhang ,&nbsp;Tianhui Yang ,&nbsp;Francesco Grilli ,&nbsp;Wenxin Li ,&nbsp;Paul M. Tuohy ,&nbsp;Ying Xin","doi":"10.1016/j.supcon.2023.100057","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100057","url":null,"abstract":"<div><p>A superconducting magnet (SM) can produce high magnetic fields up to a dozen times stronger than those generated by an electromagnet made of normal conductors or a permanent magnet (PM), and thus has attracted increasing research efforts in many domains including medical devices, large scientific equipment, transport, energy storage, power systems, and electric machines. Wireless energisers, e.g., high temperature superconducting (HTS) flux pumps, can eliminate the thermal load from current leads and arc erosion of slip rings, and are thus considered a promising energisation tool for SMs. However, the time-averaged DC output voltage in existing HTS flux pumps is generated by dynamic resistance: the dynamic loss is unavoidable, and the total AC loss will become significant at high frequencies. This study introduces a highly efficient superconducting wireless energizer (SWE) designed specifically for SMs. The SWE takes advantage of the inherent properties of a superconducting loop, including flux conservation and zero DC resistivity. Extensive theoretical analysis, numerical modelling exploiting the <strong>H</strong>-<em>ϕ</em> formulation, and experimental measurements were conducted to demonstrate the efficiency and efficacy of the novel SWE design. The electromechanical performance and loss characteristics of the SWE system have also been investigated. Compared to conventional HTS flux pumps, the proposed SWE has lower excitation loss, in the order of 10⁻¹ mW, and thus can achieve a high system efficiency of no less than 95%. Furthermore, it has a simpler structure with higher reliability, considered ready for further industrial development. In addition to deepening the understating of the intricate electromechanical dynamics between magnetic dipoles and superconducting circuits, this article provides a novel wireless energisation technique for SMs and opens the way to step changes in future electric transport and energy sectors.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"7 ","pages":"Article 100057"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49698719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}