Conductor on round core (CORC®) wires are attractive assembled conductors for applications to accelerator magnets because of their large current capacity and mechanical flexibility. Because the accelerator magnets are required to generate accurate time-dependent magnetic field, the complex configuration of coated conductors constituting CORC® wires and magnetization of the coated conductors could be serious problems for the field quality of the magnet.

 Electromagnetic field analysis is a convenient tool to evaluate the field quality influenced by shielding-current-induced field (SCIF) of HTS magnets. However, due to CORC® wires’ three-dimensional geometry, the analysis with high accuracy is difficult for magnets wound with CORC® wires. To solve this problem, we start to construct simple calculation method to evaluate field quality of magnets wound with CORC® wires. First, we conduct electromagnetic field analysis of one single CORC® wire having infinite length under external magnetic field. Here, Time-evolution of external magnetic field simulates magnetic field seen by a CORC® wire in the magnet. Additionally, we consider the three-dimensional geometry of the CORC® wire in this analysis. Second, we arrange the CORC® wires to make the same cross-section of the straight section of magnet. Namely, we modelled the analyzed magnet as the bundles of the CORC® wires having analyzed non-uniform current distribution in the first step. We call this model quasi-3D model. At last, we can calculate magnetic field distribution in beam region and discuss the influence of CORC® wires’ geometry and magnetization on field quality. We will report the calculation results by this model applied to some magnets.

This work was supported by JSPS KAKENHI Grant Number JP20H00245.

Keywords: CORC wire, SCIF, electromagnetic field analysis, accelerator magnet