Difference rate for all orders and degrees of the gravitational harmonics coefficients that are involved in our POD simulations. Panels a and b: present the case marked by m₀ = 2, belonging to the strong-field dynamo category, and the case marked by m₀ = 9, belonging to the weak-field dynamo category, respectively. In either panel, the left part plots the different rate of coefficients, and the right part plots the rate of . The zeroth-order coefficients are in essence the zonal harmonics coefficients . In the case shown in panel a, the input gravitational harmonics coefficients are all null, except for nonzero zonal coefficients of all degrees and nonzero . In the other case of panel b, the modeled nonzero tesseral and sectoral coefficients become . The difference rate only applies to coefficients that are assumed to be nonzero, as highlighted in all panels by boxes with dashed black edges.