Simulation of Magnetic Fields in the MEPhIST-0 Tokamak at the Beginning of Discharge

A model for calculating the distribution of poloidal magnetic fields in the MEPhIST-0 tokamak implemented in the COMSOL Multiphysics environment is presented. The model makes it possible to calculate the spatiotemporal distribution of poloidal magnetic fields according to a given dependence of the current in the elements of the tokamak magnetic system versus time, taking into account a conductive vacuum chamber and a toroidal solenoid with a preferential direction of the toroidal current component. The parameters of the model were selected on the basis of experimental data on the distribution of the poloidal magnetic flux obtained using the voltage loop of the MEPhIST-0 tokamak. Using the developed model for calculating magnetic fields, a set of input parameters of the tokamak pulse is selected for which the discharge is successfully initiated.