Numerical simulation of critical current degradation of Nb3Sn strand in CIC conductor

Haruyuki Murakami, Atsushi Ishiyama, Hiroshi Ueda, Norikiyo Koizumi, Kiyoshi Okuno

Research output: Contribution to journalArticlepeer-review


The critical current of the ITER model coil degraded with an increase in the electromagnetic force. Experiments in which a periodic transverse load was artificially applied to a single coil strand showed this degradation. However, since these experiments were carried out under a certain condition, a general relation between the transverse load and the critical current was not obtained. Therefore, we have developed a numerical simulation code to investigate this general relation. The results of the numerical simulations are in good agreement with the experiments. This indicates that our numerical code is valid for the evaluation of the critical current performance of strands in CIC conductor. Next, the general dependence of the critical current degradation on Ta barrier thickness and resistivity of bronze was evaluated by using the developed simulation code. The results of the calculation showed that the Ta barrier thickness affects the critical current characteristics because of the large flexural rigidity of Ta barrier. On the other hand, the resistivity of bronze and the twist pitch of the filament rarely affect the critical current degradation since current transfers between filaments do not occur within the practical resistivity range of bronze.

Original languageEnglish
Article number4510705
Pages (from-to)1051-1054
Number of pages4
JournalIEEE Transactions on Applied Superconductivity
Issue number2
Publication statusPublished - Jun 2008
Externally publishedYes


  • Bending strain
  • CICC
  • Critical current
  • Degradation
  • NbSn strand
  • Numerical simulation

ASJC Scopus subject areas

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


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