Radial magnetic field at the top of the Earth's core from a high resolution numerical simulation

Snapshot of the radial magnetic field at the top of the core, from a high resolution simulation employing spherical harmonics up to degree 893 and 1024 radial levels.
The Ekman number is E=nu/(D^2.Omega) = 10^(-7) and the magnetic Prandtl number is Pm=nu/eta=0.1