Magnetization and design of multistrand superconducting conductors

Walters, C.R.

doi:10.1109/tmag.1975.1058684

Cited by 15 publications

(5 citation statements)

References 2 publications

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“…We model the quench state-transition through a suitable transition-variable ξ ht . Joule losses are accounted as Q Ohm = J s · σ −1 ht J s , where the equivalent half-turn resistivity σ −1 ht is calculated using a reformulation of the Stekly approximation [17] for the current sharing regime [18], simplifying the extraction of the coil's equivalent resistance(Sec. II-D).…”

Section: Heat Balancementioning

confidence: 99%

A 2-D Finite-Element Model for Electrothermal Transients in Accelerator Magnets

et al. 2018

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Superconducting accelerator magnets require sophisticated monitoring and means of protection due to the large energy stored in the magnetic field. Numerical simulations play a crucial role in understanding transient phenomena occurring within the magnet, and can, therefore, help to prevent disruptive consequences. We present a 2-D FEM model for the simulation of electro-thermal transients occurring in superconducting accelerator magnets. The magnetoquasistatic problem is solved with a modified magnetic vector potential formulation, where the cable eddy currents are resolved in terms of their equivalent magnetization. The heat balance equation is then investigated, and the relevant heat sources are discussed. The model implements a two-port component interface and is resolved, as part of an electrical circuit, in a cooperative simulation scheme with a lumped-parameter network.

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Section: Heat Balancementioning

confidence: 99%

A 2-D Finite-Element Model for Electrothermal Transients in Accelerator Magnets

et al. 2018

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“…According to [6] the concept of n-index was first introduced by Walters [7]. In an early work [8] Voelker observed that the logarithmic slope of the VAC slowly varies with field and current for a given sample of wire while it can be very different from sample to sample, due to broken filaments, twisting, metallurgical treatment, copper-to-superconductor bond or some other features.…”

Section: Empirical Modelsmentioning

confidence: 99%

Critical current statistical distribution and voltage–current characteristics in superconducting wires

Manfreda

Bellina

Volpini

2014

Supercond. Sci. Technol.

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Type II superconductors, like Nb-Ti and Nb 3 Sn, play a central role in the design of magnets for fusion and particle accelerators. These materials show experimentally a longitudinal electric field which depends in a nonlinear way on the current. Different models have been developed to analyse this phenomenon, mainly based on the role of defects and inhomogeneities in the superconducting sample. Some of these models are based on a statistical description of the critical current distribution along the wire, that can explain the presence of a curvature in the volt-ampere characteristic (VAC). In the work we have studied the impact of different critical current statistical distributions on the VAC and their implications, and compared some experimental data with our theoretical results.

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“…* According to his tests, the braid was much more susceptible to induced magnetization currents than the Brookhaven scientists thought. 46 While this drew the concern of Hahn and one or two other insiders, the concern did not propagate.…”

Section: Phys Perspect 358mentioning

confidence: 99%

Quenched! The ISABELLE Saga, I

Crease

2005

Phys. perspect.

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The story of ISABELLE, a colliding-beam accelerator conceived in 1971, officially approved in 1978, partially constructed, and terminated in 1983, is an important episode in the history of postWorld War II science in the United States. The events surrounding its planning, construction, and termination reveal much about the ambitions, strategies, and tensions of American high-energy physicists, their collaborations and rivalries, and the difficulties of funding and constructing a large scientific facility in the age of Big Science. In this article, the first of two parts, I cover the period up to the beginning of construction in 1978. I place ISABELLE in the context of the early history of colliders, outline the physics goals that motivated the machine, and describe the research and motivations behind its innovative but ultimately problematic superconducting magnet design. I cover the key technological and administrative steps that the laboratory took to get the project underway and steer it past several review committees. I also treat some of the conflicts within the laboratory, and between Brookhaven and other laboratories, especially Fermilab, that hampered the project.The story of ISABELLE, a colliding-beam accelerator conceived in 1971, officially approved in 1978, partially constructed, and terminated in 1983, is an important episode in the history of post-World War II science in the United States. The events surrounding its planning, construction, and termination reveal much about the ambitions, strategies, and tensions of American high-energy physicists, their collaborations and rivalries, and the difficulties of funding and constructing a large scientific facility in the age of Big Science. What makes the traumatic story of ISABELLE an especially good portal into the thinking and sociology of physicists of the day is that it seemed the most natural of next steps by a forefront accelerator laboratory to advance the interests of the high-energy physics community.From the moment the United States National Laboratory system was established, it was clear that the two laboratories focusing on elementary-particle physicsBrookhaven and Berkeley -had to build ever larger accelerators to stay vital. This

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Magnetization and design of multistrand superconducting conductors

Cited by 15 publications

References 2 publications

A 2-D Finite-Element Model for Electrothermal Transients in Accelerator Magnets

A 2-D Finite-Element Model for Electrothermal Transients in Accelerator Magnets

Critical current statistical distribution and voltage–current characteristics in superconducting wires

Quenched! The ISABELLE Saga, I

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