Structural analysis of a high field confinement experiment

A detailed stress analysis of the toroidal magnet and of the central element of the transformer of the ignitor device, in which these two components are mechanically coupled, was performed. Only the elastic regime was considered. A radial loading was applied on the outer edges of the vertical plates that compose the toroidal magnet, in order to reduce the stress in its internal throat region. Several values for the corresponding radial pressure were tried and the optimal value was found to be about 150 MPa. The stress distribution of the whole structure was evaluated, by a finite element code, for the entire evolution of a typical plasma discharge. It was found that, with the hypothesis made, in all the cases considered the von Mises equivalent stresses, in the conducting turns are below the yield stress of copper at the temperature considered. The stresses in the supporting steel structure are always less than a half of yield stress of steel