Self-field critical current of a conductor with an elliptical cross-section

Abstract

Numerical calculations using the commercial finite-element code FEMLAB have been carried out to find the distribution of current density in a wire of elliptical cross-section from a hard superconductor carrying the critical current. Dependence of the critical current density on local magnetic field and its orientation has been taken into consideration in these calculations. The results of critical current calculations for wires of different shapes and dimensions clearly revealed how this quantity can be influenced by the distribution of the self magnetic field. The outcome found for wires with cross-sections resembling tapes made from a high-temperature superconductor Bi-2223 have been approximated by two engineering formulae: one can be used to cancel out the influence of the tape width, and the other allows us to perform a correction on the aspect ratio. These expressions would allow the quality of superconducting properties expressed by the self-field critical current density to be compared also for wires of different cross-sections.

A parameter-free method to extract the superconductor’sJc(B,θ) field-dependence from in-field current–voltage characteristics of high temperature superconductor tapes

“…In this paper, in order to solve the forward problem, we solve the following equation (as proposed in [9,10])…”

Critical current measurement for design of HTS DC power cables

“…The relationship between critical current density and magnetic flux density, which was required for the program, was obtained by the formula proposed by Gömöry et al [1]. In the equation, four parameters which should be determined by experiments were required and were obtained by the measurements of the critical currents with respect to the external magnetic field.…”

“…The critical current of an HTS tape is calculated by an iterative procedure in the program based on the method proposed by Gömöry et al [1]. In the program, a model of an HTS tape is divided into small elements as shown in Fig.…”

“…Here, a phenomenological expression between the critical current density and the magnetic flux density proposed by Gömöry et al [1] is adopted, which is…”

“…The formula proposed by Gömöry et al [1] was adopted to reveal this relationship in this study, which was a phenomenological relationship between the magnetic flux density and the critical current density of an HTS tape based on the Kim formula [8] expressing the magnetic field dependence of the critical current density. The four parameters are used in the formula proposed by Gömöry et al [1], which were also obtained based on the method proposed by Gömöry et al [9]. The critical currents of a single HTS tape were measured with respect to the magnetic field applied externally to the HTS tape from different directions.…”