Evaluation of electromagnetic behavior of no-insulation rebco pancake coil with multiple defects

Yuta Kakimoto, Tetsuri Ichikawa, Haruka Onoshita, Tetsuro Kinpara, Atsushi Ishiyama, So Noguchi

Research output: Contribution to journalArticle

Abstract

We previously developed a high-magnetic-field REBCO coil for use in medical devices such as medical accelerators and high-magnetic-field MRI. The use of high-temperature superconducting (HTS) coils in such applications necessitates their miniaturization while providing high magnetic fields. However, when the current density is improved by reducing the copper-stabilization-layer thickness in the conventional insulated HTS coil, the thermal stability is lowered, which leads to a tradeoff between high current density and high thermal stability. Therefore, we examine no-insulation (NI) coils that allow compatibility between high current density and thermal stability. Recent research has indicated that NI coils with multiple defects can afford a stable and high critical current (Ic) and operate without serious problems, which makes it possible to produce coils wound with commercial REBCO tapes containing several defects along the tape, which in turn makes fabrication economically viable. However, there are many unknown aspects of the current, magnetic field, and heat behaviors of NI coils with defects, particularly when large currents flow through them. Here, in order to examine the behavior of a multiple-defect NI coil subjected to a large current at the temperature of ∼30 K via application of the conduction cooling method, we use a combination of the partial element equivalent circuit method and the finite-element method to investigate the detailed current and thermal behaviors. Our results indicate that defective NI coils can afford a critical current Ic value of ∼80% of that of defect-free NI coils, which makes our findings valuable in terms of contributing to further developments in HTS coil applications.

Original languageEnglish
Article number8664091
JournalIEEE Transactions on Applied Superconductivity
Volume29
Issue number5
DOIs
Publication statusPublished - 2019 Aug 1

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insulation
Insulation
coils
electromagnetism
Defects
evaluation
defects
Magnetic fields
Thermodynamic stability
Current density
Critical currents
Tapes
thermal stability
Temperature
current density
magnetic fields
tapes
high current
critical current
Equivalent circuits

Keywords

  • Conduction cooling
  • high-temperature superconducting coil
  • ic defect
  • no-insulation coil
  • PEEC model

ASJC Scopus subject areas

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

Cite this

Evaluation of electromagnetic behavior of no-insulation rebco pancake coil with multiple defects. / Kakimoto, Yuta; Ichikawa, Tetsuri; Onoshita, Haruka; Kinpara, Tetsuro; Ishiyama, Atsushi; Noguchi, So.

In: IEEE Transactions on Applied Superconductivity, Vol. 29, No. 5, 8664091, 01.08.2019.

Research output: Contribution to journalArticle

Kakimoto, Yuta ; Ichikawa, Tetsuri ; Onoshita, Haruka ; Kinpara, Tetsuro ; Ishiyama, Atsushi ; Noguchi, So. / Evaluation of electromagnetic behavior of no-insulation rebco pancake coil with multiple defects. In: IEEE Transactions on Applied Superconductivity. 2019 ; Vol. 29, No. 5.
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