Title: Confinement Analysis of Spherical Tokamak-Stellarator Hybrid Configurations with Simple Shaped Coils
Abstract: Six types of spherical tokamak-stellarator hybrid configurations with simple shaped coils “TOKASTAR”, are proposed and analyzed in terms of magnetic flux surface, equilibrium and fast particle confinement. It was found that TOKASTAR can produce flux surfaces with low averaged aspect ratio. The averaged rotational transform are low but local value is relatively high, especially at the outboard side. In the equilibrium beta limit analysis it was clarified that TOKASTAR can achieve high equilibrium beta with relatively low plasma current. In the fast particle confinement analysis, it was found that the fraction of confined alpha particles in the reactor-sized TOKASTAR is 40∼60%.