Equilibrium optimization for the Columbia Reconfigurable EXperiment*

This study presents equilibrium optimization results for the Columbia Reconfigurable EXperiment (C-REX), a stellarator-tokamak hybrid device concept. C-REX will have an array of dipole magnets constrained to an axisymmetric surface and planar toroidal coils. In this study, we explore a range of equilibrium configurations by varying plasma parameters such as iota and plasma volume, while having sufficient distance between the last closed flux surface and the vacuum vessel wall. We also constrain our calculations to configurations with reduced surface curvature so that they are compatible with dipole magnets. The planned flexibility of C-REX will enable studies exploring hybrid configurations with low quasisymmetry errors while supporting multiple configurations simultaneously.