Verification of the Finite Element Model of the Magnet System of the Globus-M2 Spherical Tokamak Based on the Experimental Data

This paper presents the verification of results of the stress analysis of the Globus-M2 spherical tokamak magnet system on the basis of measurements carried out in experiments. The magnet system is composed of toroidal and poloidal field coils and intercoil and supporting structures and is subjected to the impact of electromagnetic (EM) loads during an experiment. In the series of experiments with close to maximum values of the plasma current and toroidal field, the toroidal field coil displacements in the toroidal direction under EM loads with respect to its natural position were measured using a high-speed camera. The EM loads were determined using a 3D model of the Globus-M2 tokamak magnet system from the currents of the toroidal and poloidal field coils and plasma measured in experiments. These loads were used for the stress analysis of the Globus-M2 magnet system in the ANSYS software. Results of this work show that the approach consisting of two stages—the reconstruction of the EM loads and the determination of the mechanical response of the structure—was successfully verified for the EM system of the Globus-M2 and can be used for other tokamaks.