Journal ArticleDOI
Critical current density defined at low electric field criterion and energy margin of superconducting MgB 2 wires in wide temperature and magnetic field range
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In this paper, the authors defined the critical line as a line on which an electric field of 10−10 V m−1 is generated at a coil current density of 150 A mm−2.Abstract:
High-temperature superconductors (HTS) and MgB2 may potentially improve the usability of superconducting magnets dramatically owing to their large energy margin. When HTS and MgB2 wires are used for magnets operated in the persistent current mode, such as in magnetic resonance imaging (MRI) scanners, the electric field generated in the wires must be lower than 10−10 V m−1. In this paper, critical current density, J c, defined at an electric field criterion of 10−10 V m−1 is evaluated from a magnetisation decay measurement for state-of-the-art monofilamentary MgB2 wires. By using the obtained J c, a critical line of our multifilamentary MgB2 wire is shown on the temperature-magnetic field plane. Here, the critical line is defined as a line on which an electric field of 10−10 V m−1 is generated at a coil current density of 150 A mm−2. The area inside the critical line is demonstrated to be large enough to fulfil the requirement of 1.5 T MRI scanners operated at 10K–15K. In addition, the iso energy-margin lines are shown on the temperature-magnetic field plane and compared with those of NbTi wires. The MgB2 wire has an order of magnitude greater energy margin than the NbTi wires in most of the area inside the critical line. This suggests that the MgB2 wire is highly unlikely to be quenched due to mechanical disturbances.read more
Citations
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Journal ArticleDOI
Measurement of In-Field E-J Characteristics in Multi-Filamentary Bi-2223 Tapes at Ultra-Low Electric-Field Down to Around 10−13 V/m
Zeyu Wu,Takanobu Kiss,Shan Tian,Sohki Kishikawa,Kohei Higashikawa,Yoshinori Yanagisawa,Jun-ichi Shimoyama +6 more
TL;DR: In this paper , a method to investigate in-field electric-field v.s. characteristics at ultra-low electric field criterion around 10−13 V/m in a multi-filamentary Bi-2223 tape at 5 K based on scanning Hall probe microscopy (SHPM) was developed.
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Feasibility study of novel rapid ramp-down procedure in MgB2 MRI magnet using persistent current switch with high off-resistivity
Motomune Kodama,Hiroshi Kotaki,Shinya Ohara,Yota Ichiki,Shinji Fujita,Takaaki Suzuki,Hideki Tanaka,Aoki Manabu +7 more
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Enhanced critical current density at high magnetic fields in MgB2 wire processed by in-situ spark plasma sintering
Lili Wang,Natalie Grobshäuser,Weidong Chen,Chengshan Li,Guo Yan,Yong Feng,Pingxiang Zhang,Yong Zhang,Yong Zhao,Yong Zhao +9 more
TL;DR: In this paper, the effect of different SPS sintering conditions on the phase formation, microstructure characteristics and superconductivity of the MgB2 material are studied.
Journal ArticleDOI
Enhanced critical current density at high magnetic fields in MgB2 wire processed by in-situ spark plasma sintering
TL;DR: In this paper , the effect of different SPS sintering conditions on the phase formation, microstructure characteristics and superconductivity of the MgB2 material are studied.
Journal ArticleDOI
Relation between constituent material fraction in multifilamentary MgB2 wires and requirements for MRI magnets
TL;DR: In this article , the in situ MgB2 wires with an iron matrix and a Monel reinforced member were evaluated for magnetic resonance imaging (MRI) applications and two types of protection approaches of the magnet were considered.
References
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Journal ArticleDOI
Conductors for commercial MRI magnets beyond NbTi: requirements and challenges
TL;DR: Conductor technology is an important, but not the only, issue in introduction of HTS / MgB2 conductor into commercial MRI magnets, and in some cases the prospects for developing an MRI-ready conductor are more favorable, but significant developments are still needed.