Fusor Forums

I have faith in many things, hunches about others, strong feelings that transcend science, but none of these feed th' bull dog.

I really believe that fusion will be mastered; just not by any method in use or dreamed of at the current moment in time.

Fission uses real potential energy in virtually the same way as burning a log. Fusion has none of these attributes. That is why fission was an instant success and a no brainer.

As regards the idea of the chain reaction being the tipping point for fission.......The idea came only months after the discovery of fission, itself, and the first net energy producing pile only 3 years later. No great, unseen, leap here. The meanest intelligence would have seen the chain reaction following the fission discovery in short order. Szilard was no lucky donkey here he just saw the obvious a bit faster than others.

Fusion languishes, yet, lo these many years later, lost and adrift. Fusion has no need of a modern day Szilard. It needs a true, lucky donkey and a new spin on fusion physics, itself.

Fission has produced terawatts on grid to you and me for the past 50 years and stands ready to continue to do it on into a distant future.

Fusion remains a very distant article of faith.

Richard Hull

Richard,

I've been pondering this for a while and determined that the issue at hand is entropy. It is not a mater of whether the potential energy is real or not, it is clearly and measurably real. The issue at hand is whether or not the process would happen on it's own regardless of conditions.

Water will continue it's fall,
Wood or coal will eventually oxidize, even without flame,
Fissile isotopes will split according to their respective half lives,
Portions of the earth's crust will warm and cool just as they have for ages past.

Man has proven adept at harnessing energy that is already well on it's entropic path to meet his needs and has found ways of accelerating certain entropic systems to make them truly useful.


Deuterium on the other hand will remain deuterium age after age. Entropy does not play here. There is no natural process at work outside of the stars themselves. There is certainly nothing that can conveniently be throttled up to a useful state.


For my part I simply see fusion as the next step. In the past man has progressed through being passively affected by energy through influencing to harnessing energy already in motion. To succeed at fusion man will finally have to actively instigate the process instead of simply being a lucky beneficiary.

It won't be easy, but the opportunity is tremendous.

The "virtual potential energy" was not meant to be a scientific term put forward by me, but more of in the vein in which Trent spoke. There is no way to release the potential energy and have it continue to burn. Deuterium is not a fuel in the classic sense.

Special if not ideal and precise conditions must be established to bring the energy forth. The energy is not a nascent potential energy in what we call the fuel, but a promised energy based on special conditions involving the fuel that are completely non-trivial and even go beyond an economically reasonable pale based on any other energy source where the energy is locked in and more than up to being released by relatively simple means.

With the volumetric efficiency of the sun, fusion looks bad. We would have to beat the sun at its own game.

As always in fission or fusion where mass is increased or decreased in the reaction, no charged matter particles are created or destroyed. The vaporous, non descript, "mass defect" is all that comes or goes in the E=mc^2 equation. A will-o-the-wisp that comes and goes to make the equations happy and work OK.

Richard Hull

Mr. Hull

Thanks for another fine philosophical physics thread, you all should get together and write a 'Nuclear Physic for Dummies' book (probably already out there); I think your musings are along the lines of Isaac Asimov's writings (trying to be complementary) and you could paint informative works for the public.

I am trying to 'search' the forums for some basic fusion reaction energy requirements.
Haven't found it yet, might have read right through it. Found the 'Lawson Criterion' and 'Fusion Energy Gain Factor' discussions on Wikipedia, however they are a bit abstract for me, not having great advance math skills.

If I take an 'ideal' energy reflective container, add four deuterium nuclei to it and just enough energy to get two of the nuclei to fuse yielding one He3 and that wonderful 'mass defect' stuff, is the extra exothermic 2.45 Mev enough to activate the remaining two D nuclei to fuse. I see the equations in the Farnsworth patent 3,386,883, but don't see the input energys required. I ask this naive question because you discuss 'virtual potential energy' that appears to be only extractable in the fire of a fission reaction to sustain the fusion output. This makes me think that there isn't enough resultant energy to keep man made fusion plus containment going in any form outside of a gravitation bottle. I'll look some more.

Thanks.

Chris,

I'm not so sure that your statement is accurate. While you are right that deuterium is very stable "age after age". There is plenty of evidence that there is spontaneous deuterium fusion everywhere that deuterium has a presence. It is a question of reaction rate and how favorable the conditions are.

For instance, there is no sharp cutoff within fusors for the reaction. The reaction does become very low below ~10k volts though. High voltage gradients are very common everywhere on the surface of the earth. (Just take off your sweater in a dark room and dry climate sometime.) If you delve into very small environments, high voltages are even more common and less apparent.

There is evidence that spontaneous transmutation occurs perhaps even at all times everywhere at a very low rate. My intuition (perhaps flawed) is that we are achieving measurable fusion because we are subjecting elements which by their nature spontaneously transmute, to an elevated level of energy which increases the rate but does not cause the transmutation. My guess is that the conditions exist for deuterium transmutations throughout the range of stable existence of D and it's transmutation products except perhaps at absolute zero and maybe at the very top.

With regard to Richard's idea

<Real potential energy. (PE) is extant if at some
< time in the past, for any reason, energy has
<been input to a system and stored there.

This is obviously true and evident on the face of it when you hear it spoken. It is also indisputably practical. However there is an unspoken both practical and philosophical suggestion contained here that I just can't accept. The suggestion is that it happened in the past and is not happening significantly now.

I think that this must be wrong. I have no practical evidence. However it doesn't make logical sense. The knowledge that anything exists at all is proof that mass is not dissipating overall and that the entire edifice known as the second law of thermodynamics is flawed in a basic but unknown way. This, of course, isn't practical because for practical purposes mass (energy) does dissipate insofar as we as consumers of energy are concerned. We will eventually dissipate. It's hard to argue with that.

But hope springs eternal. I think the fusion nut will be cracked. I don't think it will involve a self sustaining burn, and I also would be delighted if it would lead to a different understanding of thermodynamics (but it probably will not).

Don

That's the problem with speaking in generalities, or making conceptual arguments, someone can always point out a technical flaw.


I am of course aware that even at STP, maxwellian distribution will result in a few deuterons reaching fusionable potential. I am also aware of the impressive potentials that can be accomplished easily on a microscopic scale. This would seem to translate into the reality that fusion happens all around us, all the time. Unfortunately these fusion events seem so vanishingly rare as to be for most instances and purposes unmeasurable, irreproducible, and nonexistent.

I would dearly love for someone to point out a common earthbound natural fusion process for us to study; unfortunately as far as I know our only natural example of an ongoing fusion process is, and still remains, purely celestial.

Fusion is tough because, even with somewhat ideal conditions, it is probablistic based on cross sections of the fuel nuclei. The thinner the fuel density, the lower the probabilty that any significant fraction of your seed energy will be returned much less create a net energy outpouring.

This entire fusion scenario is nature's way of not having the protium in the universe go up like a tender box. Fusion is deliberately intended to be a volumetrically rotten source of energy, even at the stellar level!

The Lawson criteria tells the story of how fusion is the only game in town, on a universal level, and that you can't win, because the game is rigged. Yes, there is always a winner in the fusion lottery based on probability, but the losers abound, ad infinitum.

The answer to another question....Is there enough energy in fusion (d-d), given an ideal reflector to create another fusion ala chain reaction? Yes there is, many times over, ideally, and the idealists call it "ignition" in the fusion camp. Alas, there are no ideal reflectors and nature doesn't like ignition save in stars, where the Lawson criteria keeps the ignition temperature limited and unbridled fusion in check. (Thank Goodness!)

Richard Hull

Many men died in the cold before the mystery of fire was harnessed.

Heisenberg's Uncertainty will be chipped away, reshaped, maybe discarded. The super cold and the super hot will be studied at length. Better tools fashioned, providing added information to the ambient constructs. How accurately we interpret the "Qaunta Bones" reveals our understanding of what is real and sets the time scale for progress.

Mass into energy, energy into mass. Hot into cold, cold into hot. Opposite sides of mysterious coin that remains half understood, hence half spent at our hand.

Someday we may learn to stack and unstack the Qaunta bones as we see fit, provided we don’t perish in the cold with no understanding of fire….

C.

I could tell by your previous posts that nothing I wrote above would be a surprise or new to you. You're much more familiar with this material than I am by a good long shot.

I agree about the generalities idea. I just wish I had more free time and resources to pursue the more particular side of this business.

Don