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Artículos de revistas sobre el tema "High temperature superconductors Superconducting magnets Cryostats"
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1
Demina, Anna Andreevna, A. V. Safonov, O. A. Kovalchuk, E. R. Zapretilina, I. Yu Rodin y E. N. Andreev. "DEVELOPMENT AND TESTING PROTOTYPE OF HTS MODULE FOR THE SYSTEM OF MAGNETIC LEVITATION OF VEHICLE". Transportation systems and technology 1, n.º 1 (15 de marzo de 2015): 37–48. http://dx.doi.org/10.17816/transsyst20151137-48.
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In recent years increasingly discusses the prospects of application of high-temperature superconductors (HTS) as the winding current-carrying elements of magnetic systems for various purposes. It seems particularly attractive possibility of such systems at liquid nitrogen temperature. The article describes the prototype of module of the magnetic system which is made on the basis of high-temperature superconducting tapes, designed for the installation and testing on a working model of a static levitation. In the working model levitation of the platform carried by the interaction of the magnetic field of the assembly of permanent magnets mounted on the platform with a field similar to assemblies located in the track structure. Compact HTS module replaces the two assemblies of permanent magnets mounted on the platform. Each block of the module represents HTS racetrack coil with current inputs, power structure, positioning system and bracing which is placed in a cryostat, providing at minimum wall thickness of the required mechanical strength and thermal insulation at liquid nitrogen temperature. The prototype of unified superconducting module successfully passed preliminary tests.
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Filippov, Dmitry Maksimovic. "Peculiarities of simulation of magnetic field in electromechanical nodes of magnetic-levitation transport system by the method of secondary sources". Transportation systems and technology 1, n.º 2 (15 de diciembre de 2015): 49–61. http://dx.doi.org/10.17816/transsyst20151249-61.
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In recent years increasingly discusses the prospects of application of high-temperature superconductors (HTS) as the winding current-carrying elements of magnetic systems for various purposes. It seems particularly attractive possibility of such systems at liquid nitrogen temperature. The article describes the prototype of module of the magnetic system which is made on the basis of high-temperature superconducting tapes, designed for the installation and testing on a working model of a static levitation. In the working model levitation of the platform carried by the interaction of the magnetic field of the assembly of permanent magnets mounted on the platform with a field similar to assemblies located in the track structure. Compact HTS module replaces the two assemblies of permanent magnets mounted on the platform. Each block of the module represents HTS racetrack coil with current inputs, power structure, positioning system and bracing which is placed in a cryostat, providing at minimum wall thickness of the required mechanical strength and thermal insulation at liquid nitrogen temperature. The prototype of unified superconducting module successfully passed preliminary tests.
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GOOD, J. y D. BRACANOVIC. "25 TESLA HTS MAGNET INSERT COIL IN ZERO BOIL OFF CRYOSTAT". International Journal of Modern Physics B 23, n.º 12n13 (20 de mayo de 2009): 2842–45. http://dx.doi.org/10.1142/s0217979209062426.
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The development of High Temperature Superconductors (HTS) conductors makes it possible to build very high field superconducting magnets up to at least 25 T. Previously, the only way to obtain a steady field of 25 T for research would be to use water cooled copper solenoids. To achieve 25 T in a 50 mm working space would require about 10 MW of power with a large water cooling plant to carry away the heat. With such high powers involved it is difficult to have a stable and quiet magnetic field environment in which to make sensitive measurements such as NMR. Both capital and operating costs are high so few such facilities exist worldwide. This makes a superconducting magnet of 25 T a very attractive proposition. Figure 1 shows that the critical current of HTS as compared to NbTi and NbSn . The latter can be used up to a limit of about 20 T at 4.2 K. The HTS on the other hand shows the potential of much higher fields. The two main issues in magnet design are the maximum critical current and the maximum stress that a conductor or coil structure can support. For the inner sections of the coil the forces are modest but as the diameter increases towards the outside of the coil hoop stress becomes the dominant issue. [Formula: see text] Cryogenic has built a magnet system with first generation BSCCO conductor. It is designed to run at 4.2 K. It has a three section design, two of conventional superconductor and one of HTS. • The outer winding is made from NbTi giving a field of 9 T, in a bore of 225 mm. The coil is made from 21 km of NbTi wire graded from 1 to 0.6 mm diameter. • A middle coil of NbSn bronze route conductor providing a field of 14 T in 140 mm diameter. • An inner set of HTS coils. These are in the form of 3 coaxial windings made from silver matrix BSCCO conductor supplied by American Superconductor. This conductor has a critical current of 100 A at 77 K in zero field. At 4 K in low field the current is very much higher. The set of three BSCCO windings has a gauss per amp of 157 and when run on its own at a current of 300 A provides a field of 4.7 T, although currents above 275 A begin to show significant resistive losses in the conductor. The inner BSCCO coils are separately powered from the outer magnet. In a test of the full magnet system the BSCCO coil is ramped up at various background fields up to 13 T. The resulting voltage loss across the BSCCO is shown in Fig. 2. This test shows that the BSCCO conductor can operate up to 275 A quite successfully independent of the background field with just a slight increase in resistive losses presumably from the joints between conductor being magneto-resistive or due to flux flow in the conductor. [Formula: see text] Since the BSCCO coils were made new 2nd generation conductors have become available made from thin films of YBCO on a stainless steel backing. These have a much higher effective current density. A 4 mm wide tape of BSCCO is 0.4 mm thick but carries a similar current to an YBCO tape of 0.01 mm or even 0.05 mm thickness. Table 1 shows the properties of different conductors compared. Interestingly the conductors are not just higher current density but also more flexible and stronger in tension. [Formula: see text] A new coil has now been produced from 0.1 mm Super Power material of a size that can fit inside the existing winding so that the combination can produce above 6 T providing a total field of 20 T at 4.2 K in a working bore of 38 mm. Now that the new 2nd generation YBCO based conductors have become available it is intended to exchange the BSCCO coils for YBCO windings which will allow this magnet to operate at much higher fields of up to 25 T. At this field it will be the highest field superconducting magnet worldwide. The magnet is housed in a liquid helium cryostat. To reduce helium consumption a powerful 2nd stage cryocooler is fitted to the cryostat. The first stage cools a shield around the liquid helium to 45 K. The second stage has a cooling power of 1.5 W at 4.2 K and is used to recondense helium gas evolved from the magnet. In operation, with no current in the leads to the cryocooler it is able to condense more gas than that evolved from the cryostat so the liquid helium level will increase with time. Except at the highest currents the cryostat is a zero loss magnet system. A cross section of cryostat and magnet is show in Fig 3. [Formula: see text] The power required for the cryocooler is 6.5 kW while that for the magnet power supplies and ancillary electronics is 2 kW giving a combined power requirement of 8.5 kW. This compares very favourably with the typical value of 10 MW required by a water cooled copper solenoid to achieve the same field. Note from Publisher: This article contains the abstract only.
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Antonov, Yuri F. "Levitation and Lateral Stabilization Device Based on a Second-Generation High-Temperature Superconductor". Transportation Systems and Technology 5, n.º 4 (24 de diciembre de 2019): 115–23. http://dx.doi.org/10.17816/transsyst201954115-123.
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The superconducting levitation device comprises a stationary magnetic rail of permanent magnets and a cryostat on a vehicle with a second-generation high-temperature tape superconductor placed in the cryostat, folded in a stack or wound by a coil on a non-magnetic frame without electrical connection of the ends and the transport current. Cool tape high-temperature superconductor of the second generation, folded in a stack or wound on a non magnetic frame in the form of axisymmetric or track coil, without electric connections of the ends and a transport current, behaves as a massive sample of a superconductor and the Meissner Oxenfeld effect, the magnetic field created by the magnetic rail is displaced from the volume of the superconductor, causing the power of levitation and the vehicle hangs over the track structure.
The high critical parameters of the second-generation high-temperature superconductor belt ensure efficient operation of the superconducting levitation device.
Aim: To demonstration the technical feasibility and efficiency of creating a levitation unit based on the use of a second-generation high-temperature superconductor and permanent magnets made of rare earth metals.
Methods: Calculations of the magnetic field distribution in the combination of a magnetic rail and a massive superconductor, preliminary design of the levitation unit and experimental studies on the model.
Results: Experiments on a model of a superconducting levitation device confirmed the efficiency of this technical solution and its effectiveness.
Conclusion: an original technical solution is proposed that allows to significantly improve the energy characteristics of the levitation node by using a second-generation high-temperature superconductor operating in a passive mode without a transport current, using the partial Meissner-Oxenfeld effect and the engagement of quantized magnetic flux strands at the pinning centers.
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Marchevsky, Maxim. "Quench Detection and Protection for High-Temperature Superconductor Accelerator Magnets". Instruments 5, n.º 3 (5 de agosto de 2021): 27. http://dx.doi.org/10.3390/instruments5030027.
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High-temperature superconductors (HTS) are being increasingly used for magnet applications. One of the known challenges of practical conductors made with high-temperature superconductor materials is a slow normal zone propagation velocity resulting from a large superconducting temperature margin in combination with a higher heat capacity compared to conventional low-temperature superconductors (LTS). As a result, traditional voltage-based quench detection schemes may be ineffective for detecting normal zone formation in superconducting accelerator magnet windings. A developing hot spot may reach high temperatures and destroy the conductor before a practically measurable resistive voltage is detected. The present paper discusses various approaches to mitigating this problem, specifically focusing on recently developed non-voltage techniques for quench detection.
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Bruyn, B. J. H. de, J. W. Jansen y E. A. Lomonova. "Modeling and comparison of superconducting linear actuators for highly dynamic motion". Archives of Electrical Engineering 64, n.º 4 (1 de diciembre de 2015): 559–70. http://dx.doi.org/10.1515/aee-2015-0041.
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Abstract This paper presents a numerical modeling method for AC losses in highly dynamic linear actuators with high temperature superconducting (HTS) tapes. The AC losses and generated force of two actuators, with different placement of the cryostats, are compared. In these actuators, the main loss component in the superconducting tapes are hysteresis losses, which result from both the non-sinusoidal phase currents and movement of the permanent magnets. The modeling method, based on the H-formulation of the magnetic fields, takes into account permanent magnetization and movement of permanent magnets. Calculated losses as function of the peak phase current of both superconducting actuators are compared to those of an equivalent non-cryogenic actuator.
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Shen, Tengming y Laura Garcia Fajardo. "Superconducting Accelerator Magnets Based on High-Temperature Superconducting Bi-2212 Round Wires". Instruments 4, n.º 2 (25 de junio de 2020): 17. http://dx.doi.org/10.3390/instruments4020017.
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Superconducting magnets are an invaluable tool for scientific discovery, energy research, and medical diagnosis. To date, virtually all superconducting magnets have been made from two Nb-based low-temperature superconductors (Nb-Ti with a superconducting transition temperature Tc of 9.2 K and Nb3Sn with a Tc of 18.3 K). The 8.33 T Nb-Ti accelerator dipole magnets of the large hadron collider (LHC) at CERN enabled the discovery of the Higgs Boson and the ongoing search for physics beyond the standard model of high energy physics. The 12 T class Nb3Sn magnets are key to the International Thermonuclear Experimental Reactor (ITER) Tokamak and to the high-luminosity upgrade of the LHC that aims to increase the luminosity by a factor of 5–10. In this paper, we discuss opportunities with a high-temperature superconducting material Bi-2212 with a Tc of 80–92 K for building more powerful magnets for high energy circular colliders. The development of a superconducting accelerator magnet could not succeed without a parallel development of a high performance conductor. We will review triumphs of developing Bi-2212 round wires into a magnet grade conductor and technologies that enable them. Then, we will discuss the challenges associated with constructing a high-field accelerator magnet using Bi-2212 wires, especially those dipoles of 15–20 T class with a significant value for future physics colliders, potential technology paths forward, and progress made so far with subscale magnet development based on racetrack coils and a canted-cosine-theta magnet design that uniquely addresses the mechanical weaknesses of Bi-2212 cables. Additionally, a roadmap being implemented by the US Magnet Development Program for demonstrating high-field Bi-2212 accelerator dipole technologies is presented.
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Larbalestier, David C. y Martin P. Maley. "Conductors from Superconductors: Conventional Low-Temperature and New High-Temperature Superconducting Conductors". MRS Bulletin 18, n.º 8 (agosto de 1993): 50–56. http://dx.doi.org/10.1557/s0883769400037775.
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A useful superconducting conductor must have several properties. Some of the key properties among these are illustrated by the cross section of a Nb-47wt%Ti/Cu composite (Figure 1) which was manufactured for the dipole magnets of the Superconducting Super Collider (SSC). It represents the state of the art for conventional conductor fabrication and is thus an excellent place to start in considering what is needed for any new conductor. First among the essential properties is a high critical current density (Jc); the lower limit of useful Jc is ~104 A/cm2, but really useful values lie between 105 and 106 A/cm2. The SSC conductor achieves this at fields up to 9 T at 4.2 K, the normal temperature used for magnets cooled by liquid helium.A critical second requirement is that the superconductor be paralleled by an intimately connected good normal conductor, in this case high-conductivity Cu. One function of the Cu is to stabilize the superconductor against small temperature disturbances that lead to flux jumps that could result in local quenching of superconductivity. This requirement forces the subdivision of a given cross section of the superconductor into many filaments having a maximum diameter of no more than about 50 μm, since bigger filaments store more electromagnetic energy than can safely be deposited in the filament without locally heating it above its critical temperature (Tc). One advantage of high-temperature superconducting (HTS) materials is that they can operate at temperatures above ~10 K. Since the specific heat is a strongly increasing function at low temperatures, this permits the safe filament size to greatly increase too. The need to minimize hysteresis losses, however, often provides a separate drive to minimize the filament diameter, as in the conductor of Figure 1, where there are some 7,000 filaments which are only 6 μm in diameter. The overall Cu:Nb-Ti ratio is about 1.5:1. This represents a compromise between the need to minimize the dilution of the supercurrent density by Cu and the need to provide sufficient high-conductivity normal metal to pass the current when the magnet makes the transition from the superconducting to the normal state (a quench).
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Ogitsu, Toru, Masami Iio, Naritoshi Kawamura y Makoto Yoshida. "Development of Radiation-Tolerant HTS Magnet for Muon Production Solenoid". Instruments 4, n.º 4 (12 de octubre de 2020): 30. http://dx.doi.org/10.3390/instruments4040030.
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Superconducting magnets are widely used in accelerator science applications. Muon production solenoids are applications that have recently attracted considerable public attention, after the approval of muon-related physics projects such as coherent muon to electron transition or muon-to-electron-conversion experiments. Based on its characteristics, muon production solenoids tend to be subjected to high radiation exposure, which results in a high heat load being applied to the solenoid magnet, thus limiting the superconducting magnet operation, especially for low-temperature superconductors such as niobium titanium alloy. However, the use of high-temperature superconductors may extend the operation capabilities owing to their functionality at higher temperatures. This study reviews the characteristics of high temperature superconductor magnets in high-radiation environments and their potential for application to muon production solenoids.
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Wang, Xiaorong, Stephen A. Gourlay y Soren O. Prestemon. "Dipole Magnets Above 20 Tesla: Research Needs for a Path via High-Temperature Superconducting REBCO Conductors". Instruments 3, n.º 4 (22 de noviembre de 2019): 62. http://dx.doi.org/10.3390/instruments3040062.
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To enable the physics research that continues to deepen our understanding of the Universe, future circular colliders will require a critical and unique instrument—magnets that can generate a dipole field of 20 T and above. However, today’s maturing magnet technology for low-temperature superconductors (Nb-Ti and Nb 3 Sn) can lead to a maximum dipole field of around 16 T. High-temperature superconductors such as REBCO can, in principle, generate higher dipole fields but significant challenges exist for both conductor and magnet technology. To address these challenges, several critical research needs, including direct needs on instrumentation and measurements, are identified to push for the maximum dipole fields a REBCO accelerator magnet can generate. We discuss the research needs by reviewing the current results and outlining the perspectives for future technology development, followed by a brief update on the status of the technology development at Lawrence Berkeley National Laboratory. We present a roadmap for the next decade to develop 20 T-class REBCO accelerator magnets as an enabling instrument for future energy-frontier accelerator complex.
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Rossi, Lucio y Davide Tommasini. "The Prospect for Accelerator Superconducting Magnets: HL-LHC and Beyond". Reviews of Accelerator Science and Technology 10, n.º 01 (agosto de 2019): 157–87. http://dx.doi.org/10.1142/s1793626819300093.
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Superconducting Magnets for High Energy Physics Accelerators are entering a new era. The successful operation of the LHC in the last decade has marked the summit of the Nb-Ti technology exploitation initiated by the Tevatron. Now, after two decades of development, Nb3Sn technology for accelerators is becoming mature and the construction of the high luminosity LHC (HL-LHC) magnets will be the most tangible sign of the new phase, with magnets that will operate well beyond the symbolic threshold of 10 T. In addition, 30 years after its discovery, the high temperature superconductors (HTSs) for accelerator magnets are under development and test, to understand if these materials can enable the 20 T range for next accelerator/colliders foreseen after 2030. The paper reviews the main issues and the criticalities of the magnets’ development for the next future project, HL-LHC, and gives the prospect for the design and technological effort that is underway in magnet technology for the energy Frontier (FCC/HE-LHC).
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Choi, Yojong, Junseong Kim, Geonwoo Baek, Seunghak Han, Woo Seung Lee y Tae Kuk Ko. "Measurement of Magnetic Field Properties of a 3.0 T/m Air-Core HTS Quadrupole Magnet and Optimal Shape Design to Increase the Critical Current Reduced by the Incident Magnetic Field". Electronics 9, n.º 3 (7 de marzo de 2020): 450. http://dx.doi.org/10.3390/electronics9030450.
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Air-core high-temperature superconducting quadrupole magnets (AHQMs) differ from conventional iron-core quadrupole magnets, in that their iron cores are removed, and instead high-temperature superconductors (HTSs) are applied. The high operating temperature and high thermal stability of HTS magnets can improve their thermodynamic cooling efficiency. Thus, HTS magnets are more suitable than low temperature superconducting magnets for withstanding radiation and high heat loads in the hot cells of accelerators. AHQMs are advantageous because they are compact, light, and free from the hysteresis of ferromagnetic materials, due to the removal of the iron-core. To verify the feasibility of the use of AHQMs, we designed and fabricated a 3.0 T/m AHQM. The magnetic field properties of the fabricated AHQM were evaluated. Additionally, the characteristics of the air-core model and iron-core model of 9.0 T/m were compared in the scale for practical operation. In comparison with the iron-core model, AHQM significantly reduces the critical current (IC) due to the strong magnetic field inside the coil. In this study, a method for the accurate calculation of IC is introduced, and the calculated results are compared with measured results. Furthermore, the optimal shape design of the AHQM to increase the critical current is introduced.
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Bottura, Luca y Arno Godeke. "Superconducting Materials and Conductors: Fabrication and Limiting Parameters". Reviews of Accelerator Science and Technology 05 (enero de 2012): 25–50. http://dx.doi.org/10.1142/s1793626812300022.
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Superconductivity is the technology that enabled the construction of the most recent generation of high-energy particle accelerators, the largest scientific instruments ever built. In this review we trace the evolution of superconducting materials for particle accelerator magnets, from the first steps in the late 1960s, through the rise and glory of Nb–Ti in the 1970s, till the 2010s, and the promises of Nb3Sn for the 2020s. We conclude with a perspective on the opportunities for high-temperature superconductors (HTSs). Many such reviews have been written in the past, as witnessed by the long list of references provided. In this review we put particular emphasis on the practical aspects of wire and tape manufacturing, cabling, engineering performance, and potential for use in accelerator magnets, while leaving in the background matters such as the physics of superconductivity and fundamental material issues.
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Muralidhar, Miryala, Kazuo Inoue, Michael R. Koblischka y Masato Murakami. "Fabrication of MgB2 Bulk Magnets with High Critical Currents". Advances in Science and Technology 95 (octubre de 2014): 196–201. http://dx.doi.org/10.4028/www.scientific.net/ast.95.196.
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We report on the fabrication and characterization of disk-shaped bulk MgB2 superconductors with high performance as superconducting bulk magnets. Several samples of diameters 20 mm, 30 mm and 40 mm were fabricated using a solid state reaction in pure Ar atmosphere at 775°C for 3h. The magnetization measurements confirmed that all the samples exhibited a sharp superconducting transition with Tc(onset) at around 38.5 K. The samples showed respective critical current density (Jc) values of 176 kA cm-2 and 55 kA cm-2 at 20 K in self field and 1T. The Jc values increased further to 250 kA cm-2 and 100 kA cm-2 with decreasing temperature down to 10 K. MgB2 samples 20 mm and 30 mm in diameter and 7 mm in thickness exhibited trapped field values of 1.15 T and 1.3 T at 25 K, respectively. Microstructural observations with scanning electron microscopy (SEM) revealed that the samples are highly porous. And hence, continuing development of large-sized bulk MgB2 with higher density will lead to promising industrial applications.
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Hellstrom, Eric E. "Important Considerations for Processing Bi-Based High-Temperature Superconducting Tapes and Films for Bulk Applications". MRS Bulletin 17, n.º 8 (agosto de 1992): 45–51. http://dx.doi.org/10.1557/s0883769400041853.
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High-temperature superconductors are brittle oxide ceramics, yet they have been made into wire that has been wrapped into solenoids and used in demonstration magnets and motors. Fabricating wires from these ceramics is an extremely challenging materials science process that requires a precisely engineered microstructure with the correct chemical, mechanical, and electromagnetic properties if these wires are to transport large current densities (Jc) in high magnetic fields. Heine et al. first demonstrated that wires of these materials could carry high Jc in very high magnetic fields. At 4.2 K, the oxide superconducting wires can carry higher Jc at higher magnetic fields than conventional Nb-Ti or Nb3Sn wires (Figure 1), and as shown in the companion article in this issue by Kato et al. they can also have high Jc at 77 K.Of the three major families of high-temperature superconductors, YBa2Cu3O7-x, Bi-Sr-Ca-Cu-O (BSCCO), and Tl-Ba-Ca-Cu-O, the best wires to date have been made in the BSCCO system. At present, all YBa2Cu3O7-x wires are weak linked and have only small Jc in magnetic fields. In the Tl-based system, the superconducting properties are potentially very interesting, but the toxicity of Tl and the system's complex processing have limited conductor development. For the Bi-based system, the basic processing steps are becoming known, the grains are well connected, and the weak link problem can be controlled. This permits applications in the temperature range 4–77 K, depending on the field and current density requirements of the particular use.
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WEBER, HARALD W. "RADIATION EFFECTS ON SUPERCONDUCTING FUSION MAGNET COMPONENTS". International Journal of Modern Physics E 20, n.º 06 (junio de 2011): 1325–78. http://dx.doi.org/10.1142/s0218301311018526.
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Nuclear fusion devices based on the magnetic confinement principle heavily rely on the existence and performance of superconducting magnets and have always significantly contributed to advancing superconductor and magnet technology to their limits. In view of the presently ongoing construction of the tokamak device ITER and the stellerator device Wendelstein 7X and their record breaking parameters concerning size, complexity of design, stored energy, amperage, mechanical and magnetic forces, critical current densities and stability requirements, it is deemed timely to review another critical parameter that is practically unique to these devices, namely the radiation response of all magnet components to the lifetime fluence of fast neutrons and gamma rays produced by the fusion reactions of deuterium and tritium. I will review these radiation effects in turn for the currently employed standard "technical" low temperature superconductors NbTi and Nb 3 Sn , the stabilizing material ( Cu ) as well as the magnet insulation materials and conclude by discussing the potential of high temperature superconducting materials for future generations of fusion devices, such as DEMO.
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Antonov, Yuri F. "Calculation, design and manufacture of heteropolar magnetic levitation and linear drive systems of maglev transport". Transportation Systems and Technology 7, n.º 2 (1 de julio de 2021): 119–29. http://dx.doi.org/10.17816/transsyst202172119-129.
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Background: The methods of calculation and elements of the technology for creating heteropolar magnetic systems of levitation, lateral stabilization and a rotor-runner of a traction linear synchronous motor for the development of the transport technology "Russian Maglev" in order to achieve an increased levitation gap of 0.2 m, reduce the threshold speed of the exit vehicle in levitation mode up to 10 km/h.
Aim: to develop methods for calculating and designing heteropolar poles from elementary permanent magnets, coils of the same type based on composite low-temperature superconductors and high-temperature tape superconductors of the second generation and a step-by-step technology for their production.
Tasks:
Creation of an on-board magnetic system of levitation and lateral stabilization, allowing to provide a levitation gap of 0.2 m, a threshold value of vehicle speed of 10 km/h when transition to levitation mode, to reduce stray magnetic fields to the level of the natural field of terrestrial magnetism of 50 T;
Creation of a rotor-runner of a linear synchronous motor with an ironless stator with a power of 10 MW.
Methods: outlines the main calculation methodologies: "analysis" and "synthesis". The "analysis" methodology is adopted in solving the "direct" calculation problem, when the configuration of the magnetic system is set and the magnetic field in the working area is calculated, and, if necessary, the stray magnetic fields. This methodology can be effectively applied if there is experience in creating magnetic systems. Otherwise, the "synthesis" methodology is applied, which is used in solving the "inverse" calculation problem, in which the picture of the distribution of the magnetic field in the working zone is set and the configuration of the magnetic system is found (synthesized).
Results of the study performed:
The parameters and characteristics of high-energy permanent magnets made of rare-earth metals, low-temperature and high-temperature superconducting winding materials have been analyzed, the choice of permanent magnets and superconducting winding material has been made;
Calculations of the magnetic system of permanent magnets in the "Halbach assembly" and in the traditional assembly in a toothed ferromagnetic core have been carried out;
Calculations of a track coil with a rectangular cross-section of the winding are performed;
Methods for calculating and optimizing superconducting magnetic systems from a set of similar track modules have been developed;
Conclusions: The results of the performed fundamental research will allow starting the calculation, design and construction of conveyor-main passenger and freight lines of maglev transport, as well as urban public transport.
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Brown, Alan S. "Maglev Goes to Work". Mechanical Engineering 128, n.º 06 (1 de junio de 2006): 39–41. http://dx.doi.org/10.1115/1.2006-jun-4.
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This article discusses various features of a mixer that proves to be advantageous for pharmaceutical market. Central Japan Railway Co. has tested the first-ever maglev train using high-temperature superconductors; the technology that is still a long way from practical commercialization. Instead, LevTech Inc., a Lexington, Ky., startup is using yttrium-barium-copper oxide superconductors to suspend impellers in mixers and pumps for the bioprocessing and pharmaceutical industry. The LevTech mixer's cassette holds six superconducting magnets, which suspend and lock into place an impeller that can be isolated in a pre-sterilized mixing bag. Rotating the cassette turns the impeller, which stirs the biochemicals inside the sealed bag. According to JR Central, superconductors have certain advantages over conventional electromagnets. First, they are much lighter. This improves railcar acceleration, speed, and payload; they also use less energy and more importantly, though, their 1 Tesla magnetic fields can lift a train 3 to 4 inches off the track, compared to 0.3 to 0.4 inch achieved with ordinary electromagnets.
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Stephan, Richard, Felipe Costa, Elkin Rodriguez y Zigang Deng. "Retrospective and perspectives of the superconducting magnetic levitation (sml) technology applied to urban transportation". Transportation Systems and Technology 4, n.º 3 suppl. 1 (19 de noviembre de 2018): 195–202. http://dx.doi.org/10.17816/transsyst201843s1195-202.
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A review of the Superconducting Magnetic Levitation (SML) technology applied to urban transportation will be presented. The historical time line will be highlighted, pointing out the pioneering efforts at Southwest Jiatong University (SWJTU), China, followed by the Supra Trans project in IFW-Dresden, Germany, and the MagLev-Cobra project in UFRJ, Brazil.
Background: Details of the MagLev-Cobra project, the first, and until today the single one, applying the SML technology that counts with a real scale prototype, operating regularly in open air, will be disclosed. The inauguration of the MagLev-Cobra project was on the 1st October 2014, the last day of the “22nd International Conference on Magnetically Levitated Systems and Linear Drives (MAGLEV)” held in Rio de Janeiro. Curiously, this day coincides with the 50th anniversary of the successful operation of the Shinkansen in Tokyo. On the 1st October 1964, the first high-speed wheel and rail train in the world was inaugurated in time for the first Olympic Games that took place in Asia. This historical coincidence is a good omen for the MagLev-Cobra project. In fact, since October 2014, the system operates regularly for demonstration at the UFRJ Campus, every Tuesday. More than 12.000 visitors have already had the opportunity to take a test ride.
Aim: The Proceedings of the MAGLEV conferences, which first edition dates back to 1977 (http://www.maglevboard.net), are the documentary files of the importance of this achievement. Initially, the methods named Electromagnetic Levitation (EML) and Electrodynamic Levitation (EDL) were considered.
Methods: At the end of last century, due to the availability of Rare Earth Permanent Magnets and High Critical Temperature Superconductors (HTS), an innovative levitation method, called Superconducting Magnetic Levitation (SML), started to be considered. This method is based on the flux pinning effect property of HTS in the proximity of magnetic fields given by rare earth permanent magnets. The first experiments with SML, as expected, were small scale prototypes, or laboratory vehicles for one, two or four passengers, proposed mainly by researchers from Germany, China and Brazil. The Proceedings of the 16th MAGLEV, held in year 2000, confirms this fact. After 14 years of research and development, the team of the Laboratory of Applied Superconductivity (LASUP) of UFRJ achieved the construction of the first real scale operational SML vehicle in the world.
Results: This retrospective will be followed by a comparison with the EML technology, that has already four urban commercial systems, will be presented and the application niches delimited.
Conclusion: The perspectives of the MagLev-Cobra project and the cooperation efforts with China to turn it a commercial experience will finish the paper. As will be explained, before the commercial application of the MagLev-Cobra technology, the system must be certified and the technical, economic and environmental viability for a first deployment concluded.
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Branch, Paul, Yeekin Tsui, Kozo Osamura y Damian P. Hampshire. "Weakly-Emergent Strain-Dependent Properties of High Field Superconductors". Scientific Reports 9, n.º 1 (30 de septiembre de 2019). http://dx.doi.org/10.1038/s41598-019-50266-1.
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Abstract All superconductors in high field magnets operating above 12 T are brittle and subjected to large strains because of the differential thermal contraction between component parts on cool-down and the large Lorentz forces produced in operation. The continuous scientific requirement for higher magnetic fields in superconducting energy-efficient magnets means we must understand and control the high sensitivity of critical current density Jc to strain ε. Here we present very detailed Jc(B, θ, T, ε) measurements on a high temperature superconductor (HTS), a (Rare−Earth)Ba2Cu3O7−δ (REBCO) coated conductor, and a low temperature superconductor (LTS), a Nb3Sn wire, that include the very widely observed inverted parabolic strain dependence for Jc(ε). The canonical explanation for the parabolic strain dependence of Jc in LTS wires attributes it to an angular average of an underlying intrinsic parabolic single crystal response. It assigns optimal superconducting critical parameters to the unstrained state which implies that Jc(ε) should reach its peak value at a single strain (ε = εpeak), independent of field B, and temperature T. However, consistent with a new analysis, the high field measurements reported here provide a clear signature for weakly-emergent behaviour, namely εpeak is markedly B, (field angle θ for the HTS) and T dependent in both materials. The strain dependence of Jc in these materials is termed weakly-emergent because it is not qualitatively similar to the strain dependence of Jc of any of their underlying component parts, but is amenable to calculation. We conclude that Jc(ε) is an emergent property in both REBCO and Nb3Sn conductors and that for the LTS Nb3Sn conductor, the emergent behaviour is not consistent with the long-standing canonical explanation for Jc(ε).
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Paz-Soldan, C. "Non-planar coil winding angle optimization for compatibility with non-insulated high-temperature superconducting magnets". Journal of Plasma Physics 86, n.º 5 (octubre de 2020). http://dx.doi.org/10.1017/s0022377820001208.
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The rapidly emerging technology of high-temperature superconductors (HTS) opens new opportunities for the development of non-planar non-insulated HTS magnets. This type of HTS magnet offers attractive features via its simplicity and robustness, and is well suited for modest size steady-state applications such as a mid-scale stellarator. In non-planar coil applications the HTS tape may be subject to severe hard-way bending strain ( $\epsilon _{\textrm {bend}}$ ), torsional strains ( $\epsilon _{\textrm {tor}}$ ) and magnetic field components transverse to the HTS tape plane ( $B_{\perp }$ ), all of which can limit the magnet operating space. A novel method of winding angle optimization is here presented to overcome these limitations for fixed input non-planar coil filamentary geometry. Essentially, this method: (i) calculates the peak $\epsilon _{\textrm {bend}}$ and $B_{\perp }$ for arbitrary winding angle along an input coil filamentary trajectory, (ii) defines a cost function including both and then (iii) uses tensioned splines to define a winding angle that reduces $\epsilon _{\textrm {tor}}$ and optimizes the $\epsilon _{\textrm {bend}}$ and $B_{\perp }$ cost function. As strain limits are present even without $B_{\perp }$ , this optimization is able to provide an assessment of the minimum buildable size of an arbitrary non-planar non-insulating HTS coil. This optimization finds that for standard 4 mm wide HTS tapes the minimum size coils of the existing HSX, NCSX and W7-X stellarator geometries are around 0.3–0.5 m in mean coil radius. Identifying the minimum size provides a path to specify a mid-scale stellarator capable of achieving high-field or high-temperature operation with minimal HTS tape length. For coils larger than this size, strain optimization allows use of wider (higher current capacity) HTS tapes or alternatively permitting a finite (yet tolerable) strain allows reduction of $B_{\perp }$ . Reduced $B_{\perp }$ enables a reduction of the HTS tape length required to achieve a given design magnetic field or equivalently an increase in the achievable magnetic field for fixed HTS tape length. The distinct considerations for optimizing a stellarator coilset to further ease compatibility with non-insulated HTS magnets are also discussed, highlighting relaxed curvature limits and the introduction of limits to the allowable torsion.
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Leveratto, A., A. Angrisani Armenio, A. Traverso, G. De Marzi, G. Celentano y A. Malagoli. "Transport current and magnetization of Bi-2212 wires above liquid Helium temperature for cryogen-free applications". Scientific Reports 11, n.º 1 (3 de junio de 2021). http://dx.doi.org/10.1038/s41598-021-91222-2.
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AbstractSince the discovery of high temperature superconductors, a possible cryogen-free scenario has always been wished. Nowadays, liquid Helium is running out, and it is likely that the cooling by will be a large part of the costs of any superconducting system. Bi-2212 wires at temperature higher than 4.2 K still show a very high irreversibility field and thus a deep investigation of their properties in such a range of temperature is very useful in order to assess the applicability in high field cryogen-free magnets. Here electrical transport and magnetic properties characterization at variable temperature and magnetic field on our “GDG—processed” wires are reported together with a well-described original approach to calculate the irreversibility field Hirr. This study is devoted to provide reference data on the behaviour of the only isotropic wire for high field application with an eye to the performances at temperatures above 4.2 K.
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"Effect of Substrate Layer Thickness on the AC Losses in Stacked Superconducting Pancake Coils using Direct H-formulations". International Journal of Engineering and Advanced Technology 9, n.º 1S3 (31 de diciembre de 2019): 150–54. http://dx.doi.org/10.35940/ijeat.a1030.1291s319.
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Advanced electric aircrafts are in their design phase and superconducting machines are going to be the part of such fascinating technology. In order to diminish the losses involved due to conventional copper conductors, superconductors are proposed for the electric aircraft applications by the American research agencies like NASA and AFRL. Usually, Pancake coils are frequently used in various electric aircraft power applications including high speed motors, generators, transformers and solenoid magnets. Coils are generally bound with high temperature superconducting (HTS) tapes like BSCCO and YBCO. Mostly, 2nd generation coated conductors (YBCO) are employed in power applications due to their merits over BSCCO (1st generation tapes). A superconducting tape manufactured by SuperPower through iBAD manufacturing technique generally consist copper stabilizer, silver over-layer, YBCO layer, buffer layer, substrate material followed by copper stabilizer. The volume fraction of the substrate material and copper stabilizer is more than 90% in the proposed tape. In the present work, the thickness of the substrate material has been varied to evaluate the AC losses involved in the above mentioned applications due to time-varying magnetic fields. A current of 270 A (Ic=330 A) is flowing through a coil of 108 turns. AC loss has been evaluated for various thicknesses 30 µm to 90 µm at a frequency of 50 Hz. The simulations are done using COMSOL MultiPhysics® commercial software package.
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Kerchner, H. R., C. Cantoni, M. Paranthaman, D. K. Christen, H. M. Christen, J. R. Thompson y D. J. Miller. "Heavy-Ion Damage to Magnesium Diboride Films: Electrical Transport-Current Characterization". MRS Proceedings 689 (2001). http://dx.doi.org/10.1557/proc-689-e.5.5.
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ABSTRACTThe use of magnesium diboride in superconducting magnets, transmission lines, or other large-scale applications depends on the transport-current characteristics of this material in magnetic field, and how they compare to the properties of conventional and high-temperature superconductors. Thin films of boron grown on sapphire substrates during electron-beam evaporation were exposed to Mg vapor to produce 0.5-μm thick layers of the metallic compound MgB2. Four-terminal measurements of their voltagecurrent relations, E(J), were carried out before and after exposure to Bφ =1-T and higher doses of 1-Gev U ions. These doses lowered critical temperatures Tc≈39 K less than 0.1 degree, raised the normal-state resistivity, and reduced the loss-free critical current density, Jc. Higher doses added little. The reduction of current densities was greater in the presence of applied magnetic field greater than 0.1 T.
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Creely, A. J., M. J. Greenwald, S. B. Ballinger, D. Brunner, J. Canik, J. Doody, T. Fülöp et al. "Overview of the SPARC tokamak". Journal of Plasma Physics 86, n.º 5 (29 de septiembre de 2020). http://dx.doi.org/10.1017/s0022377820001257.
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The SPARC tokamak is a critical next step towards commercial fusion energy. SPARC is designed as a high-field ( $B_0 = 12.2$ T), compact ( $R_0 = 1.85$ m, $a = 0.57$ m), superconducting, D-T tokamak with the goal of producing fusion gain $Q>2$ from a magnetically confined fusion plasma for the first time. Currently under design, SPARC will continue the high-field path of the Alcator series of tokamaks, utilizing new magnets based on rare earth barium copper oxide high-temperature superconductors to achieve high performance in a compact device. The goal of $Q>2$ is achievable with conservative physics assumptions ( $H_{98,y2} = 0.7$ ) and, with the nominal assumption of $H_{98,y2} = 1$ , SPARC is projected to attain $Q \approx 11$ and $P_{\textrm {fusion}} \approx 140$ MW. SPARC will therefore constitute a unique platform for burning plasma physics research with high density ( $\langle n_{e} \rangle \approx 3 \times 10^{20}\ \textrm {m}^{-3}$ ), high temperature ( $\langle T_e \rangle \approx 7$ keV) and high power density ( $P_{\textrm {fusion}}/V_{\textrm {plasma}} \approx 7\ \textrm {MW}\,\textrm {m}^{-3}$ ) relevant to fusion power plants. SPARC's place in the path to commercial fusion energy, its parameters and the current status of SPARC design work are presented. This work also describes the basis for global performance projections and summarizes some of the physics analysis that is presented in greater detail in the companion articles of this collection.