Recent advances in the design of quasiaxisymmetric stellarator plasma configurations

Strategies for the improvement of quasiaxisymmetric stellarator configurati ons are explored. Calculations of equilibrium flux surfaces for candidate c onfigurations are also presented. One optimization strategy is found to gen erate configurations with improved neoclassical confinement, simpler coils with lower current density, and improved flux surface quality relative to p revious designs. The flux surface calculations find significant differences in the extent of islands and stochastic regions between candidate configur ations. (These calculations do not incorporate the predicted beneficial eff ects of perturbed bootstrap currents.) A method is demonstrated for removin g low order islands from candidate configurations by relatively small modif ications of the configuration. One configuration is identified as having pa rticularly desirable properties for a proposed experiment. (C) 2001 America n Institute of Physics.