Optimization of Stellarator Reactor Parameters

Four quasi-axisymmetric compact stellarator plasma and coil configurations are analyzed for their potential as reactors. A 0-D (volume-average) approach for optimizing the main reactor parameters allows study of the relationship between global parameters and the compatibility of different constraints for a given power output including plasma-coil spacing, coil-coil spacing, maximum field and coil current density, neutron wall loading, plasma beta value, etc. The result is reactor candidates with average major radii <R> in the 6-7 m range, a factor of two smaller than those of previous studies. A 1-D power balance code is used to study the ignited operating point and the effect of different plasma and confinement assumptions including density and temperature profiles, alpha particle losses, and helium particle confinement time for the different plasma and coil configurations.