• Progress in Superconductivity and Cryogenics
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• v.17 no.2
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• pp.50-53
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• 2015

The properties of High Temperature Superconducting (HTS) tapes are progressing, as HTS tapes evolve from 1st generation to 2nd generation. This paper presents design and construction of a 2nd generation HTS magnet consisting of two nested GdBCO and YBCO pancake coils. Two HTS tapes of different widths were used to wind the HTS nested magnet. Considering that a higher magnetic field is applied to the inner magnet than to the outer magnet, 12 mm GdBCO tape was used for winding the inner magnet, which consisted of four single pancake windings. Eight double pancake windings wound with 4.4 mm YBCO tapes were used for the outer magnet. The test results show that the central magnetic field of the HTS nested magnet was 920 mT. The measured critical currents of the inner and outer magnet at 77K were 80.8 A and 32.6 A, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.23-30
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• 2017

Most superconducting magnets which generate more than 20 T consist of nested magnets. A combination of LTS and HTS magnets is conventionally used, but high field magnets which use only HTS magnets have been developed recently. As HTS wires have very strong magnetic anisotropy, appropriate techniques should be used to consider this effect properly. The load line method has been conventionally used to design nested magnets for high field generation. Because this method considers only parallel and perpendicular magnetic fields, the effect of their orientation is not taken into account. In this paper, the actual orientation of the magnetic fields from 0 to 90 degrees is considered. The critical currents of the two kinds of high field nested magnets designed using the proposed method are calculated. The finite element method is used to calculate the distribution of the magnetic fields and the evolution strategy is used to find the critical current which maximizes the central magnetic field.