Physics basis for the ARIES-ST power plant

ARIES-ST, a fusion power plant design based on the spherical tokamak concept, has many attractive features, including high beta and power density, low magnetic field and high self-driven current. The physics basis for choosing the design plasma parameters are described with respect to MHD equilibrium and stability, current drive and startup. Implications for the fusion power core design are highlighted, and key directions for ST physics research are identified.