Influence of an applied magnetic field on shielding current paths in a high TC superconductor
✍ Scribed by N. Takeda; M. Uesaka; K. Miya
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 714 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0011-2275
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✦ Synopsis
The influence of an applied magnetic field on shielding current paths in a bulk high T, superconductor was investigated. This issue is very important for the quantitative analysis of levitation force, since the distortion and localization of the current paths have been found to be a major source of discrepancy between computed and experimental results. Furthermore, it has been speculated that the current paths vary, depending on the applied magnetic field. The magnetic field due to superconducting currents was measured by a Hall sensor when a permanent magnet was positioned at different gaps from a superconductor.
The current paths were then reconstructed from the measured field data by an inverse analysis. A genetic algorithm, which is a robust probabilistic optimizing method, was used for the inverse analysis. It was found that the current paths merged into larger loops as the permanent magnet was retreating from the superconductor.
It implies that a stronger applied magnetic field locally degrades the current density (J,) and the shielding current paths are localized by these low-J, areas which act as insulating boundaries.