Magnetic field modeling for Mercury using dynamo models with a stable layer and laterally variable heat flux

Mercury's surface magnetic field is unique among planetary magnetic fields for its weak intensity, spin-aligned axisymmetry, and large dipole offset. An Earth-like dynamo setup applied to Mercury does not reproduce these features. Here we explain the magnetic field observations by a combination of two effects: (1) a stably stratified layer at the top of the outer core, and (2) a degree-1 north-south asymmetric spherical harmonic heat flux variation at the core-mantle boundary (CMB). We vary the stable layer thickness and size of the inner core, and find models that can produce surface magnetic fields possessing the observed features of Mercury.