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Can magnet fields deflect displacement currents?

  1. Jan 4, 2012 #1
    Can magnet fields deflect displacement currents?

    Could displacement currents be made to propagate in spirals like those in a cyclotron?

    Do they travel close to the speed of light?

    Can they be focused into beams?

    Can they transmit electrical energy at a distance?

    Are they subject to the same friction as electrons?

    Can they be used to charge capacitors from outside a circuit?

    Are there any significant applications of displacement current at present? If not, then why is that?
  2. jcsd
  3. Jan 4, 2012 #2
    The displacement current has units of current but there is no physical charge present.

    Magnetic fields do not exert forces on one another or magnetics would be a nonlinear phenomenon.

    In short, magnetic fields exert forces on moving charges, not on other magnetic fields.
  4. Jan 4, 2012 #3
  5. Jan 4, 2012 #4
    Are you saying that the concept of nonlinear magnetic phenomenon is outside of science? Just in what sense do you mean by "nonlinear phenomenon"?
  6. Jan 4, 2012 #5
    Are you saying that magnetic fields can only interact with an electric field if the divergence of the electric field is non-zero?

    Are you suggesting that there is type of changing electric field that the magnetic field cannot interact with?

    Why say this when whether or not something is purely electric, purely magnetic, or somewhere in between depends on the reference frame of the observer?
    Last edited: Jan 4, 2012
  7. Jan 4, 2012 #6


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    "Can magnet fields deflect displacement currents?"
    Yes. If a magnetic field passed between the plates of a charging capacitor.
    the EM momentum given by DXB would change. This would be balanced by a torque on the capacitor. The torque would be the same as for a current I=dD/dt.
    (I have left out extraneous factors.)
  8. Jan 6, 2012 #7
    Clem, this is not correct. The displacement currents do create magnetic fields. But they cannot be deflected by magnetic fields because they are not moving charges.

    If they could then you could deflect a beam of light with a magnet. But you can't.
  9. Jan 7, 2012 #8
    But light doesn't have a net displacement current. I mean, it alternates between positive and negative, does it not? So that's not something that would be easy to observe, right?

    But guess what, it turns out there are several effects out there where light can interact with magnetic fields. See:



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