That's a lot of teslas. Your standard high-power copper coil would be torn apart at something like 25 teslas, the researchers say. That's because the magnetic field and the electric current that creates it work at cross purposes at higher energies. The current running through the coil generates the magnetic field, but the magnetic field pushes back against the electrons flowing through the coil. The stronger the current, the more the magnetic field pushes back, and once the current crosses a certain threshold the magnet will quite literally tear itself apart.