Length scale of the Tayler instability mode measured in the simulations (black stars) as a function of N/Ω_o. The theoretical lower (l_min in blue) and upper boundaries of the length scale are also plotted using the classical (l_max,  N in orange) and the effective (l_{max,  Neff} in red) Brunt-Väisälä frequencies. Filled and empty markers represent self-sustained and transient dynamos, respectively.