Simulation of flux dynamics in a superconducting bulk magnetized by multi-pulse technique

Fujishiro, Hiroyuki; Naito, Tomoyuki; Oyama, Mitsuru

doi:10.1016/j.physc.2011.05.081

Cited by 7 publications

(5 citation statements)

References 8 publications

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“…The record trapped field achieved by PFM to date is 5.2 T at 29 K using a modified MPSC (MMPSC) technique [10]; unfortunately, this is still much less than the true trapped field capability of these materials. Numerical models [11]- [13] have been developed that qualitatively reproduce some of the experimentally observed results; here we extend this work to provide a comprehensive and realistic picture of multi-pulse PFM.…”

mentioning

confidence: 62%

“…Examination of the numerical results in detail permits it to be deduced that this behaviour occurs because it is more difficult for magnetic flux to penetrate the bulk due to the existing trapped field from the 1 st pulse (hence, an increased Bapp is necessary), which has a corresponding induced supercurrent that flows in the opposite direction. This also results in a lower temperature rise because of the reduced dynamic movement of the magnetic flux within the bulk (hence, Bt is higher) [13]. Figs.…”

Section: Pulsed Field Magnetisation -Multi-pulse Results -2 Nd Pulsementioning

confidence: 99%

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Toward Optimization of Multi-Pulse, Pulsed Field Magnetization of Bulk High-Temperature Superconductors

Ainslie

Srpcic

Zhou

et al. 2018

IEEE Trans. Appl. Supercond.

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Pulsed field magnetisation (PFM) is the most practical method for magnetising bulk superconducting materials as trapped field magnets (TFMs), but the record trapped field achieved by PFM to date is still significantly less than the true trapped field capability of these materials. In this paper, a flexible numerical modelling technique based on the finite element method is used to provide a comprehensive and realistic picture of multi-pulse PFM, which has been shown to be effective in increasing the trapped field/flux over a single pulse. Firstly, the maximum trapped field capability of a representative sample is determined using two types of numerical model simulating fieldcooling (FC) and zero-field-cooling (ZFC) magnetisation. Next, various sets of magnetic field pulses are applied to the bulk to analyse multi-pulse PFM. An increase in the trapped field can be achieved after a 2 nd pulse and to do so an increased amplitude of applied field is required to maximize the trapped field fully. The numerical analysis shows that this occurs in subsequent pulses because it is more difficult for the magnetic flux to penetrate the sample and there is a lower temperature rise.  Index Terms-Bulk high-temperature superconductors, finite element method, numerical simulation, pulsed field magnetization, trapped field magnets. I. INTRODUCTIONULK superconducting materials can be used as trapped field magnets (TFMs) and magnetic fields greater than 17 T have been achieved in large, single-grain (RE)BCO (where RE = rare earth or Y) bulk high-temperature superconductors [1], [2]. However, developing practical magnetising techniques is crucial to using them as TFMs in engineering applications, such as rotating machines, magnetic separation and magnetic drug delivery systems [3]- [5].Pulsed field magnetisation (PFM) is the most practical M. D. Ainslie would like to acknowledge financial support from a Royal Academy of Engineering Research Fellowship and an Engineering and Physical Sciences Research Council (EPSRC) Early Career Fellowship EP/P020313/1. Additional data related to this publication are available at the University of Cambridge data repository (

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mentioning

confidence: 62%

Section: Pulsed Field Magnetisation -Multi-pulse Results -2 Nd Pulsementioning

confidence: 99%

Toward Optimization of Multi-Pulse, Pulsed Field Magnetization of Bulk High-Temperature Superconductors

Ainslie

Srpcic

Zhou

et al. 2018

IEEE Trans. Appl. Supercond.

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“…In [141], the authors applied the numerical technique in [103] to evaluate the MMPSC technique. Extending the results above [139], the real cylindrical geometry of the sample was modelled and the time evolution and position dependence of the magnetic field and temperature were reported, in order to further understand the flux dynamics and temperature propagation when using MMPSC.…”

Section: Homogeneous Mgb 2 Bulk Superconductorsmentioning

confidence: 99%

Modelling of bulk superconductor magnetization

Ainslie

Fujishiro

2015

Supercond. Sci. Technol.

182

166

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This paper presents a topical review of the current state of the art in modelling the magnetization of bulk superconductors, including both (RE)BCO (where RE = rare earth or Y) and MgB 2 materials. Such modelling is a powerful tool to understand the physical mechanisms of their magnetization, to assist in interpretation of experimental results, and to predict the performance of practical bulk superconductor-based devices, which is particularly important as many superconducting applications head towards the commercialisation stage of their development in the coming years. In addition to the analytical and numerical techniques currently used by researchers for modelling such materials, the commonly used practical techniques to magnetize bulk superconductors are summarised with a particular focus on pulsed field magnetization (PFM), which is promising as a compact, mobile and relatively inexpensive magnetizing technique. A number of numerical models developed to analyse the issues related to PFM and optimise the technique are described in detail, including understanding the dynamics of the magnetic flux penetration and the influence of material inhomogeneities, thermal properties, pulse duration, magnitude and shape, and the shape of the magnetization coil(s). The effect of externally applied magnetic fields in different configurations on the attenuation of the trapped field is also discussed. A number of novel and hybrid bulk superconductor structures are described, including improved thermal conductivity structures and ferromagnet-superconductor structures, which have been designed to overcome some of the issues related to bulk superconductors and their magnetization and enhance the intrinsic properties of bulk superconductors acting as trapped field magnets (TFMs). Finally, the use of hollow bulk cylinders/tubes for shielding is analysed.

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“…Experimental research has remained limited and has shown little progress in exploring the enhancement of the trapped field using PFM. Therefore, we have also constructed the framework of theoretical simulation in the superconducting bulk during PFM using the solenoid coil and have simulated the time and spatial dependence of the local field B z (t, r ) and temperature T (t, r ) in the superconducting bulk for a single magnetic pulse application [13], for successive pulsed field application with identical strength (SPA) [14], and for MMPSC [15], all of which reproduced the experimental results qualitatively.…”

Section: Introductionmentioning

confidence: 87%

Mechanism of magnetic flux trapping on superconducting bulk magnetized by pulsed field using a vortex-type coil

Fujishiro¹,

Naito²,

Oyama³

2011

Supercond. Sci. Technol.

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Numerical simulations of trapped field B z and temperature T have been performed for a cryo-cooled superconducting bulk disc after applying a magnetic pulse using a vortex-type coil. Results of the simulation qualitatively reproduced experimental results reported by Ida et al (2004 Physica C 412-414 638). Using the vortex-type coil, the magnetic flux does not intrude into the bulk from the periphery but intrudes from both surfaces of the bulk disc. The temperature rise was less than that obtained when using a conventional solenoid coil. The effect of the trapped field enhancement using a long pulse application is small, which suggests that down-sizing of the condenser bank used for the pulsed field magnetization is possible and that the use of the vortex-type coil is desirable for practical applications.

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Simulation of flux dynamics in a superconducting bulk magnetized by multi-pulse technique

Cited by 7 publications

References 8 publications

Toward Optimization of Multi-Pulse, Pulsed Field Magnetization of Bulk High-Temperature Superconductors

Toward Optimization of Multi-Pulse, Pulsed Field Magnetization of Bulk High-Temperature Superconductors

Modelling of bulk superconductor magnetization

Mechanism of magnetic flux trapping on superconducting bulk magnetized by pulsed field using a vortex-type coil

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