Analysis of Coupled Electromagnetic-Thermal Effects in Scanning-Magnet for SESRI

High frequency and magnetic rigidity are the requirement of accelerators for scanning magnets. The scanning magnets for the SESRI (the Space Environment Simulation and Research Infrastructure) project are excited by triangular currents with a maximum repetition frequency of 200 Hz. It is inevitable to produce eddy currents inside the iron yoke, especially at the pole end. The temperature rise will be caused by eddy current loss, damaging the insulation layer in coils and adhesive resin in the core. To ensure the successful design and long working life for the scanning magnet, it is essential to optimize the eddy-current losses and temperature rise. This paper provides the optimization method for the scanning magnet, describes the analysis method of eddy-current loss induced temperature rise in detail, and then the distribution of the eddy current and temperature on the yoke is calculated by the software of OPERA-ELEKTRA/TR. Meanwhile, the temperatures at some critical points of the scanning magnet were measured. The computed results verified the feasibility of the electromagnetic-thermal coupling analysis method, which agreed well with the experimental data.