A comparison of self field corrected to non-corrected critical current data for superconducting wires

Two different conventions have evolved for the reporting of critical currents for superconductors. It is customary to report the critical current for cables with a self field correction. Wire data are typically reported without a field correction. Ignoring the self field correction for wire testing is typically not a large effect because the sample configuration is a helix in which adjacent turns are far enough apart to have only a small effect on one another. Additionally, the current carried by the wire is often small (Ic ≤ 500 amps). Thus, with open helix configurations, the maximum field seen by a wire reduces to the equation from the Biot-Savart Law for a straight wire in a uniform magnetic field. However, some sample configurations better approximate a single layer solenoid than an open helix. For the case of a single layer solenoid, it seems appropriate to include a field correction for the reporting of the short sample data. In this work the authors provide two specific examples of correcting for the sample field on short sample test results. The first shows the effect of field correction for the VAMAS second round robin probe configuration. The second example compares field corrected and uncorrected data for a tight helix sample configuration with uncorrected data from the University of Wisconsin for their open helix sample configuration