The Focus Fusion Society Forums Dense Plasma Focus (DPF) Science and Applications Some about a fusion dispute in Sweden.

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  • #402
    Torulf
    Participant

    Excuse me if I wright some thing wrong. English is not my native language.
    I hope you can understand it.
    I’m not sure there to put this. But its contain much about focusfusion so I put it here.

    In 1987 in Sweden we have a intense dispute about the fusion research. It begins in an
    article in a Chemistry periodical news paper. This hapend then I was study chemistry in Gothenburg.
    Sture Hendel and Erik Witalis marked hard critics against tocamak project JET how Sweden
    give money to. Beside of consuming all money they said the tocamak did not work.
    I thought the critic was a little bit hard but I have understand Witalis have done important
    theoretical research in plasma physics. After wards Its obvious Witalis was wrong in some
    details. Many of the problems with instability’s in the tokamak seams to me solved, but i the
    large its still 50 years until the tokamak can deliver energy, same time line as 1987.

    Both Witalis and H

    #2011
    Lerner
    Participant

    The argument about “thermonuclear” neutrons became very arcane. The idea was the reactor could only work if plasma was truly “thermal”, that is near equilibrium, which the plasmoid in the DPF probably never is.

    Supporters of the DPF argued that this was irrelevent. What counted was if the ions and the reaction products were in fact trapped in a dense region–the plasmoid. There is a lot of evidence that they are.

    Bostick joked about that the neutrons had to be “orthodox”–thermal–or the tokamak guys would not count them. The key thing is how much energy you actually produce, not whether you are close to equilibrium or not.

    By the way, you should know about this as a biologist. Organisms that are at equilibrium are dead.

    #2061
    kingkong
    Participant

    I have worked on both plasma focus machine and Tokamak during my graduate study.
    I do not have any doubt that the machine is capable of achieving high temperatures
    sufficient to induce fusion reaction. Even the small machine I have worked with
    produced a lot of fusion neutrons out of a H/D/T plasma. However, I am
    skeptical as to the claim that it could generate power more than it consumes.
    The reasons are well known, and are similar to the problems faced by Tokamaks:

    (a) The loss is proportional to the 4th power of the temperature. This explains the
    huge loss in X-ray Bremmstrahlung. One way to compensate the loss is by making
    the volume large. That explains why LLP needs to build a large machine.

    (b) The problem of ALL fusion machines is NOT ONLY to achieve fusion temperatures.
    That temperature alone has been achieved in Tokamaks since many decades, also
    in the plasma focus machine and Tokamak I have worked with. The main problem
    is to satisfy the Lawson criterion, i.e., that the power output has to be larger than
    the power input, otherwise the device will never work as power generator, but only
    as a power consumer. In this respect the plasma focus machine is inferior to Tokamak,
    because the focus plasma is a very small filament on the order several microns, as
    compared to Tokamaks that has volumes on the magntoude order of LITERS. Until
    LLP can show his overall power balance, I would not give the machine my benefit of
    the dount. While the power produced is proportional to the volume, the main power
    loss (e.g., the radiated power ~T^4) is proprtional to the surafce area. Thus, small
    volumes radiates more than it can produce.

    (c) Is the article “Advances Towards PB11 Fusion with the Dense Plasma Focus” ever
    published in a REFEREED journal? If not, the article is practically worthless. A quick
    scan over its content does not give any hint about the overall power balance, which
    takes account on the overall power output from the fusion plasma VOLUME as
    compared to the input power necessary to generate the fusion temperature. The paper
    seems to be more directed to show that fusion temperature can be achieved. About
    that, I donot have any doubt: plasma focus machines have achieved fusion temperatures
    since at least 30 years ago!

    (d) Also, the article does not take account for many other problems caused by the
    extremely high temperatures and the particles kinetics as well known in Tokamaks.
    For example, how many hours is the lifetime of the machine? Thus, LLP’s plasma focus
    fusion machine is really a very immature concept.

    Can anybody, including Eric Lerner himself, give me satisfactory answer or explanation
    to my doubts?

    😉 😉 😉

    #2063
    Elling
    Participant
    #2068
    kingkong
    Participant

    Aha, by simulation …! Even worse, an extrapolation of simulation results!
    No real experiment or measurement at all ???
    As well known in the art, the result of a simulation fully depends on the skill
    as well as the sense of responsibility of the person who conducts the simulation.
    Therefore my question: is the paper cited above already published in a refereed
    journal? I understand very well, publication in a refereed journal is not a guarantee
    of acceptance or correctness. But if it fails to get published, it really means something,
    i.e., it is incredible. Why? Most probably because it contains a lot of mistakes, either
    mathematical or conceptual, most probably both. As to the sense of responsibility,
    if a person is possessed by greed either for money or for fame, or both, the result
    of his simulation would rather reflect his own wishful thinking, rather than the truth.
    So, the paper you showed me does not lend any credibility at all. Sorry ….
    😉 🙄 :bug:

    #2069
    AaronB
    Participant

    Kingkong, your skepticism is normal. I am skeptical too, and always will be until it actually works. Nobody is claiming that it has produced more energy than it has consumed. The proof of concept will come in the current set of experiments. Simulations are only as good as the assumptions and modeling that go into them. The real test will come after the tests are complete, the correct parameters are determined, and a prototype is constructed. That won’t happen for at least a couple of years. This technology has been around for a long time, as you are well aware, and there is a lot of work still to do. That is the way science and technology progresses. If you are interested in the paper being peer reviewed, and you are experienced in the field and with an actual device, why don’t you review it for us?
    One thing to remember is the importance of ratios. We know that a lot of power must be pumped into the device. The key is to get a higher ratio of the energy converted into the formation, compression, and heating of the plasmoid. Then there must be a low proportion of energy given off by wasted radiation. Then there must be a high ratio of energy captured from the final products. Each of these important elements are being tested now. The formation of the plasmoid will hopefully be improved by the injected angular momentum, the radiation lessened by the magnetic field effect, and the conversion into usable energy by the x-ray capture device and the coil. If the ratio of typical losses in each of these steps can be reduced enough, then the combined ratios will leave us with net positive energy. That is the goal. Now that you hopefully understand the process, which part would you like to help us improve upon?

    #2070
    ptrubey
    Participant

    What is the x-ray capture device?

    #2071
    Elling
    Participant

    Still, if the reactor produces 5MW per 4MW input, it’s not instaneously obvious that it’s commercially attractive.
    4MW is a big chunk of power that can’t be sunk everywhere without a sufficient grid.
    The reactor would be just anotherbid in the continuing “competition” between other energy sources.
    The power conditioning around the site is trivial allright but expensive and bulky.
    I think a Q = 5 or 10 is necessary to revolutionize the buisness.

    #2072
    Jolly Roger
    Participant

    ptrubey wrote: What is the x-ray capture device?

    There is a brief mention of the x-ray/electricity converter in this article on the main Focus Fusion site.

    https://focusfusion.org/index.php/site/article/lpp_submits_patent_application/

    I assume that it has not yet been perfected and that much research will be needed to find the right (best) materials.

    #2073
    Glenn Millam
    Participant

    Lerner wrote: The key thing is how much energy you actually produce, not whether you are close to equilibrium or not.

    And this says a lot about the difference in attitude between big tokamak-based projects and FF. From what I have read, its sounds a lot more like those projects are more interested in controlled scientific discovery and research than they are about creating a power source. As far as I am concerned, if we were getting large amounts of net energy from FF because tiny 10-dimensional space monkeys were found to be dancing inside the plasmoids and making the p-boron fuse, then go, monkey, go!

    #2074
    Jolly Roger
    Participant

    Glenn Millam wrote: As far as I am concerned, if we were getting large amounts of net energy from FF because tiny 10-dimensional space monkeys were found to be dancing inside the plasmoids and making the p-boron fuse, then go, monkey, go!

    Glenn,

    Would those space monkeys be related to the critter Wm. Shatner shot off an airplane wing in “Twilight Zone”? 😉

    But seriously, I agree. Let’s get the gizmo working. Take lots of notes and figure out the particulars later.

    #2096
    Frenetic
    Participant

    Look at it this way. A bet placed on Focus Fusion or a derivative of the Farnsworth Fusor is a much better bet than money put down on a Tokamak. Why? Because if you assume that all three have about an equal chance of producing substantial quantities of power, the bets on Focus and Farnsworth are one whole hell of a lot cheaper the money required to construct any magnetic containment device. Most of the fusion reactor designs I have looked at are, well, ridiculous. It’s like we designed a stove that needs a flamethrower for a pilot light. I have a sneaking hunch that anything workable that comes out ITER will need its very on fission plant for start-up and standby.

    My own personal inclination is to say that this design (Focus) and one of the Farnsworth derivatives are both far more likely to work than any of the other designs I have examined and I think I have looked at all the serious ones described on the web. There may be a secret one somewhere that I don’t know about, but all bets are off on those.

    #2353
    mchargue
    Participant

    Glenn Millam wrote:

    The key thing is how much energy you actually produce, not whether you are close to equilibrium or not.

    And this says a lot about the difference in attitude between big tokamak-based projects and FF. From what I have read, its sounds a lot more like those projects are more interested in controlled scientific discovery and research than they are about creating a power source. As far as I am concerned, if we were getting large amounts of net energy from FF because tiny 10-dimensional space monkeys were found to be dancing inside the plasmoids and making the p-boron fuse, then go, monkey, go!

    Well stated.

    (Go monkeys!)

    #2361
    Transmute
    Participant

    As long as its energy positive and cheap, this is where tokamak fails (ungodly expensive). If DPF fusion only manages a source-to-gird net energy of 110% its will still be worth its as long as its producing a few megawatts per cheap reactor. Tokamak is predicted to be producing 1MW per $25 million in its construction and research, coal power plants is at $1.3 million per MW (not include the price of coal) and if its works as claimed DPF could do $.2 million or less per MW! but yes monkeys could help.

    #2568
    Brian H
    Participant

    Transmute wrote: As long as its energy positive and cheap, this is where tokamak fails (ungodly expensive). If DPF fusion only manages a source-to-gird net energy of 110% its will still be worth its as long as its producing a few megawatts per cheap reactor. Tokamak is predicted to be producing 1MW per $25 million in its construction and research, coal power plants is at $1.3 million per MW (not include the price of coal) and if its works as claimed DPF could do $.2 million or less per MW! but yes monkeys could help.

    In imagistic terms, it seems to me what FF has achieved is the exploitation of a discontinuity, or tipping point, such that a tiny amount of the right stuff is induced to self-constrict into a tiny volume with exponentially escalating pressure and temperature. The “break” that stops the process is the absorption of the hydrogen and breakup of the C12, which transforms the magnetic and temperature energies into a kinetic jet of H3. Which is easily “bled” of its power in a solenoid. The “bigger boxes”, like ITER, are playing on scales where there is no mechanism for self-containment, and no way to keep the reacting elements in contact long enough. Gravity works on large, stellar scales, and “pinch” magnetic effects on the FF scale, but in between is pure energy sink wasteland.

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