Mass-to-flux ratio μ versus radius for different grain sizes at the time of the formation of the second core. For comparison, the thin dashed line shows the case with only the simplified version of Ohmic dissipation, as used in DB10. In the center, the difference is a factor of ≈ 10², but further out it it still 2 ×  higher, and also shows a greater extent by about this factor. The reason is twofold: firstly, ambipolar diffusion is important at lower densities and, secondly, the effective resistivity is larger everywhere than the parametrization used in DB10 (cf. Fig. 2).