Computation of Current Distribution in YBCO Tapes With Defects Obtained From Hall Magnetic Mapping by Inverse Problem Solution

Abstract

The development of superconducting devices based on long-length HTS tapes often requires of these tapes high homogeneity along its length as well as across its width. This implies the absence of significant local defects. Non-destructive characterization techniques to examine critical current distribution for defect detection are of great interest, specially if they could be applied in situ for real-time testing of large lengths of tape. In this work, we continue the adaptation of our method for the computation of critical current maps from Hall measurements of the magnetic field over the tape. We compute the current density distribution in a stretch of a commercial YBCO tape which contains defects by using a specifically designed fast inverse problem solver. The 2-dimensional current map meshes with the current distributions in a cross-section of the tape that we previously computed in real time, so that a map of the critical current circulating on the entire surface of a tape with isolated defects may be obtained, regardless of its length, by running a Hall probe over it. This method is applied to a series of Hall mappings corresponding to several magnetization regimes, produced by applying different current intensities to the tape. Details of the experiments and the calculation method are reported and the applicability to detect the impact of the defects in the tape over the current distribution is discussed.