Influence of External Magnetic Field on AC Losses at EF Coil Joints of JT-60SA

We experimentally and numerically evaluated the AC loss occurred in joints of the EF coil in JT60-SA. There are two kinds of the joints (pancake joint and terminal joint) in the EF coil. Firstly, the AC losses of the joints were experimentally obtained. The experimental results showed that the AC losses in the pancake and the terminal joints were smaller than the loss in the prototype joint which was the previously designed joint and we measured the loss data in two years ago. And next, we numerically analysed the AC loss of the joints. The simulated results well agreed with the experimentally measured data. And we numerically tried to decrease the loss. The AC loss could be decreased to be half of the initial loss.