Use Of High Temperature Superconductors Research Articles

Разработка и применение самолетов с тяговыми электродвигателями как перспективный тренд развития современной авиации: опыт КНР

The purpose of this article is to review the development and use of aircraft with traction electric motors based on the experience of the People's Republic of China. Examples from the end of the XIX century to the present day are considered. The possibilities of cooperation between the two countries in the area of development and application of aircraft with traction electric motors are proposed, by increasing the efficiency of EMs and reducing their weight through the use of high-temperature superconductors that transition to a state of superconductivity at a temperature provided by liquid nitrogen at the level of 70–90 K.

Exploring Fcc-ee Optics Designs with Combined Function Magnets

The FCC-ee project takes a step forward towards the discovery of new physical phenomena beyond the frontier of the standard model, by aiming at unprecedented center of mass energies and luminosities in a double-ring lepton collider. In order to explore potential improvements to the current lattice design, this paper examines the use of combined function magnets within the short straight sections of the arc cells. The use of High Temperature Superconductors (HTS) with an operating temperature of 12 K and maximum field of 18.2 T for the combined function magnets allows increasing the bending radius and decreasing the synchrotron radiation. A first design is presented with comparisons to the current baseline.

High-Temperature Superconducting Undulator Prototype Coils for Compact Free-Electron Lasers

Short-period and high-field undulators are crucial for the production of coherent light up to X-rays in compact free-electron lasers (FELs). Besides, future colliders like CLIC or FCC-ee demand high-field damping wigglers to reach a low beam emittance. Both applications may benefit from the use of high-temperature superconductors (HTS), e.g. by providing high magnetic field amplitudes or higher operating temperatures. This paper presents and summarizes our HTS undulator prototype coils, designed and manufactured at CERN, made from coated REBCO tape superconductor. The coil design, described and already powered at 77K in previous works, is based on no-insulation (NI) vertical racetracks with a period length of 13 mm, assembled with iron poles. Powering tests of several HTS undulator prototype coils at 4.2 K, performed at KIT, revealed safe operations at high engineering current densities of 2.3 kA/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> with produced magnetic fields of up to 1.5 T at 3.5mm distance from the magnetic iron poles. Reasonable effective time constants of around 100 s were obtained and further powering tests in regions beyond <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</i> c with 3.6 kA/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> showed the stability of our NI design and created magnetic fields in the region of 2 T.

Cryogenic System Infrastructure for a Tokamak Based on Reactor Technologies

The article describes the purpose of developing a new line for construction of tokamaks within the framework of the Federal Project FP-3 as part of the integrated program “Development of equipment, technologies and scientific research in the field of nuclear energy use in the Russian Federation for the period up to 2024” (RTTN) is described. The main feature of the installation designed within the framework of RTTN is the use of high-temperature superconductors for the electromagnetic system, for which a developed and highly reliable cryogenic infrastructure shall be set up. The main elements of this system are described, and its technical parameters are given. The system, which is under development, will ensure the helium and nitrogen flowrates necessary to maintain the required TRT tokamak operation mode.

Review of High Power and High Voltage Electric Motors for Single-Aisle Regional Aircraft

This paper presents a review of the state of the art in electric propulsion for regional aircraft in the MW range. The implications surrounding the implementation of this technology, such as the need of high-power density or the use of high-voltage at high-altitude, are presented. Along with the challenges, the available technologies to face them are reviewed. Those are, as follows, the emerging new motor topologies for this purpose, the winding technologies, the materials employed for electric motors for aircraft propulsion and the ground-breaking use of high-temperature superconductors (HTS) as a high-power density enabler. Finally, a conclusion is presented gathering the main ideas of the paper.

Design of the First HTS Single-Coil Demonstrator of GaToroid Toroidal Gantry for Hadron Therapy

The design and construction of compact and lightweight gantries for hadron therapy are essential steps toward wider accessibility to this cancer treatment. The use of a high-field steady-state toroidal gantry, i.e., GaToroid, represents an attractive alternative to the state-of-the-art with the potential of significantly reducing size and weight of present installations. It is interesting to conceive the use of High-Temperature Superconductors (HTS) conductors to reach magnetic fields beyond 8 T at relatively high temperatures, decreasing the beam bending radius and, at the same time, avoiding complex cryogenics systems in the hospitals. The construction of such a machine requires several steps of prototyping and this manuscript presents the design of the first GaToroid single-coil demonstrator, wound with ReBCO conductors. The demonstrator is a scaled version of a full-scale GaToroid coil, with the conductors spaced into four planar windings, i.e., grades, and wound as a double pancake. Two operating regimes are foreseen to test the demonstrator at different temperatures, currents and magnetic fields. The cable geometry, composed of four ReBCO non-twisted tapes, was validated through 1D quench propagation studies in both regimes, and the hot spot temperature is well below 100 K. Furthermore, three-dimensional mechanical simulations allowed to estimate the stress state on the conductor, as well as to define the impregnation strategy of the demonstrator. The answers provided by the manufacturing, powering and test of the proposed demonstrator can provide valuable insights for the future construction of full-scale GaToroid coils.

Development of Radiation-Tolerant HTS Magnet for Muon Production Solenoid

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.

Quench detection using Hall sensors in high-temperature superconducting CORC®-based cable-in-conduit-conductors for fusion applications

Advanced magnet systems for fusion applications would greatly benefit from the use of high-temperature superconductors (HTS). These materials allow fusion magnets to operate at higher magnetic fields, allowing for more compact fusion machines, and allow for operation at elevated temperatures, enabling demountable coils that provide access for maintenance of the fusion reactor. Quench detection remains a major challenge in the protection of HTS magnets that are vulnerable to localized conductor burnout due to their low quench propagation velocities. One of the methods explored is the use of Hall sensors that are incorporated in or near the magnet terminations that can detect local field variations that occur as a result of current redistribution within the conductor to bypass a hotspot within the magnet winding. This method is potentially well suited for Cable in Conduit Conductors, such as those made from Conductor on Round Core (CORC) cables, in which sub-cables containing HTS tapes are connected to the terminations at a low resistance. To demonstrate the technique, a CORC® triplet consisting of three sub-cables, rated for 4 kA operation at 77 K, was manufactured and Hall sensors were used to measure local field variations next to the terminations due to current redistribution between the cables. The Hall response was compared to voltages that developed over the cables and terminations as a local hotspot was applied to different cables in the triplet. It was found that the Hall sensors were faster and more sensitive than voltage contact measurements and were able to reliably detect current redistribution of only a few amperes caused by a hotspot, well before the triplet exceeded its critical current. The method also allowed the detection of heater-induced hotspots during high ramp rates of 2 kA s−1 relevant for fusion applications. Hall sensors have a distinct benefit of being less sensitive to inductive pickup of AC interference compared to voltage contact measurements that make quench detection through voltage measurements in magnets especially challenging. The method can also be used for diagnostic measurements of current redistribution caused by other sources such as inhomogeneous current injection from faulty joints, or localized conductor damage. The Hall sensors are likely capable of detecting the onset of a quench that may occur a far distance away from the sensor location, presenting a breakthrough in HTS quench detection that potentially removes one of the remaining barriers to reliable operation of large HTS magnet systems.

Self-Protecting HTS Current Lead-Demonstration of a New Technology

A straight forward solution to reduce the heat load of Current Leads to superconducting magnets operating at 4 K is the use of high temperature superconductors (HTS) thereby eliminating the ohmic heating at the range below 50–77 K. The heat input from the current leads is then determined by heat conduction in the HTS section only, leading to some factor 10 reduction in the heat load in comparison to fully normal conducting conventional leads. Modern HTS conductors demonstrate extremely high current density and further decrease of the current lead heat load is limited not by the material properties but by the requirement of robustness and reliable protection of the leads in the case of cryogenic failures in order to avoid lead burnout. While accelerator magnets are designed for a fast dump at quench events within a fraction of a second, larger stored energy magnets like detector magnets may have discharge times of tens of seconds or even more. In this case the HTS part of the lead has to withstand the ohmic heating for a relatively long time and this requirement then determines the heat input at operation conditions. A new idea to reduce the heat load while keeping full reliability of the HTS leads is using a thermo-mechanical switch that is connected electrically in parallel to the HTS lead section. In the case of a quench in the HTS lead section, by using the differential thermal expansion between materials, the switch turns on and the overheated section is bypassed by the high cross-section of the conductive part of the switch. We wish to use this new technology for the first time for the BabyIAXO detector magnet. In this paper the design and test of the first and unique Self-Protecting HTS Current Lead with a current rating of 800 A is presented.

A Proposal for a Superconducting Space Magnet for an Antimatter Spectrometer

Future spaceborne spectrometers for astroparticle detection need high bending power therefore, the use of superconducting magnets is the sole applicable solution. Space magnets require high reliability that, in turn, requires high stability. Avoiding liquid helium cryogenics is also an attractive feature. The use of high temperature superconductors (HTS) or magnesium diboride (MgB2) combines both the requirements. The paper describes an HTS magnet operating at about 30 K that will be one of the main components of a space antimatter spectrometer. The magnet is a large toroid that will host a silicon tracker inside its internal volume and a 3D isotropic calorimeter in the center. The inner and outer diameters are 1 m and 4.3 m, respectively. The magnet mass is about 1200 kg.

Analysis application possibilities of high-temperature superconductors in electric networks

In the article the technical analysis of existing constructive decisions concerning use of high-temperature superconducting cables is carried out. The features of the use of superconductors in electrical distribution networks are analyzed. The advantages of using high-temperature superconductors in comparison with low-temperature superconductors are established. It is determined that the use of high-temperature superconductors, due to the increased critical parameters, provides an increase in the power of transmission lines and energy saving. From the analysis it follows that high-temperature superconductor wires of 2G generation have better operational characteristics, respectively, their use is more efficient compared to wires of 1G generation. A scheme of a three-phase high-temperature superconducting power transmission network with a neutral wire is considered. The working conditions of a three-phase power network with high-temperature superconducting cables are analyzed. It is determined that the use of two cores of a high-temperature superconducting cable of a distributed power transmission system provides an increase in the throughput of electric power in distribution electric networks. Accordingly, the efficiency of electric power transmission is increased, as well as the loss of AC power and operating costs are reduced. It is shown that the use of the reactor reduces the requirements for protection devices, facilitates the operation of electrical installations, including generators of power plants, and also reduces the cost of distribution networks equipment. It is indicated that the smallest power loss in a three-phase distributed power transmission system using high-temperature superconducting cables can be achieved with a symmetrical load operation mode. The results of technical analysis can be used to develop recommendations for improving the characteristics of cable power lines.

Stable Overload Operation of High-Temperature Superconductor Protective Resistors

The use of high-temperature superconductor (HTS) resistors to protect electrical equipment and ac networks from emergency short-circuit currents and single phase-to-ground faults has been considered. It has been proposed to use a stable overload operation in HTS composite wires to enhance the speed of response and thermal stability of HTS current-limiting devices. Design solutions for the use of stabilized low-resistance HTS wires in protective resistors for ac networks have been developed that increase the resistance inserted in the circuit by several orders of magnitude. The characteristics of first-generation HTS wires with high critical parameters in the resistive state have been measured in a wide current overload range. Prototypes of instantaneous thermally stable current-limiting devices with HTS protective resistors have been fabricated and tested. The design parameters of HTS protective resistors for use in electric power networks have been calculated.

High Temperature Superconductor-Based Technologies as Enabler for Efficient and Resilient Energy Systems

New technologies based on the use of High Temperature Superconductors (HTS) can lead to higher efficiency and more resilient energy systems. HTS applications are creating unique opportunities for promising commercial components that can enable the needed evolution of the energy system, such as high-capacity power cables, fault current limiters, high-efficiency generators for offshore wind turbines, energy storage, and innovative transformers. Not only do superconductor-based devices provide improvements over conventional electric grid technologies, they also offer unique alternatives to system challenges that cannot be addressed otherwise. This paper, developed by the International Energy Agency's Technology Collaborative Program on High Temperature Superconductivity, will explore the potential capabilities of HTS-based devices to advance the transformation of today's energy systems toward more a reliable, resilient, secure, affordable, flexible, and efficient regime.

Thermally Activated ReBCO Switches for Charging High-Current Magnets

Aiming at design improvements for the International Axion Observatory, alternative options for powering of the 20-kA magnet are under consideration. Use of high-Temperature superconductors in a transformer-rectifier system cooled by a single stage cryocooler at 40 K-50 K level is a promising option, which allows to avoid massive movable bus bars, current leads, and related services. The overall efficiency of such a magnet powering system is determined by the characteristics of high-current switches, which have to operate in a fast synchronous manner. We studied the performance of thermally activated superconducting switches made of adjusted 4-mm-wide ReBCO tapes, using etching of the tapes in a FeCl-3 bath to increase their resistance in normal state and to prepare low-mass heaters perfectly matching the tape surface. First experimental results on the 'off' state performance and time constants of the switches, when toggling between 'on' and 'off' states, are presented. Finally, we discuss a conceptual design of an all-ReBCO rectifier system comprising a superconducting transformer and thermally activated switches, which can be scaled up for charging large magnet systems like particle detector magnets where slow charging is feasible.

The use of high temperature superconductor bulk in a co-axial magnetic gear

The torque transmission and angular speed change in machine mechanisms are provided by mechanical gear systems. Recent advances in magnetic system designs, developments in quality of the permanent magnetic and ferromagnetic materials led to possibilities of replacing magnetic gears with their mechanical counterparts. Magnetic gears are free from damages during the overloaded operation since they have no physical contact. However, the torque density in magnetic gears is lower compared to mechanical gears due to the limited magnetic flux densities of the permanent magnets. In this respect, the design alternatives are important from the point of enhancing the torque density in the magnetic gear development. For the design considerations in this paper, the effect of the gear depth on the torque efficiency and the use of high temperature superconductors in the pole pieces are investigated. The finite element analysis performed in COMSOL indicated that the torque values established on the rotors of the magnetic gear increased with increasing the depth without changing the efficiency of the gear mechanism. It was also determined that the use of superconductor in the pole pieces increased the torque transfer. High ripple on the amplitude of the torque values suggests the necessity of the experimental verification and more advance analysis.

A Fast Quench Protection System for High-Temperature Superconducting Magnets

For reaching very high magnetic fields in fully superconducting magnets, beyond 16 T for particle accelerators dipoles and beyond 23 T for solenoids, the use of high-temperature superconductors (HTS) is unavoidable. Due to the high minimum quench energy in HTS these coils are much more difficult to protect against quenches using conventional methods, such as quench heaters or coupling loss induced quench (CLIQ). Although it is possible to use a dump resistor on a short HTS magnet, extracting the energy externally, this does not provide a solution for longer magnets or magnets operated in a string, because the extraction voltage becomes unacceptably high. Here, a method named E 3 SPreSSO (External Energy Extraction Symbiotic Protection System for Series Operation) is proposed that allows for fast energy extraction in HTS magnets. The E 3 SPreSSO comprises of units with a near-zero self-inductance superconducting circuit, connected in series with the main magnet. When the protection is triggered, these devices are turned resistive, using quench heaters, overcurrent or CLIQ, causing them to absorb the energy of the system. The units can be located outside the main magnet and do not generate magnetic field. Therefore, it is possible to use relatively cost-efficient and robust Nb-Ti or possibly MgB 2 (at higher temperatures). This paper introduces the concept and provides an analytical method weighing the different options for designing the E 3 SPreSSO units themselves.

Exploring a broad spectrum of design options for DEMO

In the pursuit of realistically achievable design options for demonstrating fusion electricity generation and tritium self-sufficiency in a device to follow ITER, it is vital to explore as fully as possible the available design space and technology options which might lead to a fusion power plant within the timescales envisioned by the EU Roadmap to Fusion Energy. The usual tool for exploring this space is a systems code, such as PROCESS, which seeks to model all important plant systems and physics to provide an integrated power plant design point. However, currently many of these models are tied to assumptions of ITER-like technology and therefore tend to lead to ITER-like plant solutions.This contribution describes a broader set of plant configurations being considered alongside the main baseline design, investigating the impacts on design and costs of designing for (1) flexi-pulsed-steady-state operation, (2) double-null divertors, and (3) the use of high-temperature superconductors. The focus of the work presented here, however, is on (4) advanced magnetic configurations such as snowflake and super-X divertors. We discuss the modifications necessary for the systems code to simulate these configurations and their performance, particularly the divertor geometry and power handling capability; rapid engineering analysis of TF and PF coil positions which can achieve both the required equilibrium and remote-handling access; and initial wider analysis of the physics, neutronics, and other considerations. The reductions in wall area available for breeding tritium affect the choice of blanket technology, and remote handling considerations have a strong impact on the configurations which can be considered reasonable from an engineering and availability perspective. The benefits, disadvantages, risks, and power plant relevance of each configuration over the baseline DEMO design are discussed.

DEMO Central Solenoid Design Based on the Use of HTS Sections at Highest Magnetic Field

Previous studies indicated that the use of high-temperature superconductors (HTS) in the highest field allows us achieving the required magnetic flux in the central solenoid (CS) of the European DEMO at a reduced outer diameter, which would enable a reduced overall size and cost of DEMO. The proposed winding pack design of the CS1 module is based on ten layer-wound subcoils using an HTS, react and wind Nb3Sn, and NbTi conductors in the high, medium, and low field sections, respectively. The design utilizes a stainless steel and a superconductor grading leading to different overall current densities in each of the ten subcoils. Both, the hoop stress and the vertical loads are taken into consideration for determination of the required stainless steel cross-section in the winding pack. The stainless steel grading has been found to have an even more pronounced effect on the overall subcoil current densities than the superconductor grading. A preliminary estimation of the space required for the precompression structure is also reported.

Surface Resistance of Superconductors in the Presence of a DC Magnetic Field: Frequency and Field Intensity Limits

We revisit the classical rigid-fluxon model which describes the effect of an applied magnetic flux on the RF surface resistance of a superconductor and discuss explicit formulations for a few limit cases. As an application, we discuss the role of magnetic flux on the enhanced surface resistance of RF accelerating cavities based on niobium, depending on its material properties. We also assess the conditions for the use of high-temperature superconductors for carrying the beam image RF currents in future high-energy circular hadron colliders such as the future circular collider being studied at CERN.

Development of REBCO-Based Magnets for Plasma Physics Research

The accessible performance range for most magnetic confinement plasma physics devices expands markedly with increasing magnetic flux density. The MIT Plasma Science and Fusion Center is investigating the use of high-temperature superconductors as a low cost means to significantly enhance the performance characteristics of small to moderate scale devices. Our initial investigation emphasized the no-insulation winding technique as a means to produce highly stable dc magnets for devices operating at moderate to high magnetic flux density. We present design, manufacture, and test results for a double pancake coil wound from a 500 m length of 12 mm wide REBCO tape. The coil provides on-axis magnetic flux density within an 8 cm clear bore in excess of 0.5 T when operated in liquid nitrogen and in excess of 6 T when operated in liquid helium. The ultimate aim of the program is to develop conduction-cooled HTS coil modules that can be used for both linear and toroidal plasma devices.