Pub Date : 2025-11-06DOI: 10.1109/TASC.2025.3628587
L. Reccia;D. Laghi;J. Lorenzo;T. Schild;M. Nakamoto;T. Sanchez;S. Brun
IO (ITER Organization) planned cold tests for Toroidal Field (TF) and Poloidal Field (PF1) coils, and a test facility is under development for this specific purpose. The TF coil test campaign foresees a series of tests at half operational current and a final one at full current, 68kA. The latter requires a further development of the facility, due to the severity of the test together with a series of design constraints. Firstly, a stand-alone TF coil is subjected to a stress condition different from the operational one, since it is not part of the entire magnetic system, where centripetal actions are shared and reacted by wedging. This condition results in significant bending of the inboard leg and a strain state potentially affecting the superconductor performance. Secondly, the required supporting structures to mitigate this bending, apart from being effective in increasing the stiffness and structurally sound, must withstand strict requirements in terms of dimension, interface with other components, handling and weight. In this investigation the preliminary design of the necessary auxiliary structure is discussed. The results of the FEM mechanical and thermal analyses show how the design meets the requirements in terms of stresses in the TF coil and strain in the Winding Pack (WP), as well as the structural compliance of both coil and supporting structure, also in compliance with the requirements of assembly and handling in the facility.
{"title":"Preliminary Design of a Supporting Structure for the Full Current Test of ITER TF Magnet","authors":"L. Reccia;D. Laghi;J. Lorenzo;T. Schild;M. Nakamoto;T. Sanchez;S. Brun","doi":"10.1109/TASC.2025.3628587","DOIUrl":"https://doi.org/10.1109/TASC.2025.3628587","url":null,"abstract":"IO (ITER Organization) planned cold tests for Toroidal Field (TF) and Poloidal Field (PF1) coils, and a test facility is under development for this specific purpose. The TF coil test campaign foresees a series of tests at half operational current and a final one at full current, 68kA. The latter requires a further development of the facility, due to the severity of the test together with a series of design constraints. Firstly, a stand-alone TF coil is subjected to a stress condition different from the operational one, since it is not part of the entire magnetic system, where centripetal actions are shared and reacted by wedging. This condition results in significant bending of the inboard leg and a strain state potentially affecting the superconductor performance. Secondly, the required supporting structures to mitigate this bending, apart from being effective in increasing the stiffness and structurally sound, must withstand strict requirements in terms of dimension, interface with other components, handling and weight. In this investigation the preliminary design of the necessary auxiliary structure is discussed. The results of the FEM mechanical and thermal analyses show how the design meets the requirements in terms of stresses in the TF coil and strain in the Winding Pack (WP), as well as the structural compliance of both coil and supporting structure, also in compliance with the requirements of assembly and handling in the facility.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 3","pages":"1-5"},"PeriodicalIF":1.8,"publicationDate":"2025-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145510176","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}
Pub Date : 2025-11-05DOI: 10.1109/TASC.2025.3629544
J. Gawith;J. Trueman
Flux pumps supply current to superconducting magnets without direct electrical contact, eliminating resistive leads and reducing their associated cryogenic load. Automatic flux pumps achieve this by periodically driving a section of the superconductor into the normal state by exceeding its critical current during part of the waveform cycle. Previously reported high-temperature superconductor (HTS) automatic flux pumps rely on bulky drive electronics and nonlinear current waveforms on the primary side for operation. In this work, we present an automatic HTS flux pump that simplifies these requirements by using a pulsed voltage waveform to drive the transformer primary. The system successfully charges an HTS magnet to 120 A dc within 20 s. It utilizes a noninductive bifilar HTS bridge as the self-rectifying element and a resistive copper braid as the transformer secondary. These results demonstrate how automatic flux pumps can be powered by simple dc sources, such as batteries, thereby improving the portability and practicality of HTS magnet power systems.
{"title":"An Automatic HTS Flux Pump With Pulsed Voltage Drive","authors":"J. Gawith;J. Trueman","doi":"10.1109/TASC.2025.3629544","DOIUrl":"https://doi.org/10.1109/TASC.2025.3629544","url":null,"abstract":"Flux pumps supply current to superconducting magnets without direct electrical contact, eliminating resistive leads and reducing their associated cryogenic load. Automatic flux pumps achieve this by periodically driving a section of the superconductor into the normal state by exceeding its critical current during part of the waveform cycle. Previously reported high-temperature superconductor (HTS) automatic flux pumps rely on bulky drive electronics and nonlinear current waveforms on the primary side for operation. In this work, we present an automatic HTS flux pump that simplifies these requirements by using a pulsed voltage waveform to drive the transformer primary. The system successfully charges an HTS magnet to 120 A dc within 20 s. It utilizes a noninductive bifilar HTS bridge as the self-rectifying element and a resistive copper braid as the transformer secondary. These results demonstrate how automatic flux pumps can be powered by simple dc sources, such as batteries, thereby improving the portability and practicality of HTS magnet power systems.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 9","pages":"1-8"},"PeriodicalIF":1.8,"publicationDate":"2025-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145560669","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}
Pub Date : 2025-11-05DOI: 10.1109/TASC.2025.3629027
Tejumadejesu Oluwadamilare;Eby G. Friedman
High current requirements in single flux quantum (SFQ) circuits pose scalability challenges, contributing to issues such as high thermal loads, static power dissipation, and increased sensitivity to flux trapping under nonideal shielding or cool down conditions. AC biasing, successfully used in other superconductive logic families, has been integrated into rapid single flux quantum (RSFQ) circuits and typically includes ac-to-dc converters, introducing area and complexity overhead. This work proposes an alternative method for applying ac biasing to existing RSFQ circuits using inductively coupled bias junctions, eliminating the need for ac-to-dc converters. This approach also combines resistive dc biasing with inductive ac biasing, reducing static power dissipation. The proposed approach targets clock splitters, which are significant contributors to on-chip current demand, achieving an average 94% reduction in splitter current and a 62% reduction in overall system current with a Josephson junction overhead of 6.5% . The technique is compatible with conventional RSFQ system architectures and logic families while significantly enhancing energy efficiency and scalability.
{"title":"AC Biased SFQ Clock Splitters for Current Mitigation","authors":"Tejumadejesu Oluwadamilare;Eby G. Friedman","doi":"10.1109/TASC.2025.3629027","DOIUrl":"https://doi.org/10.1109/TASC.2025.3629027","url":null,"abstract":"High current requirements in single flux quantum (SFQ) circuits pose scalability challenges, contributing to issues such as high thermal loads, static power dissipation, and increased sensitivity to flux trapping under nonideal shielding or cool down conditions. AC biasing, successfully used in other superconductive logic families, has been integrated into rapid single flux quantum (RSFQ) circuits and typically includes ac-to-dc converters, introducing area and complexity overhead. This work proposes an alternative method for applying ac biasing to existing RSFQ circuits using inductively coupled bias junctions, eliminating the need for ac-to-dc converters. This approach also combines resistive dc biasing with inductive ac biasing, reducing static power dissipation. The proposed approach targets clock splitters, which are significant contributors to on-chip current demand, achieving an average 94% reduction in splitter current and a 62% reduction in overall system current with a Josephson junction overhead of 6.5% . The technique is compatible with conventional RSFQ system architectures and logic families while significantly enhancing energy efficiency and scalability.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 9","pages":"1-11"},"PeriodicalIF":1.8,"publicationDate":"2025-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145560667","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}
Pub Date : 2025-11-03DOI: 10.1109/TASC.2025.3628540
Teng Wang;Chao Pan;Yezheng Xiao;Longgui Zheng;Qicai Ni;Yanlan Hu;Yu Wu
The design and development of quench detection for the China Fusion Engineering Test Reactor (CFETR) toroidal field (TF) prototype coil is in progress, which is expected to be completed in the fourth quarter of 2025. According to the quench simulation analysis, voltage detection with a threshold of 200 mV and a delay of 2 s satisfies the quench detection design criteria, that is, the hot spot temperature is less than 150 K. The foundation of a successful quench detection system, of course, is the reliable measurement of the original high-voltage signals, high-precision suppression of inductive voltage noises, and accurate execution of quench discrimination. Key technologies include many different things such as optimal design of installation schemes for co-wound tape (CWT) and co-wound wire, automatic wrapping of CWT, welding and extraction of high-voltage taps, transfer of high-voltage wires and cables, high-resolution data acquisition, and sensitive quench discrimination mechanism. The installation process for the primary compensation circuit and the key processes for high-voltage measurement have been developed successfully to manufacture the subcoils of the CFETR TF prototype coil, and the test results meet the design requirements. These technologies can not only further improve the reliability of CFETR TF prototype coil quench detection but also provide robust assurance for the secure and stable operation of international thermonuclear experimental reactor (ITER) and future full superconducting fusion reactors.
{"title":"Research on Key Technologies of Quench Detection for CFETR TF Prototype Coil","authors":"Teng Wang;Chao Pan;Yezheng Xiao;Longgui Zheng;Qicai Ni;Yanlan Hu;Yu Wu","doi":"10.1109/TASC.2025.3628540","DOIUrl":"https://doi.org/10.1109/TASC.2025.3628540","url":null,"abstract":"The design and development of quench detection for the China Fusion Engineering Test Reactor (CFETR) toroidal field (TF) prototype coil is in progress, which is expected to be completed in the fourth quarter of 2025. According to the quench simulation analysis, voltage detection with a threshold of 200 mV and a delay of 2 s satisfies the quench detection design criteria, that is, the hot spot temperature is less than 150 K. The foundation of a successful quench detection system, of course, is the reliable measurement of the original high-voltage signals, high-precision suppression of inductive voltage noises, and accurate execution of quench discrimination. Key technologies include many different things such as optimal design of installation schemes for co-wound tape (CWT) and co-wound wire, automatic wrapping of CWT, welding and extraction of high-voltage taps, transfer of high-voltage wires and cables, high-resolution data acquisition, and sensitive quench discrimination mechanism. The installation process for the primary compensation circuit and the key processes for high-voltage measurement have been developed successfully to manufacture the subcoils of the CFETR TF prototype coil, and the test results meet the design requirements. These technologies can not only further improve the reliability of CFETR TF prototype coil quench detection but also provide robust assurance for the secure and stable operation of international thermonuclear experimental reactor (ITER) and future full superconducting fusion reactors.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 9","pages":"1-5"},"PeriodicalIF":1.8,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145510211","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}
Pub Date : 2025-11-03DOI: 10.1109/TASC.2025.3628286
C. Martins Jardim;L. García-Tabarés;J. M. Pérez;F. Toral;J. C. Pérez
For the development at CERN (European Center for Nuclear Research) of the post-LHC accelerator infrastructures, HL-LHC (High Luminosity Large Hadron Collider) and FCC (Future Circular Collider), a new generation of energy-efficient magnets with extreme mechanical constraints, capable of generating high-quality magnetic fields up to 14 T (operational) will be required. These magnets will be based on technological knowledge currently under development and new superconducting materials. To foster the Spanish efforts to contribute to these strategic goals, CIEMAT (Research Center for Energy, Environment and Technology), CDTI (Center for Technological Development and Innovation), and CERN signed three collaboration agreements in 2019 within the framework of PRISMAC (Very High Field Superconducting Magnets Program). This paper depicts the progress of the PRISMAC program activities and the tasks foreseen to achieve its goals. PRISMAC is based on three work packages: i) the delivery of the nested orbit correctors MCBXF for the HL-LHC, ii) the construction of a dedicated laboratory at CIEMAT for prototyping and testing high-field magnets, and iii) the development and assembly of Nb3Sn demonstrator magnets for the FCC study. There is an extension of the program for the design and development of High-Temperature Superconducting (HTS) magnets for future needs. The PRISMAC program is outlined, focusing on the commissioning of the new laboratory.
{"title":"PRISMAC: A R&D Program and a New Dedicated Laboratory for Very High Field Superconducting Magnets","authors":"C. Martins Jardim;L. García-Tabarés;J. M. Pérez;F. Toral;J. C. Pérez","doi":"10.1109/TASC.2025.3628286","DOIUrl":"https://doi.org/10.1109/TASC.2025.3628286","url":null,"abstract":"For the development at CERN (European Center for Nuclear Research) of the post-LHC accelerator infrastructures, HL-LHC (High Luminosity Large Hadron Collider) and FCC (Future Circular Collider), a new generation of energy-efficient magnets with extreme mechanical constraints, capable of generating high-quality magnetic fields up to 14 T (operational) will be required. These magnets will be based on technological knowledge currently under development and new superconducting materials. To foster the Spanish efforts to contribute to these strategic goals, CIEMAT (Research Center for Energy, Environment and Technology), CDTI (Center for Technological Development and Innovation), and CERN signed three collaboration agreements in 2019 within the framework of PRISMAC (Very High Field Superconducting Magnets Program). This paper depicts the progress of the PRISMAC program activities and the tasks foreseen to achieve its goals. PRISMAC is based on three work packages: i) the delivery of the nested orbit correctors MCBXF for the HL-LHC, ii) the construction of a dedicated laboratory at CIEMAT for prototyping and testing high-field magnets, and iii) the development and assembly of Nb<sub>3</sub>Sn demonstrator magnets for the FCC study. There is an extension of the program for the design and development of High-Temperature Superconducting (HTS) magnets for future needs. The PRISMAC program is outlined, focusing on the commissioning of the new laboratory.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 3","pages":"1-5"},"PeriodicalIF":1.8,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11224471","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145510175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-03DOI: 10.1109/TASC.2025.3628392
Yuhui Zhang;Yukai Qiao;Yueming Sun;Nicholas M. Strickland;Zhenan Jiang
Assembled conductor on round core (CORC) cables are a promising candidate for future fusion magnets to meet high DC demands. In high-temperature superconductors (HTS) fusion applications, HTS tapes in poloidal field coils are exposed to high magnetic fields (∼ 20 T), high currents (> 25 kA), and low temperatures (20 K). Under these conditions, the superconductors can generate AC losses that may potentially lead to the magnet quenching. Here, considering the HTS layer of the coated conductor, AC losses include magnetization loss from external AC magnetic fields and dynamic loss from the interaction between AC fields and a DC current. The sum of magnetization loss and dynamic loss equals the total loss. In this work, 3D finite element method simulations are used to investigate the averaged AC loss of HTS tapes (Faraday/Theva), used either in a spiral tape or in multilayer CORC cables. The simulations are carried out under AC magnetic fields, with/without DC current, where the magnetic field amplitude reaches up to 8 T at 20 and 50 K. An eight-layer CORC cable exposed to magnetic fields up to 20 T at 20 K is also investigated as a specific case study. The simulation results show that magnetization loss decreases with increasing number of layers at low and medium magnetic fields, due to the shielding effect. However, at high magnetic fields, the magnetization loss of multilayer cables becomes similar due to the shielding effect becoming insufficient to prevent flux penetration at high fields, as the shielding currents reach their critical limits. In addition, the eight-layer CORC cable shows consistency with the other cables at 8 T and follows the same trend up to 20 T at 20 K. Then, a temperature scaling law for the CORC cables is explored, showing that magnetization loss (without current) and total loss of multilayer CORC cables at different temperatures can be scaled using the self-field critical current.
{"title":"Numerical Study of AC Losses in CORC Cables Carrying DC Current Under AC Magnetic Fields Up to 8 T at 20 K and 50 K","authors":"Yuhui Zhang;Yukai Qiao;Yueming Sun;Nicholas M. Strickland;Zhenan Jiang","doi":"10.1109/TASC.2025.3628392","DOIUrl":"https://doi.org/10.1109/TASC.2025.3628392","url":null,"abstract":"Assembled conductor on round core (CORC) cables are a promising candidate for future fusion magnets to meet high DC demands. In high-temperature superconductors (HTS) fusion applications, HTS tapes in poloidal field coils are exposed to high magnetic fields (∼ 20 T), high currents (> 25 kA), and low temperatures (20 K). Under these conditions, the superconductors can generate AC losses that may potentially lead to the magnet quenching. Here, considering the HTS layer of the coated conductor, AC losses include magnetization loss from external AC magnetic fields and dynamic loss from the interaction between AC fields and a DC current. The sum of magnetization loss and dynamic loss equals the total loss. In this work, 3D finite element method simulations are used to investigate the averaged AC loss of HTS tapes (Faraday/Theva), used either in a spiral tape or in multilayer CORC cables. The simulations are carried out under AC magnetic fields, with/without DC current, where the magnetic field amplitude reaches up to 8 T at 20 and 50 K. An eight-layer CORC cable exposed to magnetic fields up to 20 T at 20 K is also investigated as a specific case study. The simulation results show that magnetization loss decreases with increasing number of layers at low and medium magnetic fields, due to the shielding effect. However, at high magnetic fields, the magnetization loss of multilayer cables becomes similar due to the shielding effect becoming insufficient to prevent flux penetration at high fields, as the shielding currents reach their critical limits. In addition, the eight-layer CORC cable shows consistency with the other cables at 8 T and follows the same trend up to 20 T at 20 K. Then, a temperature scaling law for the CORC cables is explored, showing that magnetization loss (without current) and total loss of multilayer CORC cables at different temperatures can be scaled using the self-field critical current.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 9","pages":"1-12"},"PeriodicalIF":1.8,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145510214","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}
Pub Date : 2025-11-03DOI: 10.1109/TASC.2025.3628280
Minhui Li;Junhao Chen;Haolan Chen;Xi Zhu;Mingyang Wang
With the widespread application of high-temperature superconducting (HTS) REBCO tapes in energy, healthcare, and transportation, their operating environments have become increasingly complex, placing higher demands on stability. Although multifilamentary REBCO tapes can reduce AC loss, exposure of REBCO compounds without stabilizing layers leads to moisture-induced degradation and performance failure. This study proposes a plasma-driven film deposition method using an atmospheric pressure plasma jet (APPJ) with hexamethyldisiloxane (HMDSO) to enhance the hydrophobicity of REBCO tapes. Results show that after the plasma film deposition, the water contact angle (WCA) on the tape surface increases from 94° to 138°. A new Si-O-based film with a spherical cluster morphology was deposited onto the tape surface. Scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) confirms that the coating is primarily composed of Si and O rather than the underlying tape elements (Cu, Y, Ba). Furthermore, critical current retention tests revealed a degradation in the critical current of untreated multifilamentary REBCO tapes over time, while the samples treated with plasma-deposited films exhibited minimal variation, indicating excellent critical current stability. After liquid nitrogen bathing, the film maintains considerable stability in hydrophobicity performance and chemical composition, demonstrating the feasibility of the plasma film fabrication for hydrophobicity improvement of superconducting tapes. This study presents an effective plasma coating method to prevent hydrolysis in multifilamentary REBCO tapes, thereby enhancing their electrical stability performance and providing crucial technical support for the design of high-performance tapes.
随着高温超导（HTS） REBCO胶带在能源、医疗保健和交通运输领域的广泛应用，其工作环境变得越来越复杂，对稳定性提出了更高的要求。虽然多纤维REBCO胶带可以减少交流损耗，但暴露在没有稳定层的REBCO化合物会导致水分引起的降解和性能失效。本研究提出了一种大气压等离子体射流（APPJ）与六甲基二硅氧烷（HMDSO）的等离子体驱动薄膜沉积方法，以提高REBCO带的疏水性。结果表明：等离子体膜沉积后，带表面的水接触角（WCA）由94°增加到138°；在带表面沉积了一种具有球形簇状形貌的新型硅基薄膜。扫描电子显微镜（SEM）和能量色散x射线光谱（EDS）证实，涂层主要由Si和O组成，而不是底层的带元素（Cu， Y, Ba）。此外，临界电流保持测试显示，未经处理的多纤维REBCO胶带的临界电流随着时间的推移而下降，而用等离子沉积薄膜处理的样品则表现出最小的变化，表明临界电流稳定性非常好。经过液氮浸泡后，膜在疏水性和化学成分上保持了相当大的稳定性，证明了等离子体膜制备提高超导带疏水性的可行性。本研究提出了一种有效的等离子体涂层方法来防止多丝REBCO胶带的水解，从而提高其电气稳定性，为高性能胶带的设计提供关键的技术支持。
{"title":"Improved Interface Reliability and Critical Current Retention in Multifilamentary REBCO Tapes via a Plasma-Deposited Film","authors":"Minhui Li;Junhao Chen;Haolan Chen;Xi Zhu;Mingyang Wang","doi":"10.1109/TASC.2025.3628280","DOIUrl":"https://doi.org/10.1109/TASC.2025.3628280","url":null,"abstract":"With the widespread application of high-temperature superconducting (HTS) REBCO tapes in energy, healthcare, and transportation, their operating environments have become increasingly complex, placing higher demands on stability. Although multifilamentary REBCO tapes can reduce AC loss, exposure of REBCO compounds without stabilizing layers leads to moisture-induced degradation and performance failure. This study proposes a plasma-driven film deposition method using an atmospheric pressure plasma jet (APPJ) with hexamethyldisiloxane (HMDSO) to enhance the hydrophobicity of REBCO tapes. Results show that after the plasma film deposition, the water contact angle (WCA) on the tape surface increases from 94° to 138°. A new Si-O-based film with a spherical cluster morphology was deposited onto the tape surface. Scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) confirms that the coating is primarily composed of Si and O rather than the underlying tape elements (Cu, Y, Ba). Furthermore, critical current retention tests revealed a degradation in the critical current of untreated multifilamentary REBCO tapes over time, while the samples treated with plasma-deposited films exhibited minimal variation, indicating excellent critical current stability. After liquid nitrogen bathing, the film maintains considerable stability in hydrophobicity performance and chemical composition, demonstrating the feasibility of the plasma film fabrication for hydrophobicity improvement of superconducting tapes. This study presents an effective plasma coating method to prevent hydrolysis in multifilamentary REBCO tapes, thereby enhancing their electrical stability performance and providing crucial technical support for the design of high-performance tapes.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 3","pages":"1-5"},"PeriodicalIF":1.8,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145510169","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}
Pub Date : 2025-11-03DOI: 10.1109/TASC.2025.3626202
S. Tardieu;C. Verdy;N. Ferreira;F. Teyssier;T. Schiavo;F. Lecouturier-Dupouy
New copper–tungsten (W–Cu) composite wires are developed for the winding of non-destructive pulsed magnets. A micrometric Cu powder coated with a nanometric layer of W (1.8 vol%) was used as the starting material. W is chosen for its very high shear modulus, and its introduction at the nanometric scale aims to avoid co-deformation incompatibilities during wire drawing. Composite cylinders were fabricated by cold spraying and then deformed by wire drawing at room temperature, allowing the fabrication of wires.
{"title":"Development of Copper-Tungsten Composite Wires Using Cold Spray and Wire-Drawing for High Magnetic Field Applications","authors":"S. Tardieu;C. Verdy;N. Ferreira;F. Teyssier;T. Schiavo;F. Lecouturier-Dupouy","doi":"10.1109/TASC.2025.3626202","DOIUrl":"https://doi.org/10.1109/TASC.2025.3626202","url":null,"abstract":"New copper–tungsten (W–Cu) composite wires are developed for the winding of non-destructive pulsed magnets. A micrometric Cu powder coated with a nanometric layer of W (1.8 vol%) was used as the starting material. W is chosen for its very high shear modulus, and its introduction at the nanometric scale aims to avoid co-deformation incompatibilities during wire drawing. Composite cylinders were fabricated by cold spraying and then deformed by wire drawing at room temperature, allowing the fabrication of wires.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 3","pages":"1-4"},"PeriodicalIF":1.8,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145510172","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}
The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) is being upgraded from 1.0 GeV to 1.3 GeV (or 1.4 to 2.8 MW). Several water-cooled magnets have been upgraded to transport 30% higher beam energy. Fermilab contributed the magnet design for the new chicane magnets and injection/extraction septum. Designing the magnets was a challenging task because the new magnets required good combined integrated field quality and needed to occupy the old magnets space but with about 20% greater integrated magnetic field. Additional strong requirements applied to the magnets fringe field so as not to disturb the circulating beam. After fabrication of the magnets, an extensive measurement campaign was developed and performed at Fermilab’s Magnet Test Facility. The measurements needed to assess magnet performance and provide comparison to design calculations. These included verification of field strength and harmonics along an 8 m length and 200 mm good field diameter for the chicane dipoles, end-field Hall probe mapping of these magnets, and measurements along two differently curved trajectories within the ∼3 m septum gradient magnet. Details of the measurements and systems are presented along with results and comparison to field models.
{"title":"Oakridge PPU Magnets: Results and Measurements","authors":"J. DiMarco;D. Harding;V. Kashikhin;O. Kiemschies;M. Kifarkis;A. Makulski;J. Nogiec;S. Stoynev;T. Strauss;M. Tartaglia;P. Thompson","doi":"10.1109/TASC.2025.3628299","DOIUrl":"https://doi.org/10.1109/TASC.2025.3628299","url":null,"abstract":"The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) is being upgraded from 1.0 GeV to 1.3 GeV (or 1.4 to 2.8 MW). Several water-cooled magnets have been upgraded to transport 30% higher beam energy. Fermilab contributed the magnet design for the new chicane magnets and injection/extraction septum. Designing the magnets was a challenging task because the new magnets required good combined integrated field quality and needed to occupy the old magnets space but with about 20% greater integrated magnetic field. Additional strong requirements applied to the magnets fringe field so as not to disturb the circulating beam. After fabrication of the magnets, an extensive measurement campaign was developed and performed at Fermilab’s Magnet Test Facility. The measurements needed to assess magnet performance and provide comparison to design calculations. These included verification of field strength and harmonics along an 8 m length and 200 mm good field diameter for the chicane dipoles, end-field Hall probe mapping of these magnets, and measurements along two differently curved trajectories within the ∼3 m septum gradient magnet. Details of the measurements and systems are presented along with results and comparison to field models.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 3","pages":"1-6"},"PeriodicalIF":1.8,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145510173","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}
When researching and designing high-temperature superconducting (HTS) excitation motors, it is crucial to account for the impact of ferromagnetic structures on the critical current and losses in superconducting windings. The finite element methods based on the T-A formulation, H formulation, and other formulations are viable options. However, since the finite element method has to calculate the huge air domain, its computational efficiency is lower than the J-model, which only calculates the superconducting winding domain. Ferromagnetic structures in HTS excitation motors are circular, and the J-model has not been applied in such application. Therefore, to increase the efficiency of the research and design for superconducting windings in HTS motors, this article combines the J-model with the mirror image method and realizes the calculation of critical current density and losses in the superconducting winding of HTS motors. The accuracy of the improved J-model is increased by using current density instead of concentrated current. To further enhance the efficiency of the improved J-model, an adjustment method for calculation step-size is designed to ensure fast convergence and rapid calculations. A two-pole HTS excitation motor model is set up to verify the reliability of the improved J-model. The results demonstrate that the improved J-model achieves high accuracy in calculating critical current density and losses. Meanwhile, the improved J-model also has very high computational efficiency and strong convergence. Therefore, the improved J-model significantly increases the efficiency of research, design and optimization of HTS windings in HTS excitation motors. Moreover, it offers a valuable reference for calculating critical current density and losses based on the J-model in superconducting windings of other superconducting applications involving ferromagnetic structures.
{"title":"Improved J-Model for Calculating Critical Current Density and Losses in Superconducting Windings of HTS Motors","authors":"Jiabo Shou;Chao Luo;Jien Ma;Lei Wang;Cong Wang;Yuang Zheng;Youtong Fang","doi":"10.1109/TASC.2025.3627548","DOIUrl":"https://doi.org/10.1109/TASC.2025.3627548","url":null,"abstract":"When researching and designing high-temperature superconducting (HTS) excitation motors, it is crucial to account for the impact of ferromagnetic structures on the critical current and losses in superconducting windings. The finite element methods based on the <italic>T-A</i> formulation, <italic>H</i> formulation, and other formulations are viable options. However, since the finite element method has to calculate the huge air domain, its computational efficiency is lower than the J-model, which only calculates the superconducting winding domain. Ferromagnetic structures in HTS excitation motors are circular, and the J-model has not been applied in such application. Therefore, to increase the efficiency of the research and design for superconducting windings in HTS motors, this article combines the J-model with the mirror image method and realizes the calculation of critical current density and losses in the superconducting winding of HTS motors. The accuracy of the improved J-model is increased by using current density instead of concentrated current. To further enhance the efficiency of the improved J-model, an adjustment method for calculation step-size is designed to ensure fast convergence and rapid calculations. A two-pole HTS excitation motor model is set up to verify the reliability of the improved J-model. The results demonstrate that the improved J-model achieves high accuracy in calculating critical current density and losses. Meanwhile, the improved J-model also has very high computational efficiency and strong convergence. Therefore, the improved J-model significantly increases the efficiency of research, design and optimization of HTS windings in HTS excitation motors. Moreover, it offers a valuable reference for calculating critical current density and losses based on the J-model in superconducting windings of other superconducting applications involving ferromagnetic structures.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 9","pages":"1-10"},"PeriodicalIF":1.8,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145510212","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}
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