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Accelerating current

  1. Dec 18, 2011 #1
    Current is simply flow of charge,
    and acceleration of charged particles produces EM radiation.
    Then if we bend a wire,charges(current) would be accelerated as they change direction,then a bent wire must radiate.Is it true?
  2. jcsd
  3. Dec 18, 2011 #2


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    Science Advisor

    Radiation is produced by a changing current, or a changing charge distribution. A steady current does not produce radiation, even in a circular wire.
  4. Dec 18, 2011 #3
    When charged particles, electrons, protons etc, are travelling in circular paths in accelerators they produce radiation sometimes know as synchrotron radiation.
    Some synchrotrons are used as sources of X-rays.
  5. Dec 19, 2011 #4
    But then even steady current moving in curved path is same as electrons moving in synchrotons.the electrons do radiate so why doesn't the current(which is simply flow of electrons)?

    I am totally confused here?????
  6. Dec 19, 2011 #5

    king vitamin

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    A steady current in a circular wire has a constant charge density throughout. Maxwell's equations gives zero/constant electric field (if the wire is approx. zero charge or charged) and constant magnetic field - no radiation. An electron in a cyclotron does NOT have a constant charge density so the electric field is time dependent. For that matter the magnetic field would be more complicated too!

    The way I understood the first post I imagined bending a wire as charge was flowing through it - in this case there would be radiation of course, since the magnetic field would change.
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