Results of simulations for different values of ohmic and thermal diffusivities (η = 10⁶−10¹⁰ cm²/ s, κ = 10⁵−10¹² cm²/ s) and for a poloidal magnetic field amplitude of 5000 G. Green dot are simulations for which the tachocline is confined, while red dots are not confined. The solid and dashed lines indicate respectively the approximated transition between confined and unconfined tachoclines and the simulations where κ/η = 1. The dash-dotted line labels Γ_κ = 1 (see Eq. (16))