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

Change log

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, Jc, 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 Jc 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.

superconducting stacks, cross-field demagnetization, modeling of high temperature superconductors, 3D modeling, ReBCO coated conductors, supermagnets, rotating machines
Journal Title
Superconductor Science and Technology
Conference Name
Journal ISSN
Volume Title
IOP Publishing
All rights reserved
Engineering and Physical Sciences Research Council (EP/P000738/1)
European Commission Horizon 2020 (H2020) Societal Challenges (723119)
European Union's Horizon 2020 research innovation program under grant agreement No 7231119 (ASuMED consortium).