Fit of the sixth order numerical diffusivity coefficient . Left: Scatter plot showing the dependence between the terms of the induction equation, y = ∂B/∂t − ∇ × v × B (vertical axis) and s = Δ⁶B (horizontal axis). The intensity of the color indicated the number of spatial data points with the given values of (s,y) in log₁₀ units. The green line shows the linear fit to the distribution, with the value of the slope indicated in the figure. Right: Dependence of the slope on the spatial mode number, obtained after the fitting to the simulation data (as those from the left panel) for three simulations with different values of the filtering frequency: every 1 time step (green line), every 5 time steps (red line), and every 20 time steps (black line). The dependence on the mode number is obtained after applying a 2D Fourier high-pass filter to y = ∂B/∂t − ∇ × (v×B) and s = Δ⁶B variables in each case.