AC losses in multifilamentary Nb&amp;lt;inf&amp;gt;3&amp;lt;/inf&amp;gt;Sn conductors

Charlesworth, J. P.; Sikora, P. T.

doi:10.1109/tmag.1979.1060152

Cited by 7 publications

(1 citation statement)

References 12 publications

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“…Hysteresis losses well below 0.1 W m-2 at 50 Hz (2 x J m-2 per cycle) at 6.5 K for surface currents of 40 RMSA mm-' have been measured in a prototype flexible core for a 2 GVA cable (Lewis et a1 1978) in which the core was constructed of spiralled strips of a Nb/Nb-Zr/Cu composite. Nb on A1 has also been shown to provide a successful cable core (Bogner et a1 1977), although other candidates with losses almost as low are Nb$n clad with stainless steel and copper in the form of tape (Garber 1979) and multifilamentary Nb3Sn (Charlesworth andSikora 1979, Sumiyoshi et a1 1978). In Nb3Sn a coarse structured surface layer was recognised as one of the factors contributing to undesirable AC loss (Brisbin eta1 1977(Brisbin eta1 ,1979, and for rather different reasons surface roughness is one of the principal causes of loss in Nb at Meissner surface current densities less than H,,.…”

Section: Introductionmentioning

confidence: 99%

Dependence of AC loss in superconducting niobium above and below H_c1on surface and bulk condition

Sobieradzki

Doidge

1982

J. Phys. D: Appl. Phys.

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Waveforms of rates of change of flux have been recorded over a wide range of fields above and below Hc1 in superconducting niobium strips with a variety of degrees of surface roughness. The waveforms are compared with those predicted by Melville's theory (1971-2) that attributes AC loss below Hc1 to pinning within the peaks, and derived losses are also compared. Although the predicted double maxima of the waveforms per half cycle are observed at most fields, their development near Hc1 is more gradual than expected, and at fields well below Hc1 single maxima are observed that appear to be associated with discrete protuberances. It is confirmed that dissolved oxygen is liable to be a more serious practical cause of high loss than moderate roughness.

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Section: Introductionmentioning

confidence: 99%