Investigation of the Inter-Coil Structures Influence on the Mechanical Behavior of the TF Magnet in a Tokamak Machine

The tokamak machine is an effective solution to achieve fusion magnetic confinement and is suitable to be adapted to a wide range of plasma performances and scenarios. Due to the high current led and to the relevant magnetic field obtained in the most demanding devices, the toroidal field (TF) coils are among the key components in such machines. For this reason, they have to be carefully designed to withstand the huge loads due to the Lorentz forces during operation. This paper deals with the effects that the inter-coil structures have on the distribution of loads and on the stress and displacement peak on the TF coil. A conceptual magnet system, which is characterized by a symmetric D-shaped TF coil plus a set of six poloidal field (PF) coils, and a reference plasma scenario have been chosen as a base for a parametric investigation by varying the position and the stiffness of the upper, lower, and intermediate inter-coil structures. The proposed approach is suitable to support the engineers in optimizing the force distribution between the coils and in improving the structural behavior.