High Temperature Superconducting (HTS) Coils for a Compact Spherical Tokamak

Melhem, Ziad; Ball, S.; Brzakalik, Robin; Chappell, Steven P.; Gryaznevich, M.; Hawksworth, D.; Jedamzik, D.; Jokinen, Antti; Kingham, David R.; Sykes, A.; Twin, Andrew

doi:10.1109/tasc.2014.2375512

Cited by 11 publications

(5 citation statements)

References 3 publications

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“…The first fully-HTS tokamak, figure 18, has been built by TE. Ltd in 2014 and demonstrated steady-state magnet and plasma operations [14]. This full-HTS tokamak, HTS-ST, achieved 0.1 T @ R = 0.25 m for the plasma pulse duration of 29 h.…”

Section: Development Of the Hts Technologiesmentioning

confidence: 97%

“…The spherical tokamak (ST) path to fusion has been proposed in Stambaugh et al [1], and experiments on STs have already demonstrated the feasibility of this approach. Advances in high temperature superconductor (HTS) technology [13][14][15] allows significant increase in the toroidal field (TF) which was found to improve confinement in STs. The combination of the high β, which has been achieved in STs [17] and high TF that can be produced by HTS TF magnets, opens a path to lower-volume fusion reactors, in accordance with the fusion power scaling proportional to β 2 B t 4 V. The high field spherical tokamak ST40, figures 1 and 2, is a prototype on this path and is now operating.…”

Section: Introductionmentioning

confidence: 99%

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Experiments on ST40 at high magnetic field

Gryaznevich

2021

Nucl. Fusion

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The combination of the high beta values, which have been achieved in spherical tokamaks, and high toroidal field (TF) that can be produced by high temperature superconductor (HTS) TF magnets, opens a path to lower-volume fusion reactors, in accordance with the fusion power scaling ∼β t 2 B t 4 V. High field spherical tokamak ST40 is the first prototype on this path and is now operating and results of first experiments are presented. Increase in T e, T i and the thermal energy with the TF has been observed for TF up to ∼2 T in OH operations with a sharper increase at TF above 1 T, which suggests transition to a better confinement above this threshold. First results of experiments with the neutral beam injection show expected increase in the T i, plasma density and the thermal energy. Results of the merging-compression plasma formation (m/c) studies show agreement with the previous studies, however at the high TF, formation of run-away electrons has been observed for the first time during m/c start-up. Advances in the HTS development are also presented.

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Section: Development Of the Hts Technologiesmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Experiments on ST40 at high magnetic field

Gryaznevich

2021

Nucl. Fusion

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“…Reproduced with permission from [58]. (i) A Spherical Tokamak Fusion reactor under development at Tokamak Energy [59][60][61] (REBCO). Reproduced with permission from [61].…”

Section: Operating Above T = 42 K Provides Resiliencementioning

confidence: 99%

“…A final example of emerging commercial applications of HTS are compact fusion-reactors, under development, for example, at Commonwealth Fusion Systems in the U.S.A. [70], and at Tokamak Energy in the U.K. (figure 6(i) [59][60][61]). The promise of compact fusion-reactors as a solution for the climate crises has been attracting several 100 million US$ in government support, as well as a recently announced 1.8 billion US$ of private-investment funding for Commonwealth Fusion Systems [70].…”

Section: Examples Of Commercial Hts Applicationsmentioning

confidence: 99%

High temperature superconductors for commercial magnets

Godeke

2023

Supercond. Sci. Technol.

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The steadily increasing magnetic ﬁelds that can be generated with superconducting magnets are reaching the limits of what is achievable with low-temperature superconductors (LTS). At the same time, a reduction of fossil-fuel extraction will amplify the already limited availability of helium as a coolant for superconducting magnets in the near future. Hence, manufacturers of commercial applications that rely on superconducting magnets have become increasingly interested in exploring technologies that enable a move beyond the magnetic-ﬁeld limitations posed by LTS conductors, and/or enable higher operating temperatures to allow for cryogen-free operation. High-temperature superconductors (HTS), such as [RE]Ba2Cu3O7-δ (REBCO), Bi2Sr2CaCu2O8+x (Bi-2212), and Bi2-xPbxSr2Ca2Cu3O10-y (Bi-2223) have all matured to a certain commercial extent, and have thereby become enablers for such technologies. The emergence of various new commercial magnet-systems that utilize HTS, suggests that we are at the dawn of a wider commercial implementation. A review of which HTS properties are critical for these magnets, what is currently available, and what is missing, is therefore considered timely and appropriate in this context.

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“…Considerable efforts have been made to construct planar ReBCO coils for tokamak experiments [15][16][17], which are the most developed fusion concept. ReBCO is considered in the design of the central solenoid for the European DEMO reactor [18].…”

Section: Introductionmentioning

confidence: 99%

Winding angle optimization and testing of small-scale, non-planar, high-temperature superconducting stellarator coils

Huslage,

Kulla,

Lobsien

et al. 2024

Supercond. Sci. Technol.

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We designed and constructed two non-planar coils with high-temperature superconductors (HTS) based on shapes from the Wendelstein 7-X stellarator. Tape track orientation of the HTS was optimized to reduce the coil size as much as possible while staying within the strain limits of the Gadolinium Barium Copper Oxide (GdBCO) superconductor. This resulted in average coil radii of 0.23 m and 0.48 m at strain limits of up 0.45 % to for the coil shapes that were chosen.The coils were produced by winding the GdBCO tapes onto 3D-printed plastic frames. We confirmed the integrity of the superconducting layer after winding by spatially resolved measurement of the critical current and by energizing the coils in liquid nitrogen. Coil 1 showed a resistance of 1.75 µΩ and did not have any critical current degradation, while coil 5 had a resistance of 195 µΩ and showed only one dropout, attributable to a handling error. We measured the magnetic field of the coil with a 3-axis Hall probe system and found good agreement with predictions. This work demonstrates the manufacturing of small-scale, non-planar magnetic coils from commercially available HTS.

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High Temperature Superconducting (HTS) Coils for a Compact Spherical Tokamak

Cited by 11 publications

References 3 publications

Experiments on ST40 at high magnetic field

Experiments on ST40 at high magnetic field

High temperature superconductors for commercial magnets

Winding angle optimization and testing of small-scale, non-planar, high-temperature superconducting stellarator coils

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