A Numerical Study of Quench in the NHMFL 32 T Magnet

Cavallucci, Lorenzo; Breschi, Marco; Ribani, Pier Luigi; Gavrilin, A.V.; Weijers, H.W.; Noyes, P. D.

doi:10.1109/tasc.2019.2900175

Cited by 29 publications

(13 citation statements)

References 9 publications

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“…Knowledge of J c (B, θ) for each conductor at varying temperatures is required for accurate quench modeling, but the large number of conductors and their generally short lengths makes generation of J c (B, θ, T) for each conductor length an unrealistic and time-consuming task. To start to assess the true nature of this challenge, this paper was designed to explore J c (B, T) for 4 tapes across the significant range of properties obtained in the 32 T procurement for which an extensive quench model was developed [16][17][18], originally on the basis of extended measurements on just one tape [9].…”

Section: Introductionmentioning

confidence: 99%

Development of general expressions for the temperature and magnetic field dependence of the critical current density in coated conductors with variable properties

Francis

Abraimov

Viouchkov

et al. 2020

Supercond. Sci. Technol.

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REBa 2 Cu 3 O y coated conductors have recently become viable for high field superconducting magnets and this use may be the principal present driver of coated conductor development. Driving the transport critical current density (J c ) as high as possible has become one of the principal goals of CC manufacturers but this can only be done by developing highly engineered nanostructures that may not be easy to control in quantity production of long lengths. Protection of high field (B) magnets operating in the temperature (T) of 4-20 K range is challenging and one key data set needed for accurate quench modeling is a wide-ranging J c (B, T) data set. At the National High Magnetic Field Laboratory (NHMFL), 12 km of REBCO tapes were purchased for the allsuperconducting 32 T user magnet that successfully reached field recently. They were characterized at 4.2 K with field orientation B perpendicular to tape and at 18°off the tape-plane axis. Of the tapes selected for 32 T, three were chosen for additional J c (B, T) characterization from 4.2 to 75 K in the B^tape orientation in fields from 1 to 15 T. Although all tape lengths were bought to the same advanced pinning specification, in fact there was substantial variation of more than 2 in the low temperature, high field J c . Here we probe the reasons for this variability in the context of measurements of the transport J c (B, T) dependence of 3 representative samples from this distribution with Ginzburg-Landau models of vortex pinning using a power law for J c (B) and an exponential temperature dependence for T<45 K and 3 T<B<15 T. A fourth tape from the 32 T magnet procurement with J c outside this range was then selected to test the validity of our modelling. Using this extensive data set, the correlation between J c (B, 4.2 K) and J c (B, T) enabled us to predict J c (B, T) for tapes procured for the 32 T magnet with an expected accuracy of 10% or less for T<40 K and B up to 15 T. Transmission electron microscopy made clear that the BaZrO 3 (BZO) size, volume fraction and density varied significantly across the range of conductors studied, suggesting that nano-structural control is difficult during coated conductor manufacture and that the resulting J c variations may have to be accepted in procurement practice.

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Section: Introductionmentioning

confidence: 99%

Development of general expressions for the temperature and magnetic field dependence of the critical current density in coated conductors with variable properties

Francis

Abraimov

Viouchkov

et al. 2020

Supercond. Sci. Technol.

View full text Add to dashboard Cite

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“…When dealing with lager systems the speed up factors of the T-A homogenous models can be increased. For instance, the 32 T all-superconducting magnet from the NHMFL in Tallahassee has an HTS insert made of more than 20000 turns of REBCO tape [54]- [56], and there is not a published full model for such system. It is reported in [57], that the T-A homogenous model of the 32 T magnet [58] is 396.2 times faster than the H iterative multi-scale model of the same magnet [59].…”

Section: Comparisonmentioning

confidence: 99%

Advanced electromagnetic modeling of large-scale high-temperature superconductor systems based on H and T-A formulations

Berrospe-Juarez

Trillaud

Zermeño³

et al. 2021

Supercond. Sci. Technol.

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The development of the high-temperature superconductors (HTS) has allowed the emergence of diverse superconductor devices. Some of these devices, like wind power generators and high-field magnets, are classified as large-scale HTS systems, because they are made of several hundreds or thousands of turns of conductors. The electromagnetic analysis of such systems cannot be addressed by means of the available analytical models. The finite-element method has been extensively used to solve the H formulation of the Maxwell's equations, thus far with great success. Nevertheless, its application to large scale HTS systems is still hindered by excessive computational load. The recently proposed T-A formulation has allowed building more efficient models for systems made of HTS tapes. Both formulations have been successfully applied in conjunction with the homogenization and multi-scaling methods, these advanced methods allow reducing the required computational resources. A new advanced method, called densification, is proposed here. The most important contribution of this article is the comprehensive comparison of the strategies emerged from the combined use of the two formulations and the three advanced methods.

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“…The challenge here might be development of the end mirror coils with highest accessible magnetic field to reduce the plasma loss rate out the ends. Relying upon the latest advancements in superconductors technology, which are already being used to build magnets with fields as strong as 32 T [37], we consider it possible to design all-superconducting 25 T or higher field mirror coils for the final stage of the project in ALIANCE-III device [38]. A separate problem is the neutron shielding of the mirror coils, which must be capable to prevent fast degradation of superconducting materials to ensure continuous operation.…”

Section: Superconducting Magnetsmentioning

confidence: 99%

Development strategy for steady-state fusion volumetric neutron source based on the gas-dynamic trap

et al. 2020

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The paper presents the project and the development strategy of a continuously operating high-flux (>) fusion volumetric neutron source. The proposed facility is based on the gas-dynamic magnetic plasma confinement device with high-power () neutral beam injection. Project roadmap includes construction of several prototype installations addressing a specific set of physics and engineering problems, starting from the continuous operation of critical subsystems and ending with advanced plasma physics problems specific to axisymmetric mirror-based plasma confinement machines. The project aims to build the widest possible international collaboration to create a multi-purpose experimental facility, which could solve a set of problems most critical to deployment of economical fusion power worldwide. The paper details on the core principles of operation of a gas-dynamic neutron source, presents the parameters, expected performance and basic construction principles of intermediate and final devices, and outlines the ways to resolve the scientific and engineering challenges that constitute the project.

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A Numerical Study of Quench in the NHMFL 32 T Magnet

Cited by 29 publications

References 9 publications

Development of general expressions for the temperature and magnetic field dependence of the critical current density in coated conductors with variable properties

Development of general expressions for the temperature and magnetic field dependence of the critical current density in coated conductors with variable properties

Advanced electromagnetic modeling of large-scale high-temperature superconductor systems based on H and T-A formulations

Development strategy for steady-state fusion volumetric neutron source based on the gas-dynamic trap

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