izentrop wrote:...
No, no electric current, otherwise there would be energy consumption.
Hello,
There is energy consumption only for a current of free electrons, in a resistive conductor. Obviously for an atom where the electron is captive, the medium seen of the electron is the vacuum, and that it is the spin or the orbital movement, no energy is dissipated.
We also do it very well also with a looped superconductor: the current flows there indefinitely once we have initiated it, generating a constant magnetic field which is maintained without energy, simply because of the current which is maintained alone.
The quote from Capt_Maloche seems relevant to me. Even on the question of electrostatics. The magnetic field is the electric field of a charge seen in displacement, and to which, relativity requires, we must apply the Lorentz transforms to obtain the local correspondence to the observer, of the electric field linked to the charge.
The electric field is isotropic seen from the charge itself, but not for the observer with respect to which it moves. It contracts in the same way as lengths contract, and it is the anisotropy linked to its displacement that gives the magnetic effect. All of Maxwell's electromagnetism can be found in this way by Einstein's relativity. Magnetic and electric fields are one and the same physical reality, but seen from different angles.