Non-thermal to thermal energy budget as a function of the central magnetic field in a pure hadronic model. The dashed, dotted, and solid lines are the CRe to ICM energy ratio, the magnetic to ICM energy ratio, and the total non-thermal to ICM energy ratio, respectively; these are required to match the observed radio emission up to radii of 2.2r_c (lower dashed and solid lines) and 2.5r_c (upper dashed and solid lines). The non-thermal energy budget for typical values of B₀ ≲ 10 μG in galaxy clusters is indicated by the yellow area. A pure hadronic model would require unrealistically high values of (ε_CR+ε_B)/ε_ICM and/or B₀.