ElectroMagnetic (EM) radiations of Integrated Circuits (IC) is for many years a main problem from an ElectroMagnetic Compatibility (EMC) point-of-view. But with the increasing use of secure embedded systems, and the apparition of new attacks based on the exploitation of physical leakages of such secure ICs, it is now also a critical problem for secure IC designers. Indeed, EM radiations of an IC, and more precisely the magnetic component, can be exploited to retrieve sensible data such as, the secret key of cryptographic algorithms. Within this context, this paper aims at introducing a magnetic field simulation flow allowing predicting, with high spatial and time resolutions, the magnetic radiations of IC cores. Such a flow being mandatory to predict the robustness of secure ICs before fabrication against EM attacks.