Concept of the divertor of a fusion neutron source based on a spherical tokamak

A concept of the divertor and the technology for organizing the edge plasma in a fusion neutron source based on a spherical tokamak (FNS-ST) are described. The experimental data on the characteristics of the peripheral plasma in modern tokamaks are extrapolated to the FNS-ST conditions with the help of semi-analytical models. The effects depending on the magnetic configuration and on the geometry and materials of the divertor and the first-wall elements are considered. Possible designs of the FNS-ST divertor and the first wall are described. Using an original model, it is shown that the maximum density of the heat flux at the divertor plates in a double-null magnetic configuration does not exceed 5–6 MW/m2, which complies with modern engineering capabilities. Methods for further improvement of the FNS-ST divertor concept are analyzed.