Geodynamo

The geodynamo is the maintenance of Earth's magnetic field by electrically conducting fluid motion in its liquid outer core. Rotation and buoyant convection organize helical flow and permit mean-field poloidal–toroidal regeneration. A scalar homogeneous alpha model explains a mechanism and a threshold but omits spherical boundaries, anisotropy, spatial variations and Lorentz force feedback. Reversals and saturation require dynamical or time-dependent transport information beyond a growing constant-coefficient kinematic mode.