Screening of Eddy Current Loss in Metal Layers of Coated HTS Conductors

Numerical Computation of AC Losses and Flux Profiles in High-Aspect-Ratio Superconducting Strips in Perpendicular AC Magnetic Field

“…7(a) and (b) and lower ac loss. We have also demonstrated the screening effects in copper eddy-current loss by the superconductor at low magnetic fields [28]. Comparing Fig.…”

“…The other details of our experimental system were presented in the literature [2], [28], [29]. The sample length was 150 mm.…”

“…The external field was applied perpendicular to the wide face of the conductor. The results obtained from the use of this measurement gear have been presented in the literature [2], [28], [29].…”

“…Several numerical [3]- [13] and analytical techniques [14]- [18] have been developed. Remarkable progress has been made in understanding the behavior of superconductors deposited on a weakly ferromagnetic substrate [2], [15], [20]- [27] and the screening effects of the copper-stabilizer layer [28]. The pioneering work of Brandt and Indenbom [14] has been successful in calculating the ac loss in superconducting strips deposited on a nonmagnetic substrate.…”

Hysteretic ac loss in a coated superconductor subjected to oscillating magnetic fields: ferromagnetic effect and frequency dependence

“…The dependence of the total loss in the entire coated superconductor, illustrated in the right figure, indicates that, the hysteretic ac loss in the superconducting layer is dominant at the small values of μ 0 H a , where an exponential decrease of the total loss with the frequency is displayed, whereas at the large values of μ 0 H a , a quasilinear increase in the hysteretic ac loss emerges, implying that the contribution of the eddy-current loss in the metal coatings becomes prominent. Figure 5 shows the dependence of the normalized hysteretic ac loss U ac /(μ 0 H a ) 2 in the respective metal coating on the amplitude of an applied transverse magnetic field μ 0 H a to demonstrate how the screening effect [40] due to the induced supercurrent in the superconducting layer affects these dependences at different frequencies. It can be seen from this figure that, given any value of the frequency, the screening effect mostly acts at small and moderate values of μ 0 H a , particularly towards the silver for which a roughly linear increase is found, whereas at large values of μ 0 H a , the normalized hysteretic ac loss nearly keeps constant as it should [38], implying an insignificant screening effect.…”