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  1. Standard member sonhouse
    Fast and Curious
    15 Apr '16 13:47
    http://phys.org/news/2016-04-single-atom-magnet-ground-future-storage.html

    If you have a dynamo, you have a spinning conductor generating a magnetic field but the energy for that comes from the angular momentum of the spinning shaft and if that energy is coupled to a load and you just spin up a shaft with no recurring energy, the shaft slows down and stops eventually because the energy in a magnetic field is drawn off at the expense of the spinning angular momentum.

    In a single atom magnetic field, why does the magnetic field persist?

    What is different about a single atom magnetic field and a magnetic field in a regular generator?
  2. Standard member DeepThought
    Losing the Thread
    15 Apr '16 13:57
    Originally posted by sonhouse
    http://phys.org/news/2016-04-single-atom-magnet-ground-future-storage.html

    If you have a dynamo, you have a spinning conductor generating a magnetic field but the energy for that comes from the angular momentum of the spinning shaft and if that energy is coupled to a load and you just spin up a shaft with no recurring energy, the shaft slows down and sto ...[text shortened]... hat is different about a single atom magnetic field and a magnetic field in a regular generator?
    The magnetic field in a dynamo is, as you said, generated by the rotation (no different to an atom so far). If there were no load, no frictional losses, and no losses due to the resistance of the wires then the magnetic field would persist indefinitely. However, in a real dynamo this is not the case. In an atom there are no losses, the electron cannot lose its spin (although it can be flipped as the article states) and it cannot lose its charge. Consequently the magnetic field the electron generates persists indefinitely.
  3. Standard member sonhouse
    Fast and Curious
    15 Apr '16 16:01 / 1 edit
    Originally posted by DeepThought
    The magnetic field in a dynamo is, as you said, generated by the rotation (no different to an atom so far). If there were no load, no frictional losses, and no losses due to the resistance of the wires then the magnetic field would persist indefinitely. However, in a real dynamo this is not the case. In an atom there are no losses, the electron cannot ...[text shortened]... lose its charge. Consequently the magnetic field the electron generates persists indefinitely.
    Why doesn't it lose energy? I guess because it is basically in a local vacuum and there are no frictional forces to drag down the 'rpm' of the spin? If there IS an RPM If there is, has anyone figured out what that might be?
  4. 15 Apr '16 16:08
    Originally posted by sonhouse
    Why doesn't it lose energy? I guess because it is basically in a local vacuum and there are no frictional forces to drag down the 'rpm' of the spin? If there IS an RPM If there is, has anyone figured out what that might be?
    Magnetic fields do no work.
  5. Standard member sonhouse
    Fast and Curious
    15 Apr '16 16:18
    Originally posted by KazetNagorra
    Magnetic fields do no work.
    True, only fields moving relative to a conductor can do work. I guess the atom field is like superconductivity in a way, nothing dragging energy out of a spin so it just maintains as a permanent magnet.