Fig. 4From: Evaluation of candidate geomagnetic field models for IGRF-12Lowes-Mauersberger spectra i,M R n from Eq. 5 of the difference between the IGRF-2015 candidate models and the simple arithmetic mean model M at the Earth’s mean radius r=a. The right plot shows the azimuthal power spectrum i,M R a of this differenceBack to article page