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Cross-field demagnetization of stacks of tapes: 3D modeling and measurements

Authors :
Enric Pardo
Algirdas Baskys
Francesco Grilli
Bartek A. Glowacki
Anang Dadhich
Vicente Climente-Alarcon
Milan Kapolka
Kapolka, M [0000-0002-4932-2946]
Pardo, E [0000-0002-6375-4227]
Grilli, F [0000-0003-0108-7235]
Glowacki, BA [0000-0003-2165-6378]
Apollo - University of Cambridge Repository
Baskys, A [0000-0002-1875-8107]
Climente-Alarcon, V [0000-0002-1273-8454]
Glowacki, B A [0000-0003-2165-6378]
Source :
Superconductor science and technology, 33 (4), Art. Nr.: 044019, Superconductor Science and Technology
Publication Year :
2020
Publisher :
Apollo - University of Cambridge Repository, 2020.

Abstract

Stacks of superconducting tapes can trap much higher magnetic fields than conventional magnets. This makes them very promising for motors and generators. However, ripple magnetic fields in these machines present a cross-field component that demagnetizes the stacks. At present, there is no quantitative agreement between measurements and modeling of cross-field demagnetization, mainly due to the need of a 3D model that takes the end effects and real micron-thick superconducting layer into account. This article presents 3D modeling and measurements of cross-field demagnetization in stacks of up to 5 tapes and initial magnetization modeling of stacks of up to 15 tapes. 3D modeling of the cross-field demagnetization explicitly shows that the critical current density, $J_c$, in the direction perpendicular to the tape surface does not play a role in cross-field demagnetization. When taking the measured anisotropic magnetic field dependence of $J_c$ into account, 3D calculations agree with measurements with less than 4 % deviation, while the error of 2D modeling is much higher. Then, our 3D numerical methods can realistically predict cross-field demagnetization. Due to the force-free configuration of part of the current density, J, in the stack, better agreement with experiments will probably require measuring the Jc anisotropy for the whole solid angle range, including $J$ parallel to the magnetic field.<br />Comment: 36 pages, 20 figures

Details

ISSN :
09532048 and 13616668
Database :
OpenAIRE
Journal :
Superconductor science and technology, 33 (4), Art. Nr.: 044019, Superconductor Science and Technology
Accession number :
edsair.doi.dedup.....2235fdb0ca54e5ffc295db7581773774
Full Text :
https://doi.org/10.17863/cam.50474