Influence of E–J Characteristics of Coated Conductors and Field Ramp-Up Rates on Shielding-Current-Induced Fields of Magnet

We carried out electromagnetic field analyses on the shielding-current-induced field (SCIF) of a cosine-theta dipole magnet, which is wound with coated conductors with finite electric field (E)-current density (J) characteristics and must ramp up its magnetic field. E-J characteristics, which depend on the field amplitude and orientation, were formulated based on the measured E-J data and were used for the analyses. The distributions of E in coated conductors of the magnet during the ramp-up phase as well as the flat top of the magnet excitation was revealed, and the relevant range of E-J characteristics of coated conductors was discussed from the viewpoint of dominating shielding currents. The influences of the variation of the E-J characteristic and the field ramp-up rate on SCIF were examined.