Force free magnetic fields in a type II superconducting cylinder

Walmsley, D.G.

doi:10.1088/0305-4608/2/3/020

Cited by 105 publications

(61 citation statements)

References 10 publications

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“…The idea of flux cutting was first introduced [11,52] to explain unexpected voltage oscillations in current carrying SC wires in the axial magnetic field. Since then, the force free configurations and transverse vortex motion in longitudinal currents were addressed in many theoretical works but still remain a hypothetical concept.…”

Section: Flux Cuttingmentioning

confidence: 99%

Flux cutting in high-Tcsuperconductors

et al. 2015

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We performed magneto-optical study of flux distributions in a YBCO crystal under various applied crossed-field orientations to elucidate the complex nature of magnetic flux cutting in superconductors. Our study reveals unusual vortex patterns induced by the interplay between flux-cutting and vortex pinning. We observe strong flux penetration anisotropy of the normal flux B ⊥ in the presence of an in-plane field H || and associate the modified flux dynamics with staircase structure of tilted vortices in YBCO and the flux-cutting process.We demonstrate that flux-cutting can effectively delay vortex entry in the direction transverse to H || . Finally, we elucidate details of the vortex-cutting and reconnection process using time-dependent Ginzburg-Landau simulations.

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Section: Flux Cuttingmentioning

confidence: 99%

Flux cutting in high-Tcsuperconductors

et al. 2015

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“…2'3 Flux-flow resistance is observed also in long cylinders carrying a current parallel to an applied axial magnetic field. [4][5][6][7][8][9][10][11][12][13][14][15] In spite of considerable effort, 3'16-24 a satisfactory explanation of flux-flow resistance in longitudinal geometry has not yet been given. Any microscopic mechanism for voltage generation by FLs moving at a velocity v inevitably leads to "force-free 33 configurations" in which the FLs are parallel to the local current density j everywhere.…”

Section: Introductionmentioning

confidence: 99%

Longitudinal critical current in type II superconductors. I. Helical vortex instability in the bulk

Brandt

1981

J Low Temp Phys

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The vortex lattice in type H superconductors is unstable against the growth of helical perturbations if the current along the vortices exceeds a critical value. The longitudinal critical current, the pitch, and the spatially varying amplitude of the elliptically polarized helices are calculated from the London theory at the onset of instability in planar current distributions far from the surface. For weak pinning (atA 2 << C66) the wavelength and width of the mode extend over 1/4 the entire specimen, and the critical current is 2H(c66/c11) . For moderate pinning (c66 << aLA 2 << C11) the wavelength and width are close to Campbell's pinning length (c11/az)1/2, and the critical current times its mean density is 2 ~/2 . • 2 >> .... 2H (aL/C11) . For strong pmnmg (OLLI~ Cll ) hehcal mstabthty occurs at pin-free vortex sections, the helix wavelength is 2.2d, and the critical current density is 0.47Hd/A 2 (H, d, cll and C66 , and aL are the magnetic field, spacing, elastic moduli, and pinning parameter of the vortex lattice, and ~ is the magnetic penetration depth).

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“…Walmsley [10] measured the magnetization and the axial resistance of a type-II superconductor -in mixed state and with cylindrical geometry-by subjecting it simultaneously to a magnetic axial field and a transport current, parallel to each other. The objective was to prove under what the Lorentz force density could be null.…”

Section: Flux-line Cuttingmentioning

confidence: 99%