A new code, Magnetic field solver for Finite-Beta Equilibria (MFBE), has been developed. It computes the magnetic field in a form suitable for field line tracing inside and outside the plasma boundary of finite-β Helias equilibria calculated with the NEMEC free boundary equilibrium code. Coupling of the NEMEC and MFBE codes allows a determination of the last closed magnetic surface. For various beta values up to (β) ≃ 0.04, the variations of the island sizes and positions outside the plasma boundary and the ergodization of the edge region are studied for a Helical Advanced Stellarator (Helias) configuration (Nuhrenberg and Zille, Phys. Lett. A 114 (1986) 129)
Determination of the magnetic field B in vacuum for general two-dimensional MHD-equilibria