Critical current statistical distribution and voltage–current characteristics in superconducting wires

Abstract

Type II superconductors, like Nb-Ti and Nb 3 Sn, play a central role in the design of magnets for fusion and particle accelerators. These materials show experimentally a longitudinal electric field which depends in a nonlinear way on the current. Different models have been developed to analyse this phenomenon, mainly based on the role of defects and inhomogeneities in the superconducting sample. Some of these models are based on a statistical description of the critical current distribution along the wire, that can explain the presence of a curvature in the volt-ampere characteristic (VAC). In the work we have studied the impact of different critical current statistical distributions on the VAC and their implications, and compared some experimental data with our theoretical results.

Intrinsic and extrinsic pinning in NdFeAs(O,F): vortex trapping and lock-in by the layered structure

“…S3). In general, in case of random isotropic pinning, n scales with J c , as experimentally shown in many compounds (YBCO3839, MgB 2 40, Nb 3 Sn414243, Nb-Ti43), independently of temperature, field or angle. A relation of the type n  ∼  J c α was suggested and means that an increase of J c leads to an increase in the n -value.…”

Microscopic origin of highly enhanced current carrying capabilities of thin NdFeAs(O,F) films

“…for MgB 2 , NbTi, and Nb 3 Sn. [53][54][55] Accordingly, an increase of J c leads to an increase in the N value, and as a consequence J c (H) and N(H) should have similar trends. For Hkab, the 22 nm NdFeAs(O,F) lm (Fig.…”

Application of active quenching of second generation wire for current limiting

“…where the I-Vcurve is determined by the predictable band-gap, the I c value of a superconductor depends on many intrinsic and extrinsic factors. Moreover, an applied conductor cannot be adequately described by a single I c value; rather one should use a statistical distribution of I c values along the length of the conductor [18,19]. Traditionally I c is identified at the onset of dissipation at an electric field strength of 1 V/cm.…”