Dynamics and Critical Currents in Fast Superconducting Vortices at High pulsed Magnetic Fields

Leroux, Maxime; Balakirev, Fedor; Miura, Masashi; Agatsuma, K.; Civale, L.; Maiorov, B.

doi:10.1103/physrevapplied.11.054005

Cited by 9 publications

(5 citation statements)

References 47 publications

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“…That kind of vortex escape retention from columnar pinning sites probably should significantly affect vortex dynamics in rapidly varying magnetic field (comparatively to that in common superconductors with point-like vortex pinning sites, where τ r goes to zero). Such experiments in rapidly varying magnetic fields now are of great interest [14,15]. Also the delay in vortex depinning from columnar defects discussed in the present work is important for operation of current switch devices (see, e.g.…”

Section: Resultsmentioning

confidence: 73%

Numerical Simulation of Abrikosov Vortex at Columnar Defect in Superconductor

et al. 2019

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We report a numerical modeling of single vortex depinning and its subsequent dynamics in HTS film with extended linear defects under the influence of the transport current. Numerical simulation of stable pinned vortex state and its escape from a linear defect has been performed. The non-stationary dynamics of vortex escape has been investigated and time-dependent solution for vortex displacement from the defect has been obtained. The delay effect in vortex escape process has been studied and the time delay has been estimated. The impact of processes being studied on electrodynamic properties of a superconductor has also been discussed. The dynamics of vortex escape from columnar pinning site described in the present work is important both for understanding of vortex dynamics and applying high-Tc superconductors with columnar defects.

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Section: Resultsmentioning

confidence: 73%

Numerical Simulation of Abrikosov Vortex at Columnar Defect in Superconductor

et al. 2019

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“…The critical current limitation was investigated by many researchers, but mainly in the context of superconducting magnet windings and high magnetic field application. In [ 25 ], the significant influence of the fast magnetic pulses on the critical current was described. The influence of microstructure and grain boundaries on the critical current was described in [ 26 , 27 ].…”

Section: Design Of the Busbar Compensation Loopmentioning

confidence: 99%

Investigation of Mechanical Strains in Thermal Compensation Loop of Superconducting NbTi Cable during Bending and Cyclic Operation

Iluk¹

2021

Materials

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In the paper, the thermal compensation loops on a composite, superconducting NbTi cable were investigated. This type of cable is used in the superconducting, fast ramping magnets of the SIS100 synchrotron, part of the Facility for Antiproton and Ion Research (FAIR) under construction in Darmstadt, Germany. The influence of space restrictions and electromagnetic cross-talk on the design of the thermal compensation loop was discussed. Plastic deformation of cable components during bending was analyzed by numerical simulations and experiments. A three-dimensional numerical model of the cable was prepared with individual superconducting wires in contact with a central cooling pipe. The bending of a straight cable into a compensation loop shape was simulated, followed by cyclic operation of the cable during thermal cycles. The maximum strains in the superconducting strands and cooling tube were analyzed and discussed.

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“…This means that transport resistance measurements of HTS tapes do not produce a well-defined threshold value for the transition from the zero-resistance state. Instead, the conventional approach is to define the transport critical current of an HTS tape as the current at which the resistive voltage drop across the conductor is equal to 1 µV cm −1 [2,10,11]. Herein, we refer to this value as I c,µV .…”

Section: Introductionmentioning

confidence: 99%

Below 1 µV cm⁻¹: determining the geometrically-saturated critical transport current of a superconducting tape

Brooks¹,

Ainslie²,

Mataira³

et al. 2021

Supercond. Sci. Technol.

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In the critical state model, the critical current, , of a superconductor defines the upper limit of dissipation-free current flow. However conventional transport measurements of practical superconductors rely on the detection of a voltage drop along the length of the conductor. This requires that the superconductor has entered the dissipative regime, and hence inherently over-estimates the current at which geometric saturation occurs. Nonetheless, the convenience of the 1 µV cm−1 criterion means that it has become the widely adopted definition of transport . Here, we present an alternative definition for the transport critical current of a superconducting tape under self-field conditions, which is based on the concept of geometric current saturation across the full cross-sectional area. This saturation threshold can be experimentally determined through simple Hall sensor measurements of the evolving perpendicular magnetic field at the tape surface. The surface field exhibits a signature transition when the transport current increases beyond the current-saturation threshold. We present an analytical model which describes this effect and defines the critical saturated current as a function of . This definition is first validated using finite element (FE) modelling, and then experimentally demonstrated through measurements on a variety of commercial REBCO and Bi-2223 tapes of differing widths. It is found that the 1 µV cm−1 criterion consistently leads to an overestimation of the saturated critical current by ∼15% in REBCO tapes, and up to 30% in a Bi-2223 tape. FE modelling indicates that this overestimate is most prominent in superconductors exhibiting a low n-value (i.e. n ≲ 20). A key advantage of the measurement approach presented here is that it allows the unambiguous measurement of a transport value to be completed at lower currents, without entering the dissipative region in which sample damage can occur. There are also implications as to the correct choice of value which should be employed within the well-known Norris and Brandt equations for AC loss.

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Dynamics and Critical Currents in Fast Superconducting Vortices at High pulsed Magnetic Fields

Cited by 9 publications

References 47 publications

Numerical Simulation of Abrikosov Vortex at Columnar Defect in Superconductor

Numerical Simulation of Abrikosov Vortex at Columnar Defect in Superconductor

Investigation of Mechanical Strains in Thermal Compensation Loop of Superconducting NbTi Cable during Bending and Cyclic Operation

Below 1 µV cm⁻¹: determining the geometrically-saturated critical transport current of a superconducting tape

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Dynamics and Critical Currents in Fast Superconducting Vortices at High pulsed Magnetic Fields

Cited by 9 publications

References 47 publications

Numerical Simulation of Abrikosov Vortex at Columnar Defect in Superconductor

Numerical Simulation of Abrikosov Vortex at Columnar Defect in Superconductor

Investigation of Mechanical Strains in Thermal Compensation Loop of Superconducting NbTi Cable during Bending and Cyclic Operation

Below 1 µV cm−1: determining the geometrically-saturated critical transport current of a superconducting tape

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Below 1 µV cm⁻¹: determining the geometrically-saturated critical transport current of a superconducting tape