Evolution of Scenario C during the RGB around the H-shell (solid black line). The magnetic mass ℳ_C ∼ 0.26M_⊙ is shown as a solid red line. Left: Contour map of the magnetic flux in log-scale as it evolves according to Eq. D.17. Middle: Contour map of r⁻² in log-scale. Right: Contour map of b_r in log-scale as a result of multiplying the two panels above. The dashed black line shows the location of the maximum of b_r.