Coil induced eddy current analysis of a fast kicker magnet

The eddy current effect is an important issue in pulsed magnet design. The eddy currents in the iron cores and the metal supports are proven to be the major causes of the eddy current effects in accelerator magnets. In our previous study, we focused on the eddy current effects in yoke and metal supports of a fast kicker magnet in Huazhong University of Science and Technology (HUST). Simulations using OPERA 3D revealed that eddy currents in yoke and metal supports have no significant influence on the magnetic field quality. However, the measured magnetic field distortion is approximately ± 0.4% during the fast change of magnetic field, and it takes several hundreds of microseconds to disappear. In addition, it is difficult to achieve a fast transient from the rising process to a steady state. Herein, we investigate the coil induced eddy current effect of a fast kicker magnet and reveal the main reason for the field distortion and the difficulty in the pulsed power supply commissioning. With design considerations of the coil induced eddy current, the simulation results can be in good agreement with the measurement results. Based on the dynamic performance of the load inductance, a fast transient from the rising process to a steady state can be achieved. The research findings can provide a good reference in the design and optimization of such pulsed magnet and associated power supply, especially for the fast kicker/bump magnet with windows frame yoke.