Distributed inter-strand coupling current model for finite element simulations of Rutherford cables

Abstract In this paper, we present the distributed inter-strand coupling current (DISCC) model. It is a finite element (FE) model based on a homogenization approach enabling efficient and accurate simulation of the transient magnetic response of superconducting Rutherford cables without explicitly representing individual strands. The DISCC model reproduces the inter-strand coupling current dynamics via a novel mixed FE formulation, and can be combined with the reduced order hysteretic magnetization and flux models in order to reproduce the effects of internal strand dynamics: hysteresis, eddy, and inter-filament coupling currents, as well as ohmic effects. The DISCC model offers a massive reduction of the computational time compared to fully detailed FE models and still accounts for all types of loss and magnetization contributions. As a result, Rutherford cables homogenized with the DISCC model can be directly included in FE models of magnet cross-sections for efficient electro–magneto–thermal simulations of their transient response. We present two possible FE formulations for the implementation of the DISCC model, a first one based on the h – φ -formulation, and a second one based on the h – φ – a -formulation, which is well suited for an efficient treatment of the ferromagnetic regions in magnet cross-sections.