Modelling and mitigating flux jumps in bulk high-temperature superconductors during quasi-static, high-field magnetisation

TY - JOUR

T1 - Modelling and mitigating flux jumps in bulk high-temperature superconductors during quasi-static, high-field magnetisation

AU - Cientanni, Vito

AU - Ainslie, Mark D.

N1 - Funding Information: Vito Cientanni would like to acknowledge financial support from the EPSRC DTP Fund. Some of the work of M D Ainslie was carried out while affiliated with the Bulk Superconductivity Group, Department of Engineering, University of Cambridge, and supported in part by an EPSRC Early Career Fellowship, EP/P020313/1. Publisher Copyright: © 2023 The Author(s). Published by IOP Publishing Ltd.

PY - 2023/1/10

Y1 - 2023/1/10

N2 - (RE)-Ba 2Cu 3O 7 − δ bulk superconductors acting as permanent trapped field magnet analogues have been shown to trap fields in excess of 17 T. However, the occurrence of thermomagnetic instabilities during their magnetisation process can limit their performance. In 2019, Naito et al trapped 15.1 T in a (Y)-BaCuO bulk pair under applied fields of up to 22 T (2019 J. Appl. Phys. 126 243901), whilst also documenting the mechanical failure of the bulks due to a flux jump. Here, we accurately numerically model this experiment and the observed flux jump, providing insight into the experimental results, such as the role of heating, the presence of thermal gradients, and a possible reason for the location of the bulk-pair fracturing. Extending the study with an investigation into the role of enhanced cooling of the bulk-pair, the influence of cooling power on the calculated trapped field and flux jump is explored. Finally, we propose and numerically investigate a new composite bulk configuration, consisting of stacks of (Y)-BaCuO bulk and interspaced metallic discs, to enhance the thermal stability of the bulk pair, to ultimately improve the trapped field performance.

AB - (RE)-Ba 2Cu 3O 7 − δ bulk superconductors acting as permanent trapped field magnet analogues have been shown to trap fields in excess of 17 T. However, the occurrence of thermomagnetic instabilities during their magnetisation process can limit their performance. In 2019, Naito et al trapped 15.1 T in a (Y)-BaCuO bulk pair under applied fields of up to 22 T (2019 J. Appl. Phys. 126 243901), whilst also documenting the mechanical failure of the bulks due to a flux jump. Here, we accurately numerically model this experiment and the observed flux jump, providing insight into the experimental results, such as the role of heating, the presence of thermal gradients, and a possible reason for the location of the bulk-pair fracturing. Extending the study with an investigation into the role of enhanced cooling of the bulk-pair, the influence of cooling power on the calculated trapped field and flux jump is explored. Finally, we propose and numerically investigate a new composite bulk configuration, consisting of stacks of (Y)-BaCuO bulk and interspaced metallic discs, to enhance the thermal stability of the bulk pair, to ultimately improve the trapped field performance.

KW - Bulk high-temperature superconductors

KW - flux jumps

KW - field-cooled magnetisation

KW - trapped field

KW - numerical modelling

KW - finite element method

KW - composite structures

UR - https://doi.org/10.18742/21215801

UR - http://www.scopus.com/inward/record.url?scp=85146493006&partnerID=8YFLogxK

U2 - 10.1088/1361-6668/acaa06

DO - 10.1088/1361-6668/acaa06

M3 - Article

SN - 0953-2048

VL - 36

JO - Superconductor Science and Technology

JF - Superconductor Science and Technology

IS - 2

M1 - 025007

ER -