Theoretical simulation studies of pulsed field magnetisation of (RE)BCO bulk superconductors

Xu, Zhanwei; Lewin, R; Campbell, A.M.; Cardwell, D. A.; Jones, H.

doi:10.1088/1742-6596/234/1/012049

Cited by 10 publications

(7 citation statements)

References 12 publications

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“…The critical condition corresponds to that in which it is equally easy for flux to propagate to both ends of the sample by either of these paths, and the corresponding radius is hence the critical radius. In addition, both regimes are completely different from that involved in solenoidal-coil magnetization, where flux penetrates into the sample from the periphery to the centre, as shown in figure 5(b) [7].…”

Section: Influence Of Sample Dimensions On the Magnetization Processmentioning

confidence: 86%

“…Here κ is the thermal conductivity of the (RE)BCO bulk material, c is the heat capacity and ρ is the density. However, only a very small temperature rise is observed in the simulation for samples magnetized by a sufficiently long pulse at 77 K [7]. Hence, most of the results in this paper are based on the solution of the critical state equation only, in order to maintain a self-consistent system, while the solution incorporating the heat equation serves only as a 'quality control' measure for verifying the credibility of the results.…”

Section: Theoretical Modelmentioning

confidence: 97%

“…As a result, such systems and processes are analysed commonly by numerical simulation. However, existing research into the simulation of magnetization processes of bulk HTS has focused mainly on conventional geometry, in which superconducting samples are magnetized by a solenoidal coil [5][6][7][8]. Fujishiro et al [9] have compared the magnetization of bulk HTS using vortex-type split coils with that using a solenoid by numerical simulation and confirmed that enhanced trapped field and reduced temperature rise can be achieved at 40 K when the outer diameter of the vortex-type coils is smaller than that of the bulk HTS.…”

Section: Introductionmentioning

confidence: 99%

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Simulation studies on the magnetization of (RE)BCO bulk superconductors using various split-coil arrangements

Lewin

Campbell

et al. 2012

Supercond. Sci. Technol.

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Simulation studies were conducted on the magnetization of (RE)BCO (RE–Ba–Cu–O, where RE represents a rare earth element) bulk superconductors using various split-coil arrangements by solving the critical state equation using the commercial software FlexPDE. A pair of coaxial coils of identical size is identified as an optimum arrangement for practical magnetization at 77 K by the ‘zero-field cooling’ technique. In general, the magnetization process is likely to be most effective when the outer radius of the coils lies between 100% and 50% of the sample radius. A relatively large coil pair is necessary for samples with either a smaller aspect ratio or larger values of Jc0. Two different regimes of flux penetration are found to be involved in the magnetization process. For a sufficiently small sample, the penetration field is determined by flux propagation from beneath the coil to the centre of the sample; for a sufficiently large sample, the definitive propagation route is from beneath the coil to the periphery of the sample. Effective split-coil magnetization occurs only in the former regime, and both penetration regimes are completely different from that involved in the solenoidal-coil magnetization process.

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Section: Influence Of Sample Dimensions On the Magnetization Processmentioning

confidence: 86%

Section: Theoretical Modelmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Simulation studies on the magnetization of (RE)BCO bulk superconductors using various split-coil arrangements

Lewin

Campbell

et al. 2012

Supercond. Sci. Technol.

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“…Numerical simulation is a powerful tool to consider the obtained experimental results during PFM, and to understand the flux dynamics using electromagnetic and thermal equations. Several studies using the numerical simulation have been reported for PFM [17][18][19][20][21][22][23]. We have previously confirmed the advantage of the insertion of a soft iron yoke with a flat surface in the split coil numerically, and compared this to the case without the yoke [14,15].…”

Section: Introductionmentioning

confidence: 92%

Trapped field properties of a Y–Ba–Cu–O bulk by pulsed field magnetization using a split coil inserted by iron yokes with various geometries and electromagnetic properties

Takahashi

Ainslie

Fujishiro

et al. 2017

Physica C: Superconductivity and its Applications

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We have investigated, both experimentally and numerically, the trapped field characteristics of a standard Y-Ba-Cu-O bulk of 30 mm in diameter and 14 mm in thickness magnetized by pulsed field magnetization (PFM) using a split coil, in which three kinds of iron yoke are inserted in the bore of the coil: soft iron with a flat surface, soft iron with a taper, and permendur (50Fe+50Co alloy) with a flat surface. The highest trapped field, B Tmax , of 2.93 T was achieved at 40 K in the case of the permendur yoke, which was slightly higher than that obtained for the flat soft iron or the tapered soft iron yokes, and was much higher than 2.20 T in the case without the yoke. The insertion effect of the yoke on the trapped field characteristics was also investigated using numerical simulations. The results suggest that the saturation magnetic flux density, B sat , of the yoke acts to reduce the flux flow due to its hysteretic magnetization curve and the higher electrical conductivity, ,of the yoke material also acts to suppress the flux increase rate. A flux jump (or flux leap) can be reproduced in the ascending stage of PFM using numerical simulation, using an assumption of relatively high J c (T, B) characteristics. The insertion effect of the yoke with high B sat and is discussed to enhance the final trapped field from both electromagnetic and thermal points of view.

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“…A model developed from the method described by Campbell [8] and applied by Xu et al [9] for the determination of the critical state, which is based on the force-displacement curve for flux lines, was implemented in FlexPDE, a commercial finite element based software. The constitutive relation, on which the model relies, depends on the potential vector A since the vortex displacement is directly related to it, and is expressed as (assuming the current flows in the z-direction)…”

Section: A Equationsmentioning

confidence: 99%

Electro-Thermal Response of 2G HTS Coated Conductors Subjected to Current Pulses

Lacroix

Sirois

Slimani

et al. 2013

IEEE Trans. Appl. Supercond.

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Triangular-shaped current pulses were used to obtain the electrical characteristics (E−I curves) of second-generation high-temperature superconductor coated conductors above their critical current. The dependence of these E−I curves on magnetic field was also characterized (up to 150 mT). Current pulses with rising rates of hundreds of amperes per millisecond were used to minimize the heat generated in the samples. When a transverse magnetic field is applied before the current pulse, an inductive voltage is measured during the rise of the current, whose origin is explained by the presence of an asymmetric flux profile in the hightemperature superconductor layer. Results from finite-elements calculations based on a force-displacement model of the flux lines reproduced this inductive voltage, as well as the rise in samples temperature.Index Terms-Bean model, finite element methods (FEMs), flux flow resistance, high-temperature superconductors (HTSs).

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Theoretical simulation studies of pulsed field magnetisation of (RE)BCO bulk superconductors

Cited by 10 publications

References 12 publications

Simulation studies on the magnetization of (RE)BCO bulk superconductors using various split-coil arrangements

Simulation studies on the magnetization of (RE)BCO bulk superconductors using various split-coil arrangements

Trapped field properties of a Y–Ba–Cu–O bulk by pulsed field magnetization using a split coil inserted by iron yokes with various geometries and electromagnetic properties

Electro-Thermal Response of 2G HTS Coated Conductors Subjected to Current Pulses

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