Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Fusion possible with high voltage on deuterium?

  1. Jul 19, 2006 #1
    You hear from me first. I claim, “We can apply very high voltage on deuterium to achieve fusion power generation.” Using a device like a van De Graaff or Tesla Coils machine, we can generate very high voltage with minimum power input on a deuterium gas mixture which surrounds a pullet. The sudden heat generated from the natural lightning like reaction will cause further head through sudden compression. The inertia of the imploding atoms in the gas forces the pellet to be compressed in a very short time and causes fusion burn. The input power is basically ignorable comparing to the power output from the fusion effect. Unfortunately, I don’t have resources to support my claim. However, I believe it works.
  2. jcsd
  3. Jul 19, 2006 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    Then how does one know it works? Believing something works doesn't cut it here.

    One claims, "The input power is basically ignorable comparing to the power output from the fusion effect" - but on what basis? One could certainly perform an analysis with the appropriate analytical models and methods to explore the energy produced by the 'natural lightning', the compression of the DD - gas/pellet, and the energy produced in fusion.

    I believe this concept has been tried and it was unsuccessful. This sounds very similar to the Fusor concept - http://en.wikipedia.org/wiki/Fusor.
  4. Jul 19, 2006 #3


    User Avatar
    Gold Member

    It has been tried, around 1934 in Sweden or perhaps Copenhagen. The Deuterium was loaded into Paladium or Platinum wires, I do not remember well, and then a high current was applied. The results were said to be negative.

    During the "cold fusion" fever the experience was repeated, or at least someone suggested to repeat it.
    Last edited: Jul 19, 2006
  5. Jul 19, 2006 #4
    Thanks for both responses. First, I agree 'believing' does not mean anything, but it is a driving force for science experiments. Second, electrical current is not equivalent to electrical voltage. Third, the Fusor Fusion is similar to what I claimed, but not quite. Using a van De Graaff machine, we can easily achieve over 10 million eV. After researching past experiements, I did not find anything saying using very (very) high voltage on deuterium gas mixture surrounding a pullet. If anyone do, please let me know.

    Thanks very much in advance.
  6. Jul 20, 2006 #5


    User Avatar
    Staff Emeritus
    Science Advisor

    Certainly current is not voltage. However, there is usually a voltage associated with a current - a voltage (EMF) produces the current.

    In the case of lightning, something, the deuterium pellet for instance, would need to be grounded so that the 'lighting bolt' would be directed to it.

    As for using a Van de Graff machine, one could get 15-20 MeV per device, and one could use a Tandem VdG (http://www.bnl.gov/bnlweb/facilities/TVdG.asp [Broken]) to double the energy. On the other hand, one must consider the beam current. VdG's are large machines by the way.

    Then it is a matter of applying the current to the surface of the pellet (in 3D) with a relatively high degree of symmetry, otherwise an asymmetric energy deposition would simply 'vaporize' the deuterium pellet.
    Last edited by a moderator: May 2, 2017
  7. Jul 20, 2006 #6
    Agree. That is why in my rough design I will use a ballon to contain the pellet with deuterium gas mixture surrounding the pellet. I am not considering applying the high eV on the pellet directly, but on the surrounding gas mixture. The lightning bolt does not have to be direct to the ground. Instead, the negative charge will be directly to the surfact of the ballon with positive charge coming from a thin wire jumping to the ballon, causing a discharge. This then reacts on the gas mixture which heats up and reacts. The resulting pressure will in turn causing inertia compression on the pellet.
  8. Jul 20, 2006 #7


    User Avatar
    Staff Emeritus
    Science Advisor

    I doubt it. There would not be sufficient momentum generated in the gas to compress the pellet. That is why inertial confinement is proposed.

    The lightning bolt would be assymetrical and as such the D gas could be compressed in one direction and expand in another, and thus an insignificant compression wave would interact on the pellet.
  9. Jul 20, 2006 #8
    That is exactly the spirit of science. However, we cannot rule out the possibility. After all, we need facts and figures to prove that very high eV will not induce fusion, and vice versa.
  10. Jul 21, 2006 #9


    User Avatar
    Staff Emeritus
    Science Advisor

    Well, one can check the cross-section data to see that fusion requires energies in the keV range, e.g. ~70-100 keV for DT fusion assuming a Maxwellian distribution, and somewhat greater for other reactions, in order to produce substantial energies in excess of input energy. In the case of a beam on a low energy target, the energies are much higher. Of course, one can produce a neutron source by the fusion process with energies in the low keV range - this is the principle of the neutron howitzer.

    One could certainly model the physics of a D-gas heated by a lightning discharge and then model the plasma dynamics, assuming one knows the appropriate boundary conditions, the plasma dynamics, and the appropriate equations of state (constitutive equations).
    Last edited: Jul 21, 2006
  11. Jul 21, 2006 #10
    As said, designing such a reactor is not easy. However, it may be worthwhile since existing fusion experiments do not produce commercially satisfactory result. Also, let us examine the facts:
    1. Fusion does occur in some natural lightning, but not all the time. In fact, it is no miracle that why some people survive from lightning stroke. High eV itself does not produce high energy, nor is height the only factor in natural lightning. Check out the data of some inner cloud or cloud-to-cloud lightning.
    2. Try a simple experiment yourself using propane, mixing with D-gas. You will see what happens.
    3. If this design works, it is an econormical way to produce energy (especially the price at the pump is getting higher each day).

    Thanks again to Astronuc for his feedback.
  12. Jul 21, 2006 #11
  13. Jul 21, 2006 #12


    User Avatar
    Staff Emeritus
    Science Advisor

    I don't believe that is correct. What nuclei would fuse in lightning - which is mostly heated and highly ionized nitrogen and oxygen atoms.

    It is the high electric current that kills, and some people do miraculously survive a lightning strike.

    Edit: Lightning potentials can be several MV, and perhaps up to 100 MV, with large currents 10's - 100's kA. (See below)

    Zip. I'll guarantee that one will not be getting much, if any fusion, with that mixture.
    Last edited: Jul 22, 2006
  14. Jul 21, 2006 #13
    Please don't forget deuterium does exist in nature. Also, exactly as said, it is high current that kills. Will high current occur in all natural lightning? I guess not. BTW, I will not give guarantee on anything until I have facts and figures.
  15. Jul 21, 2006 #14
    BTW, I say, I claim, I believe, but I will not guarantee. An apple will fall to the ground 99.9 % of the time, but....
  16. Jul 21, 2006 #15


    User Avatar
    Staff Emeritus
    Science Advisor

    True, but only a very small amount in water, and water vapor is a small amount in the air.

    The atomic/molecular density of deuterium is so small and insignificant as to preclude any fusion due to lightning.

    As for lightning -

    Lightning - http://thunder.msfc.nasa.gov/primer/primer2.html [Broken]

    Potential difference - on order of 1 MV.

    Temperature in lightning current (bolt) - ~20000K = 1.7 eV

    The length and duration of each lightning stroke vary, but typically average about 30 microseconds. (The average peak power per stroke is about 1012 watts.)

    But - http://thunder.msfc.nasa.gov/primer/primer3.html [Broken]
    states that "an electrical potential difference of 200 to 500 kV exists between the Earth's surface and the ionosphere, with a fair weather current of about 2x10-12 amperes/meter2. It is widely believed that this potential difference is due to the world-wide distribution of thunderstorms."

    ANL - Ask A Scientist© - cites encyclopedia Britannica

    http://apollo.lsc.vsc.edu/classes/met130/notes/chapter15/charge_distribution.html1 [Broken]
    Voltage of a Lightning Bolt - 10 MV to ~100 MV.
    Last edited by a moderator: May 2, 2017
  17. Jul 24, 2006 #16
    Perhaps the title should be changed to 'Access possible if ISP not down' :-).
    1. The peak power in natural lightning can go higher than 400kA, or as low as 10kA. High eV alone will not generate that. Check van De Graff machine. The temperature in nautral lightning is between 20000K to 30000K. Also, energy may not be near its peak during dart lead.
    2. Fusion in the sun is a catalyzed cycle. It goes from ordinary hydrogen, to an atom of C-12, creating N-13, becomes C-13, then N-14, O-15, decays to N-15, N-15 plus another proton yields C-12 plus a He-4 nucleus.
    3. Propane is chemical compound of carbon and hydrogen, and is heavier than air (CH3CH2CH3C3H8). It will not burn completely in the air. With very high eV applied and D-gas as the gas catalyst, propane will burn almost completely. BTW, I did not say fusion could occur.
  18. Jul 24, 2006 #17
    Most power-generating schemes based on accelerating ions are impractical. Look at the numbers; you need to supply on the order of 50keV to each nucleus you want to fuse (D-T), and even then there's only a tiny probability that you will actually get fusion to release the 17MeV of the D-T reaction. So to get net power output from acceleration, you must have a system with at least one fusion for every ~400 nuclei accelerated. This is nowhere near achievable - thermodynamically, the high-energy nuclei will scatter far more often than fuse, and lose their energy to heating up colder ions. Essentially any scheme based on acceleration has this probolem; most of the energy goes into heating by collisions, and you're many orders of magnitude short from power output.

    The essential point here is that there's a huge temperature difference - 50keV ions in a 25-50meV thermal environment. Heating losses can be much less significant if the whole environment is at the same 50keV temperature - that's the principle of "hot" fusion such as magnetic-confinement fusion; the whole plasma is heated up, and thermal losses are limited to those from collisions with the walls of the container, which the magnetic field tries to minimize (there are more important losses in these systems.) Inertial-confinement fusion would do the same thing; lasers suddenly heat up a large region of a solid pellet, and the inertia of the surround pellet keeps it together for long enough for fusion (sort of like a nuclear bomb).

    It's a basic principle; "hot" fusion gets net power output, "cold" fusion doesn't.

    There was a chapter of a rather old nuclear physics book I looked at once, where he discussed this at length and did some very insightful OOM estimation, with cross sections and Maxwell distributions and such, to get upper-bounds on energy output from "cold" fusion processes like accelerating ions at a target. Unfortunately I don't remember who it was - maybe Astronuc knows?
    Last edited by a moderator: Jul 24, 2006
  19. Jul 25, 2006 #18

    As you may imagine, physicist have accumalted data on the fusion reaction by producing it in a laboratory.

    One of the possible ways is indeed by accelerating some beam and fire it on a target. You typically need a high voltage source of maybe 20 kV, not much more that in you old TV set. One example of such an fusion device is the duoplasmatron. It is not that complicated if you own some D and some T !!!

    Another example is simply the neutral beam injection firing on a tokamak plasma: D ions can be accelerated and then neutralized to allow them to penetrate deeply in a hot magnetised plasma. When interacting with the plasma, two main things can happen: plasma heating and fusion reaction. The fusion neutron obtained in this way have been observed on many tokamak and are used as a diagnostic. If heating is sufficient it may also produce -indirectly- the fusion reaction. This last scenario is the main goal of fusion research. (see http://www.jet.efda.org/)

    The problem to produce fusion power in not to produce fusion but it is to ignite the plasma (or the pellet for inertial fusion). This means that the fusion reaction itself should be able to trigger other fusion reactions and hopefully produce more energy than needed for ignition.

    Last edited: Jul 25, 2006
  20. Jul 25, 2006 #19
    First, I would like to thank all who contributed. My intention here is not to invent a new theory, but to look at existing methods differently. The existing methods have been trying to get fusion burn continuously. Could we possibly obtain energy through natural lightning like fusion reaction? Are there any other ways we can achieve fusion commercially possible instead of trying to heat it up higher and higher?

    Cross my fingers, I am waiting for an answer ASAP.
  21. Nov 13, 2009 #20
    Just discovered this great forum. Am interested in the math behind fusion, particularly beam-target fusion.

    Does anyone happen to know where this calculation comes from, that to get net power from an accelerated beam system you need at least one fusion for every ~400 nuclei accelerated?

    Also, does anyone know the title of the nuclear physics book mentioned with insightful OOM estimation, with cross sections and Maxwell distributions and such, to get upper-bounds on energy output from "cold" fusion processes like accelerating ions at a target? Thanks greatly. --ds

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook