Core of Rocky planets made of molten metal, as the planets rotates, generates magnetic fields. But how? I have seen induction equation of MHD, (both maxwell's equation and Navier-stokes equation) and can fairly clearly picture coriolis force, but none of them clearly says how exactly physically the field is created. The "seeding" of planetary magnetic field self-sustaining is attributed to stellar magnetic field.

But the problem at the root is, when molten metal exists in a solution, is not the metallic ionic core is surrounded by free electrons? Then, if the metallic ionic core and its shielding electrons that neutralize its charge move through the same path, will not the core and electron movement neutralize magnetic field of one another? When subject to magnetic field, does the electron and nucleus remain effectively detached and follow different path due to different mass-charge ratio, same like an electromagnetic pump that pumps electrons and nucleus at opposite direction, so a net mass transfer via electrons occur?

Yet again, if Lenz' Law states nature of induced magnetic field to work against agent that had created the magnetic field, then how the planetary magnetic field is self-sustaining?

yet again, how exactly the energy convection current of molten metals at core is being converted into magnetic energy? I know earth is slowing down on Geological time scale. during Cambrian, earth day was about 20 hours, and 3 billion years ago, it was 15 hours. But is not the slowing predominantly due to tidal effects between earth, moon sun and other planets? if magnetic field sustaining also has a role here, then how much?

Please include links for introduction to spherical harmonics and multipole expansion.