Top panels: convective velocities v _c estimated for the MESA cooling WD models of 0.6 (pink and orange) and 0.9 M _⊙ (blue and green), obtained from the numerical solution of equations for the MAC balance (12) and the relation between v _c and the convective efficiency Γ (14). Bottom panels: magnetic field strength derived from the convective velocities obtained in the top panels as shown by Equation (15). For both sets of panels, we show the cases for different assumptions of the rotation period P _rot and the initial size of the convection zone R _out,0 (see legends for more details).