Current Capacity of Cu-Sheathed Multifilamentary Coated Conductors under the Influence of Spatial Variation of Local Critical Currents in Each Filament

Kohei Higashikawa, Takumi Suzuki, Masayoshi Inoue, Shinji Fujita, Yasuhiro Iijima, Takanobu Kiss

Research output: Contribution to journalArticle

Abstract

We investigated the relationship between current capacity and local critical current distribution of a Cu-sheathed multifilamentary RE-123 coated conductor (CC). Patterning multifilamentary structure on CC will be a promising solution for reducing magnetization to assure spatial homogeneity and its temporal stability of magnet applications such as MRI and NMR. On the other hand, it will become more difficult to maintain the current capacity because a smaller defect can block the current flow in a narrower filament. Permitting electrical coupling among the filaments will work for maintaining current capacity because current can avoid such a defect by flowing into the adjacent filament. However, too small interfilamentary resistance will result in long time constant of filament coupling, which will affect spatial homogeneity and its temporal stability of magnet applications. Therefore, to design a multifilamentary CC satisfying the requirement from magnet applications, it is necessary to understand the quantitative impact of interfilamentary resistance of the multifilamentary CC on its current capacity under the influence of spatial variation of local critical currents. In this study, we estimated global critical current of a Cu-sheathed multifilamentary CC as a function of interfilamentary resistance by considering its local critical current distribution in each filament. As a result, it was confirmed that the electrical coupling among the filaments was very effective to improve the current capacity of such a multifilamentary CC especially for a section with spatially inhomogeneous local critical currents. Furthermore, it was also found that local heat generation could be significantly suppressed even for a section with relatively homogeneous local critical currents.

Original languageEnglish
Article number8263216
JournalIEEE Transactions on Applied Superconductivity
Volume28
Issue number3
DOIs
Publication statusPublished - Apr 1 2018

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Critical currents
critical current
filaments
conductors
Magnets
magnets
current distribution
homogeneity
Defects
Heat generation
heat generation
defects
Magnetic resonance imaging
Magnetization
time constant
Nuclear magnetic resonance
magnetization
requirements
nuclear magnetic resonance

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

Cite this

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title = "Current Capacity of Cu-Sheathed Multifilamentary Coated Conductors under the Influence of Spatial Variation of Local Critical Currents in Each Filament",
abstract = "We investigated the relationship between current capacity and local critical current distribution of a Cu-sheathed multifilamentary RE-123 coated conductor (CC). Patterning multifilamentary structure on CC will be a promising solution for reducing magnetization to assure spatial homogeneity and its temporal stability of magnet applications such as MRI and NMR. On the other hand, it will become more difficult to maintain the current capacity because a smaller defect can block the current flow in a narrower filament. Permitting electrical coupling among the filaments will work for maintaining current capacity because current can avoid such a defect by flowing into the adjacent filament. However, too small interfilamentary resistance will result in long time constant of filament coupling, which will affect spatial homogeneity and its temporal stability of magnet applications. Therefore, to design a multifilamentary CC satisfying the requirement from magnet applications, it is necessary to understand the quantitative impact of interfilamentary resistance of the multifilamentary CC on its current capacity under the influence of spatial variation of local critical currents. In this study, we estimated global critical current of a Cu-sheathed multifilamentary CC as a function of interfilamentary resistance by considering its local critical current distribution in each filament. As a result, it was confirmed that the electrical coupling among the filaments was very effective to improve the current capacity of such a multifilamentary CC especially for a section with spatially inhomogeneous local critical currents. Furthermore, it was also found that local heat generation could be significantly suppressed even for a section with relatively homogeneous local critical currents.",
author = "Kohei Higashikawa and Takumi Suzuki and Masayoshi Inoue and Shinji Fujita and Yasuhiro Iijima and Takanobu Kiss",
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AU - Suzuki, Takumi

AU - Inoue, Masayoshi

AU - Fujita, Shinji

AU - Iijima, Yasuhiro

AU - Kiss, Takanobu

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