Relative energies of the poloidal and toroidal harmonic modes for the magnetic field topology of HD 24712. In panels one to three we show the relative energies of the magnetic field from individual MDI of Fe, Nd iii, and from simultaneous MDI of Fe, Nd iii, and Na (final model). The energy of the poloidal and toroidal modes in each panel are shown in dark and light gray. The first bar in each panel for the corresponding energy mode (poloidal, toroidal) is for ℓ = 1; the second such bar represents the sum for all energies with ℓ ≥ 2.