Magnetic energy and helicity spectra, 2μ₀E_M(k) and k|H_M(k)|, respectively, for two separate distance intervals (first and third panels). Furthermore, both spectra are scaled by 4πR² before averaging within each distance interval above and below 2.8 AU, respectively. The relative magnetic helicity, kH_M(k)/2μ₀E_M(k), is plotted separately (second and fourth panels) together with its cumulative average starting from the low wavenumber end. The zero line is shown as dashed. Adapted from Brandenburg et al. (2011).