Speaker
Description
Screening currents on REBCO magnets are well known as causes of troublesome. The screening current-induced fields cause a low quality; i.e., it deteriorates the field homogeneity or generate unexpected fields. In recent years, the local high strain effect due to screening currents has been investigated. The screening current under high magnetic fields rotate REBCO tapes. It results the REBCO tape rotation with local high strain. Finally, the REBCO tapes have damages of plastic deformation together with the critical current degradation.
Meanwhile, as far as we experienced, some REBCO magnets reached to quenches at operating currents lower than the rated currents or the critical currents. We have investigated the cause of early quenches through simulations. As well known, some REBCO magnets have large screening currents induced by the self fields. The simulation results show a possibility that the screening currents generate a high heating locally. We will clarify such curious heating phenomenon through some simulation, and we will investigate its effect on the magnet stability. In addition, we will investigate some extra heating caused by the leakage currents (radial currents) of no-insulation REBCO magnets after stopping the current increasing.
