Sometimes changing the perspective can make a number of things clear.
The idea that the Earth's magnetic field has something to do with the Earth's core
has impeded understanding this electromagnetic phenomenon. A better analogy would
be comparing the Earth's magnetic field with corona discharge photography or the Kirlian effect.
Under a enormous electric current the structure of the Earth's magnetic field would be dependent
on the marcostructure of the Earth. In other words: the Earth is "moist" and this
is the source of the particles or plasma that circulates in the Earth's magnetic field.  Water
ionized or destroyed via ultra violet rays in the ionosphere provides the protons and electrons for this plasma.
Most of the electric currents we are familar with consist of electrons circulating in metal wires,
but a stream of protons would generate an magnetic field as well.
Remember hydrogen is the only element whose atomic number and weight are identical. There is no neutron associated with
an atom of hydrogen. Therefore, ionized hydrogen or a proton are the same item.
This self assembling system is well known in the science of chaos.
The Kirlian effect needs an electric current. So where does
the initial electricity come in? While I am not an expert in the Electric Universe. There are
quite a few articles explain that the solar wind is actually electrical in nature. The solar wind
would provide enough volts to "light up" Earth's magnetic field.

Imagine an experiment on a planetary scale. Some god-like aliens have decided to take some
Kirlian photos of asteriods. Those that are dry rock like, Mars or Mercury ,
produce very little in the  way of  a magnetic field  seen in complex structure of  corona discharge
photography. However, icy asteriods or those composed largely of hydrocarbons would "fluoresce".
Rotate these hydrogen rich planetoids and you have what amounts to  a bipolar motor with a North and South pole.
What is nice about this theory is that it is testable. It does not rely on the existance of a huge molten
ball of iron that acts in  mysterious ways. Students and professors around the globe can make physical or virtual
models and simulate to their hearts content.