Magnetization of YBCO film with ac travelling magnetic waves of relatively short wavelengths

Abstract

The magnetizations of the YBCO film with ac travelling magnetic waves of relatively short wavelengths were studied. The results have verified that the reported “intermediate value” of the superconducting current density [Wang et al., Appl. Phys. Lett. 104(3), 032602 (2014)] was caused by the existence of multiple transition regions in the sample: the magnetic poles induce ±JC in the pole regions, which produces two transition regions within each wavelength λ (+JC→−JC→+JC, and vice versa, while the symbol → indicates the transition region). The current densities in the transition region are with intermediate values, which are smaller than the critical value. In case of relatively short wavelength, there are multiple transition regions, which occupy a large fraction of the YBCO sample with intermediate current values. Moreover, the wavelike current distributions might help explain the flux transportation and dc output voltage in HTS flux pump.

Modeling methodology for the transformer-rectifier flux pump considering electromagnetic and thermal coupling

“…It can reduce the cost of high-performance DC power supplies, improve the stability of operating current through timely injecting DC current into HTS magnets wirelessly. The existing HTS flux pumps can be mainly divided into two categories, namely, the travelling wave flux pump [15][16][17][18][19][20][21][22][23][24][25] and transformer-rectifier flux pump [26][27][28][29]. The transformerrectifier flux pump relies on the rectifying circuit and switching effect of HTS wire [30].…”