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Inducing current with magnetic field from light

  1. May 22, 2014 #1
    Hey everybody,

    I was wondering if one could use the magnetic fields of light to induce an electrical current, even if it was just a small one. I'm not talking about the use of photovoltaic cells, but the actual magnetic fields of light.

  2. jcsd
  3. May 22, 2014 #2


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    In accelerating structures, the EM wave in the cavity induces wall currents due to the changing E and B field, depending on the modes/geometry of the field. So having induced current due to EM radiation is rather common.

  4. May 22, 2014 #3


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    Yes, it has been done with light, using high powered ultrafast lasers. The term used in plasma physics is "ponderomotive force"; see http://farside.ph.utexas.edu/teaching/plasma/lectures/node26.html

    Note that the final expressions are in terms of the electric field, but the derivation uses Faraday's law to "convert" the rid the expression of the B field.

    The ponderomotive force is used with high-powered ultrafast lasers to create table-top particle accelerators:

    This was first done about 2004; some of the work was done across the hall from my lab:
  5. May 22, 2014 #4

    Vanadium 50

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    Note that this is exactly what happens in a radio - just with lower frequencies of light.
  6. May 28, 2014 #5
    Thanks for the answers everyone.
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