Ratio between the synthetic Stokes U signals at the red component (λ_R) and the blue component (λ_B) for a magnetic field strength of 1 G (upper panel) and 100 G (lower panel). Horizontal dashed lines indicate the two Van Vleck angles at θ_B = 54.74° and θ_B = 125.26°. The label at the top of each panel indicates the area percentage that is covered by a positive ratio. Contours indicate the areas where Stokes U(λ_R) > 1.5 × 10⁻³ I_c.