If that is true then how does Jupiter have the largest magnetic field in the solar system Besides the Sun? Jupiter doesn‘t have any solid surface. Where is the magnetic material generating the field?
The core doesn't have to be iron. It has to be metallic, and under the extreme conditions at the core of Jupiter its thought that hydrogen acts as a liquid metal.
On the Discovery Channel a month or so ago, they went into the question of *why* Jupiter has such a strong magnetic field (it almost stretches to the orbit of Saturn, in fact.) It's thought that the behavior hydrogen under huge pressures makes it almost metallic - crystalline, and *can* arrange itself such that a magnetic field is produced. Try this link: csep10.phys.utk.edu/astr161/lect/.
No. However, an iron core would enhance the magnetic field generated. Metallic hydrogen is paramagnetic, and there's a lot of hydrogen on Jupiter.
