TY - JOUR
T1 - Study on the performance improvement of the high temperature superconducting coil with several separated coils at the edges
AU - Ishiguri, S.
AU - Oka, T.
AU - Fukui, S.
AU - Ogawa, J.
AU - Sato, T.
PY - 2008/9/15
Y1 - 2008/9/15
N2 - In designing high temperature superconducting (HTS) coils, it is important to secure large magnetic fields and stored energy using shorter tape length. Thus, it is necessary to improve the transport current performance of the coils. The critical current and n-value of an HTS tape depend on magnetic fields and flux angles under constant temperature. Considering these dependencies, we established a model to analyze coil critical current. This model clarifies that relatively large electric fields are generated at the coil edges. This adversely affects the transport current performance. In this study, the coil edge is separated into several coils, keeping the total tape length constant. This increases the coil critical current, stored energy, central magnetic field, and also the coil volume, which contains vacancies created by the separation. To estimate coil performance, we calculated the stored energy density, whose denominator is the increased coil volume. This stored energy density reaches its maximum value when the number of the separated coils is eight. At this optimum separation, the central magnetic field increases by 13%, and the stored energy improves by 43%, compared to a rectangular coil wound with the same tape length.
AB - In designing high temperature superconducting (HTS) coils, it is important to secure large magnetic fields and stored energy using shorter tape length. Thus, it is necessary to improve the transport current performance of the coils. The critical current and n-value of an HTS tape depend on magnetic fields and flux angles under constant temperature. Considering these dependencies, we established a model to analyze coil critical current. This model clarifies that relatively large electric fields are generated at the coil edges. This adversely affects the transport current performance. In this study, the coil edge is separated into several coils, keeping the total tape length constant. This increases the coil critical current, stored energy, central magnetic field, and also the coil volume, which contains vacancies created by the separation. To estimate coil performance, we calculated the stored energy density, whose denominator is the increased coil volume. This stored energy density reaches its maximum value when the number of the separated coils is eight. At this optimum separation, the central magnetic field increases by 13%, and the stored energy improves by 43%, compared to a rectangular coil wound with the same tape length.
KW - Central magnetic field
KW - Critical current
KW - HTS coil
KW - Stored energy
UR - http://www.scopus.com/inward/record.url?scp=50349088575&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=50349088575&partnerID=8YFLogxK
U2 - 10.1016/j.physc.2008.05.206
DO - 10.1016/j.physc.2008.05.206
M3 - Article
AN - SCOPUS:50349088575
VL - 468
SP - 2152
EP - 2155
JO - Physica C: Superconductivity and its Applications
JF - Physica C: Superconductivity and its Applications
SN - 0921-4534
IS - 15-20
ER -