Properties of a new quasi-axisymmetric configuration

Abstract

A novel, compact, quasi-axisymmetric configuration is presented which exhibits low fast-particle losses and is stable to ideal magnetohydrodynamic (MHD) instabilities. The design has fast-particle loss rates below 8% for flux surfaces within the half-radius, and is shown to have a MHD stability limit of a normalized pressure of , where is volume averaged. The flux surfaces at various plasma betas and currents as calculated using the SPEC equilibrium code (Loizu et al 2016 Phys. Plasmas 23 112505) are presented. Neoclassical transport coefficients are shown to be similar to an equivalent tokamak, with a distinct banana regime at half-radius. An initial coil design study is presented to assess the feasibility of this configuration as a fusion-relevant experiment.