Logarithm of number of domain cells N_cells (colour maps) in terms of magnetic field components |B_z| (three top rows) and B_h (three bottom rows) and vertical velocity υ_z in all snapshots from the SSD run of the time series of the G2V (left column), K0V (middle), and M2V (right) star. Each row shows the number of cells for a different optical depth (log τ = 0, 2, 4), indicated next to the y-axis labels at the left.