Quantum world views - It's what make fusion happen

It may be difficult to separate "theory" from "application," but let''s see if this helps facilitate the discussion.
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Richard Hull
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Quantum world views - It's what make fusion happen

Post by Richard Hull »

Is it important to know and understand Quantum physics to do fusion?...Absolutely not! It is important, however, to have a rudimentary understanding of its principles. We need to understand how "Quantum uncertainty", and in our case, "Quantum tunneling" aids us and yet limits energy producing fusion. These quantized functions have an iron grip on the fusion process in the world of the small.

We all have to accept that fusion, at our level of performance or perhaps at any level, is due to quantum level interactions and uncertainties, which at the core, are 100% probabilistic in a quirky and very spooky way. When all the smoke clears, we are rolling the dice in a quantum world and hoping for a real world result of some benefit, (creating useful energy).

It is painfully obvious that we are not having one round solid ball deuteron impact flawlessly, head-on, with another deuteron at some energy "X" that is well known to create fusion. We know that is not true and will never happen. Even such idealistic head-on collisions in a hail of particles, would turn back into a probability solution, but at least a totally predictable, non-spooky fashion.

The real research at the real world level shows that direct hits, even at full fusion energy, may not result in a fusion. Full fusion energy is usually about where fission, or in our case, D-D "stripping" via the Oppenheimer-Philips reaction occurs. We do fusion at such a low energy level that we are forced to rely totally on "Quantum tunneling". Fusion, for us, is totally probabilistic, but at a rather spooky quantum level which we can't control, but can direct in a real world fashion by creating a super complicated, many body, energetic environment which, due to its quantum nature, does fusion.

Quantum theory, in our case, is not of single, joined or bound system of particles at room temperature where total stability reigns, as in a kernel of corn. We work in a "densified" group of totally unbound, yet somewhat confined, recirculating, energetic single entities of the same charge that do not want to come together! Fusion, be it thermal plasma heating or electrostatically confined fusible fuel, will remain a losing crap shoot with "containment" of the complex single particle, electrostatically repellent assemblage! The weakness of all fusion systems is due to quantum uncertainty or Quantum tunneling, in our case.

Containment of the repelling particles at usable fusion energies and density is the ultimate problem in doing useful fusion. This issue is yet to be solved, as all such grossly imbalanced, energetic systems seek to find their lowest energy state. (cool down or leak away into an unbound state)

Fusion "cross sections" are a symbol of, and the ultimate limiting factor in fusion. These cross sections are all based on observed quantum fusion probabilities at varying energies of two body, "tunneling" collisions among many particles. Fusion can even occur with a non-contact very close pass-by or approach.

Quantum theory is, itself, a usable model, only, and not a fixed edifice as is discussed at some length in this article in Scientific American.

https://www.scientificamerican.com/arti ... ket-newtab

Enjoy straining your brain a bit. Newbies without the chops to follow might find all this a bit confusing. You will see even the mighty are out there thinking. As they learn or believe they have learned, they then tell us what to think in the classroom. Fail at understanding and you will not make the grade. College "pass-men" are just that.... pass-men, like me, who are there to be hired in better jobs than the rest of the herd. The best part of college was to be teaching you to think, question and know how to ferret out data to help you think deeper and better. Once out of college, it is to work and family, buying a home, paying bills and only old farts like me, in retirement, dare try to think deeply again. But alas, it is often too late and a vanity to take to the grave.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Dennis P Brown
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Re: Quantum world views - It's what make fusion happen

Post by Dennis P Brown »

Excellent overview of the fusor process. Certainly, not a process that has any real analogy in the real world so can be a bit weird for most people to accept.

As for us older folks continuing to think (education), that is also one of the best ways to keep the mind sharp. Your continued and improved experiments in fusor induced activation are both impressive and inspiring; that too keeps one sharp, as well.

Scientific American (and started my subscription, finally, again) is still the best general science magazine for people of a scientific bend who can handle more than the average level.

And with google, little excuse for anyone to not figure out how to cross check and learn rather than accept what their too often believed to be 'betters' on the internet tend to post with no proof. All one has to do is maintain an open mind, and do some simple research (i.e. invest a tiny bit of intellectual effort rather than accept these pronouncements - even if it supports one's world view.) But hey, stay off my lawn ...oops, freudian slip ;) .
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Nicolas Krause
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Re: Quantum world views - It's what make fusion happen

Post by Nicolas Krause »

Can anyone suggest some good resources for learning about fusion and the nucleus? I'm currently reading Models of the Atomic Nucleus by Norman D. Cook, which is a nice overview of the different approaches, liquid drop, shell etc.. I have a good sense of what to search for when I want to learn some math, but with Physics I don't seem to have as much luck.
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Re: Quantum world views - It's what make fusion happen

Post by Dennis P Brown »

Most "Modern Physics" text books cover the nculeus in a more realistic manner. You can skip the Special Rel. in these books, of course.
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Re: Quantum world views - It's what make fusion happen

Post by Nicolas Krause »

Thanks Dennis, I'll take a look at a few of those. Does anyone have any experience with lattice models of the nucleus? I know the standard/older models are liquid drop and shell types, but I'm curious if anyone has investigated the idea that there's an ordered structure to the nucleus and its potential impact on fusion.
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Re: Quantum world views - It's what make fusion happen

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Nicolas, You are digging in as only our ideal poster might. The question you ask here is one for the ages. When digging this deep into nuclear physics, things get very murky. Science is and has been just guessing on this topic for years. We invented the strong and weak nuclear forces, and many other things upon which we say, "We can't see it but it must be real", concepts over the years. We even have mathematical reductions of precisely what these inter- nuclear forces must be and how they must interact. All of this is part of the standard model. It has ranged far and deep into a black abyss where great guesses are made, with suitable mathematics to bolster the concepts posited. Everything seems to work mathematically. It is a "best fit". It has to fit or we dare not call it science. The quantum limit has not stopped the musing and searching.

Take all you read with a grain of salt regarding a nuclear "nucleus model". We seem to have done it to a working level with the electron shell model, extra-nuclear. The important thing to realize is we will never have what we feel is a reality in the normal sense of a ponderable, physical reality, once you touch the "quantum barrier".

The quantum barrier exists, like it or not, just below the molecular level of solid reality. I was once enthralled with the shell model where the nucleus was envisioned to be a assemblage of helium nuclei. But that was before I realized reality is hazy at that level. It is natural to seek some form of useful, model of the nucleus. Unfortunately, no fixed model exists that is mathematically satisfying in every test.

Enjoy your quest for a nuclear model of the nucleus. Just remember the quantum limit of reality is always there it is the human "dogs" rope limit. It is as far as our examination of reality of space, time and matter can be extended. The mind of man can push the limit built upon theory, experiment and mathematics, but the reality just doesn't exist for us. At what levels of time, space, and matter leaves predictable, ponderable reality is another question for the ages. Way back, time was the chronon, 10e-24 sec. .... The time light took to cross the diameter,(if such a thing exists), of the electron.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Quantum world views - It's what make fusion happen

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My daugther did special work on the 'lattice' models related to quarks in the nucleus. I can tell you, that isn't physics or mathematics for anyone who isn't very advanced in those subjects - field theroy knowledge is essential.

That said, the liquid drop is 1940's but still very useful for certain nucliei. The far more modern (and accessible) approch is the shell model as Richard mentions. Protons assoaiate with protons, and ditto for neutrons, forming a series of seperate shells (energy levels) within the nucleus. I've read only bit but there are a lot of accessible articles for amatures up to experts.
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Re: Quantum world views - It's what make fusion happen

Post by Nicolas Krause »

Richard, the book I'm currently reading is arguing that a shell model has an inherent weakness in that the Mean Free Path it assumes for protons and neutrons simply doesn't match the experimental data. Obviously the author is presenting a bunch of data in support of his position, but given the fact that I have zero experience in the field I'm unable to judge whether or not this is a reasonable criticism. Does this track with your understanding of the shell model?
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Re: Quantum world views - It's what make fusion happen

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Shell models have always had their ups and downs since the 60's. At some point, the nucleus might be understood in some electrostatic and nuclear force balanced manner. There has been talk of an alpha or helium nuclear module model that still holds on in the minds of a good number of physicists.

I have always wondered more in relation to the neutron as the most mysterious component of the nucleus. It solves issues within the nucleus,(beta decay), yet outside the nucleus, it splits into a standard proton and electron within a debatable half life of about 15 minutes. Early attempts and experiments of less than suitable results ranged from 12 minutes to 20 minutes. reliable results in the early 2000s have placed it very close to 15 minutes.

Ask about why neutrons decay outside the nucleus, but are stable within the nucleus, and the internet will spit back explanations that roam over a lot of ground in a very convoluted post that is designed to leave you still musing over what was just put before you. Unsettling to be sure, but it is mostly a nice pat on the head saying "we don't know for sure", but leave you thinking that outside the nucleus, its mass is to great for its constituent parts so it breaks up....huh?

Yet based on the charge diagram in this posting below, it is known that neutrons, while electrically neutral when observed at range (macroscopically), The neutron viewed at the quantum charge level is indeed a shifting blob of both charges. I have always felt the the neutron is a quantized, crushed hydrogen atom that is unstable in nature, but kept electrostatically stable by nuclear protons about it within a stable nucleus. Once the ratio of neutrons to protons reaches some value, the atom is either stable or emits a beta particle, (electron from neutron decay). This may or may not re-establish the new elemental atom's stability. High Z atoms at Bismuth or above tend to emit entire hyper stable alpha particles. The new atom's resulting from Alpha emission may or may not be stable, emitting a beta particle and so on until a final stable balance of neutrons and stabilizing protons about them cease further decay. Needless to say, a smattering of nuclear gamma rays abound in many of these decays to throw off remaining energy imbalances. It is important to realize that 100% of all extant neutrons are first forged in stars via the ultra rare 10e-13 cross section fusion of H + H and probably +e. After all, there is no more significantly pure plasma, (proton-electron soup), than at the core of a star. The first stable atom is deuterium. Once that is forged and that first neutron is added to the proton, complex matter can be formed from that point on.

Read and try and digest this offering related to the neutron decay issue.

https://www.sjsu.edu/faculty/watkins/ne ... e%20stable.

In the end, be happy that this is all murky for it leaves much to be discovered. Once all the questions are answered, science will cease to exist. Not a good thing.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Quantum world views - It's what make fusion happen

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An interesting issue for neutrons (free) is decay time. Apparently there is a possible differnce depending on the method used . This may just be an error or might mean new physics.

Can read more at: https://www.energy.gov/science/articles ... n-lifetime
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Re: Quantum world views - It's what make fusion happen

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Nice article Dennis. Thanks. For years the lifetime was on the order of 20 minutes. Recently in some articles it was 10 minutes. Now it is heralded around 15 minutes. The snag as mentioned is that in one test two absolute measurements are required. We know that an absolute measurement of the precise number of neutrons emitted from ~10e6 fusions is just not possible. When looking for precise lifetimes of this neutral particle, the demanded two absolutes may be a bridge too far.

The neutron has captivated me since college. Protons and electrons are just there, but not one single atom beyond hydrogen can't exist without the neutron. The neutron is the key to the nucleus and all elemental atoms in our universe. Many questions, many theories, lots of experiments but the neutron's secret remains hidden. I have always and still believe the strong force is found in the neutron and the weak force is electrostatic in nature due to the hyper short sub-fermi distances in the nucleus. After all, they often call it the electro-weak force.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Quantum world views - It's what make fusion happen

Post by Dennis P Brown »

Your most welcome. And you are correct: the weak force is related to the electrostatic - at high energies, those two forces become one and the same. At lower energies, they differ as does water vapor does to water - same thing (electrostatic) but diferent phase (range of action.) So while the weak force is short range (though far stronger than the electrostatic in that region) it is, as you point out, due to its restriction to nuclear distances. Neutrons do, in fact, as I understand/recall, play a major factor in the strong nuclear force (due to gluon leakage - fall off range.)
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Re: Quantum world views - It's what make fusion happen

Post by Colin Heath »

Fantastic food for thought and I wonder if my simplistic understanding is correct?

All the fusion we know of / understand occurs via quantum tunnelling. And if that’s the case, the search for much higher temperatures and more energy doesn’t really further fusion.

Is it correct the only way we will achieve break even is with a scaled version so large it won’t be practical?

Are there ways of influencing an increase in quantum tunnelling other than increasing the amount opportunities for it to occur (scale).
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Re: Quantum world views - It's what make fusion happen

Post by Liam David »

The tunneling probability is directly related to the nuclear kinetic energies through the Gamow factor, which scales as P ~ exp(-sqrt(1/E)). Increasing the grid voltage increases the deuteron energies and the effective temperature (E ~ kT), thus raising the probability that a given collision will cause fusion.
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Re: Quantum world views - It's what make fusion happen

Post by Colin Heath »

Thanks Liam,

Are we talking collisions in the sense of colliding or through tunnelling? I was under impression that trying to overcome Coulomb barrier was near impossible and almost all fusion is now believed to be from tunnelling.

Hence why the sun works because of sheer number of chances for tunnelling and as such, we couldn’t scale to what’s required on earth.

Very interesting subject and looking forward to being informed and trying to inform myself.
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Re: Quantum world views - It's what make fusion happen

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The deuterons rarely collide physically. In the quantum world, the particle's barrier to the strong force overcoming the electrostatic repulsion varies. As such, a full on slam dunk hit at our energies is a game of probability more or less. At our level of operation, we are relying on a hit or even a near pass by at the same time the tunneling possibility is at a maximum for one or both particles as they approach. This goes back to energy as stated above. For targeting in our mechanical brains more energy means the quantum tunneling target size of the particles swells ever larger and larger as the kinetic energy of the particles increases.

In the Oppenheimer-Phillips reaction, there is so much energy that the deuterons are torn apart and will never fuse. So there is also such a thing as too much energy.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Quantum world views - It's what make fusion happen

Post by Colin Heath »

Thanks Richard,

That makes sense to me with your explanation along with Liam’s.

More learning to do, much more.
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Re: Quantum world views - It's what make fusion happen

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There is the Lawson criteria....Read up on this for details. Remember energy is related to temperature. In solid matter or in a dense plasma there are constant collisions. Power fusion demands a very dense plasma, totally contained at very high particle energies. The containment is always the issue. As power fusion begins, the huge fusion energy output heats the dense plasma which wants to expand and cool. We do not want it to cool. Thus, more containment is demanded. In the real world on earth, the containment is always found to fail. The plasma expands, and this burns or otherwise damages the walls of the reactor. The debris then kills the fusion event. The power phase used to last a fraction of a second. Better containment moved this to a second or more. The latest can last a few seconds before it craps out.

Needless to say, in the production of real power for electricity we have grown use to power plants running smoothly 24-7-365 without real issues. 3 to 30 seconds of powered run time is kind of a total fail.

The fusor is a thin, totally lossy plasma where only a very few of the collisions occur at the desired fusion energy of the applied voltage. The deuterons, be they multi-pass, acceleratory recirculations or one-shot passes before ion death, only fuse with great rarity related to their number. Still there are enough fusions in the best fusors to create 1 to 6 millions fusions each second! This produces enough neutrons to make the reactor a nice experimental source of neutrons. There is no hope by any artifice where a fusor can produce power. It can only do massive power losses.

Make sure you read every FAQ in this forum if you wish to gain knowledge of how the fusor does fusion and on fusion in general. When talking fusion energy output of the fusor, this FAQ is a must see and to understand.

viewtopic.php?f=42&t=13284

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Quantum world views - It's what make fusion happen

Post by Justin Fozzard »

I find it very interesting and surprising that it is possible to trap neutrons and in a variety of ways.

Here is a rather good presentation about neutron trapping and a couple of papers on the subject:

Huffman 2000 Magnetic Trapping of Neutrons.pdf
(227.72 KiB) Downloaded 480 times
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Re: Quantum world views - It's what make fusion happen

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Great URLs! Thanks Justin. I have always been amused that the neutron drops just like a rifle bullet in a gravitational field. Acceleration in a gravitational field for a neutron is no different from a lawn dart. The issue is how far can it go based on its velocity normal to the field. Ultra cold neutrons make good candidates, but getting them cold enough in a beam to work with is like herding cats in a violent thunderstorm.
Good controls in any experiment regarding lifetime measurements is key.

I always wondered if the decay is purely exponential with a fixed half-life the instant they are free or does their velocity relative to us in measuring them make their life times or "half-lives" a matter of relativistic time dilation. Relative to themselves the decay may be instantaneous. A single coupled proton-electron pair, extra-nuclear, would have a tremendous coulombic repulsive force.

Based on the many methods used in magnetic confinement and the many analyzed and reported systematic effects, what role in altering our perceived and measured lifetimes might these have? Just because we force collected near zero energy neutrons into a bottle under intense magnetic fields, the known electrostatically lobed neutrons may view themselves as in a friendly but very weak inter nuclear environment.

Issues abound here and might be lumped under systematic effects yet to be understood.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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