Study of Hysteresis Losses in Partial Penetration Oscillations Through Experiment, Analytical Algorithm and New Numerical Tool

In this paper, we aim at describing the hysteretic losses in superconducting conductors in the specific case of multiple field reversals in partial penetration, which produces a complex field profile in the superconductor, and which happens quite extensively in complex field scenarios like those of fusion magnets. The paper will introduce the usual analytical formulas used for computing the hysteresis losses, pointing out their limits, before explaining the specific algorithm implemented to use these formulas in alternating partial penetration fields. An experiment on the JT60-SA TF superconducting cable has been performed, in the Josefa facility at CEA, with a field variation explicitly trying to reproduce multiple partial penetration field reversals. The analysis of the experimental curves and results is presented and compared with analytical and the new numerical code. This new tool called FLASH has been built to describe precisely the field penetration of any external field waveform in partial or full penetration. The main hypotheses of the tool are briefly described, along with examples of outputs for simple field variations that serve as cross-check and validation of the code.