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Would it be possible to build a model tokamak

  1. Aug 17, 2014 #1
    Would it be possible to just get a swirling plasma in an acrylic tube kind of like the arc reactor in iron man? I'm not talking about anything close to the temperatures or pressures required for fusion just kind of a demo piece to show the general idea.
  2. jcsd
  3. Aug 17, 2014 #2


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    One can buy glass tubes filled with gases, e.g., hydrogen, for electrical discharges, i.e., like fluorescent tubes. One passes a current through the tube at sufficiently high voltage to ionize or excite the gas and obtains an emission spectrum.

    See the lamp demonstrated here -

    One would need to heat the gas to high temperatures to get much of a plasma - a completely dissociated gas in the form of nuclei and free electrons.

    It however would not demonstrate fusion.

    The easiest reactions for fusion are the d+t and d+d reaction. d+t fusion produces a 14.1 MeV neutron, and the d+d reaction generates a 2.45 MeV neutron in about 50% of the reactions, so that requires special protection.

    Building a tokamak is not a trivial undertaking, and is restricted under federal and state laws governing the production of radiation sources.
  4. Aug 17, 2014 #3
    Ya I just wanted to demonstrate how the gasses swirled and the basic concept not generate fusion energy. Also where can you find those laws I tried googling it for a school report a while back and couldn't find anything approaching an official set of rules.
  5. Aug 17, 2014 #4
    We'll other than the basics of no radioactive materials over x amount and refining / possessing u-235/Pu-239 is a big no no
  6. Aug 17, 2014 #5


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    Federal Laws pertaining to radiation and nuclear materials can be found in Chapter 10 of the Code of Federal Regulations (10 CFR).


    Regulation of nuclear materials.

    High voltage devices produce UV and X-ray, in addition to visible light, so there may be state as well as federal regulations. It is one's responsibility to comply with all relevant state and federal laws.
  7. Aug 17, 2014 #6
    Cool thanks
  8. Aug 18, 2014 #7
    What do you mean by "swirled?"

    I think you are interested in building a small apparatus to demonstrate how plasmas respond to magnetic fields and perhaps illustrate some basic concepts related to magnetic confinement.

    You can create a plasma in small cylindrical acrylic tube and use ring magnets to study the response.

    You certainly don't want to build a tokamak. Only the largest tokamaks have discharges that last for seconds. Most smaller experiments have discharges that last only a few milliseconds (if that). Its too short of a time for visual demonstration.
  9. Aug 18, 2014 #8
    Yep that's exactly what I was talking about
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