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Easy, cheap, EM propulsion

  1. Mar 2, 2005 #1


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    Any ideas for an easy cheap EM propulsion device? Is a homopolar generator the same thing as a homopolar motor?
  2. jcsd
  3. Mar 2, 2005 #2
    use the momentum of a photon to propell yourself. Thats the great thing about photons, they have no rest mass but they do have momentum. The problem is that the momentum is not great enough to achieve great accelerations.


  4. Mar 3, 2005 #3


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    I was thinking more along the lines of electricity and magnetism. I don't know if you were serious or not with that, photon acceleration, but I want something EASY and CHEAP, that I can do without contacting a major laboratory.

    -Thanks, Mk
  5. Mar 3, 2005 #4
    Mk, photon momentum i.e. radiation pressure is a result of the electromagnetic field (rather than a particle) carrying energy. This is how a solar sail works. It doesn't get any more electromagnetic than photons.

    A homopolar generator is the reverse of a homopolar motor. As a generator, it converts mechanical work to electrical current, and as a motor it converts electrical current to mechanical energy (the same relationship applies to any basic motor-generator combo).

    Rail guns are an excellent electromagnetic propulsion device. The physics of how they operate is semi-complex, so I will refer you to google. Regardless, rail guns are only practical for accelerating highly rigid objects.
  6. Mar 3, 2005 #5


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    Well, I know the photon is as electromagnetic-related as you can get, but I was thinking more along the lines of homopolar motors, rail guns, coil guns, and such.

    -Thanks, Mk
  7. Mar 3, 2005 #6


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    If I made a copper wire coil around a metal tube, and a circular cuttout of a copper sheet, with a hole in the middle, slipped the coil-tube combo through the hole, and ran electricity through the middle coil, would that function as a Thompson's Coil? Or does it take more?
    Last edited: Mar 3, 2005
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