We are not easily fooled

Reflections on fusion history, current events, and predictions for the 'fusion powered future.
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Richard Hull
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We are not easily fooled

Post by Richard Hull »

One thing about landing on this site and actually doing fusion........

We are learned in many ways related to the "doing" of fusion. We see and understand the technology and the difficulties. The best of us understand the theory to greater or lesser degrees. We can sniff out a snow job and categorize it rapidly as such. The best of the best in physics can't snow the long attendants here. That is, both the most hopeful here and the most dubious of power fusion success can not be easily manipulated into believing a process that is way off base and detached from experiment or common sense based knowledge that has come with the doing.

We are not experts nor are we nuclear physicists. We are something less and yet, in some ways, more.

We see just how hard fusion is in that we are forcing, against nature, the union of recalcitrant nuclei requiring vast amounts of seed energy. We realize that were it not for quantum tunnelling, we nor any tokomak, JET or ITER group would ever fuse. As Don Lancaster, (energy commentator and free energy debunker), would say regarding nature or physics, "It's the only game in town and the game is rigged, you will never win".

Fusion must, by its nature, be very difficult to virtually impossible or the universe would be aflame and burned to a cinder in a couple of million years. In this universe, fusion requires the potential energy of gravitational containment which is indeed free about large masses to generate energy that slowly rolls the quantum dice over vast amounts of nuclei. What is, by the laws of physics, a net loser process becomes the long burning nearly in-exhaustible energy of the cosmos.

We realize that the maxwellian tail in the process is no place to hang your hat or hopes. I, personally, worry that thermal fusion scaling factors coupled with scaled attempts at containment are a dream not too far removed from a perpetuum mobile. I fear in a distant future, the current efforts will be a source of great mirth to those who will put it on a scale of the alchemists trying to turn lead into gold.

This leaves my only hope for future fusion energy relying on some as yet unseen, unrecognized or unborn, "lucky donkey". We await fusion's equivalent Roentgen or Becquerel.

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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Paul_Schatzkin
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"Quantum Tunneling"

Post by Paul_Schatzkin »

Richard, this sentence piques my curiosity:

"We realize that were it not for quantum tunnelling, we nor any tokomak, JET or ITER group would ever fuse."

Can you tell us what role "quantum tunnelling" plays in fusion?

I'm curious because that phrase was tossed in my path during the Townsend Brown odyssey, for reasons that are still not clear.

And you know what was the end of that tunnel: No locomotive, just more tunnel.

--P
Paul Schatzkin, aka "The Perfesser" – Founder and Host of Fusor.net
Author of The Boy Who Invented Television: 2023 Edition – https://amz.run/6ag1
"Fusion is not 20 years in the future; it is 60 years in the past and we missed it."
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Richard Hull
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Re: We are not easily fooled

Post by Richard Hull »

My entanglement with quantum physics is limited to self study, but here goes. We fuse mostly with high speed deuterons in collision in velocity space and not in a plasma.

The deuteron is an ion and is the deuterium atom stripped of its single electron.

The deuteron has an electrostatic charge of +1, chemically and ionically and so far as any future atomic nuclear reactions are concerned.

Similar electrical charges repel and, thus, deutrons repel each other as they get close to one another.

The closer deuterons get to each other the more intense the force to repel gets, such that they can never touch mechanically.

The fusor attempts to force deuterons to "collide" and fuse.

Earlier in the last century, when fusion was discovered ~1932, quantum mechanics was new. Part of the theory states that, given two ions (nuclei) heading towards each other at some collisional energy, X, there is some probability, Y, that the potential barrier represented by the columbic repulsion will be "tunneled through" at a quatum level deep enough to have the "nuclear strong force" grab on to, or overcome the columbic force, thus, fusing the deuterons together. It is all more mathematically complex than this, but this is the upshot of how all fusion is done. That's 100% of all fusion.

This is the sticking point in all fusion attempts! You have to supply enough seed energy, (tremndous amount), to attempt to get enough deuterons up to energy inorder to have enough probability of fusing enough atoms to just equal or surpass the seed energy. The equation governing this complex relationship is referred to as the "Lawson criteria"

An analogy of failed fusion or fusion in our fusors and all other fusion reactors to date, follows..........

*******************************************************************************

Jimmy pays 1 cent for each chance to throw three, ten-sided dice. Each time they total 30 he is a winner and given a dollar. He furiously throws the dice for 10,000 times and winds up with $28.00. He spent 10,000 pennys, $100.00, to get $28.00. Sure! You guessed it. The game is rigged by unresolvable probabilties stacked against him. What is the probability he will spend a dollar in pennies and walk away with $100.00? Ha! This analogy is not perfect, but shows fusion for what it is......a dice game.

In stars, once born, there is always a Jimmy, (gravitaional energy), rolling the dice! Thanks to a virtually inexhaustable supply of pennys (hydrogen atoms) the game virtually never ends. Naturally, due to probability, Jimmy wins a certain amount and a large number of dollars, (taken from his pennies), are sent home to mom and the family....(Fusion energy sent out into space to warm and illuminate planets to support life). However, all those penny's spent on jimmy's rolls that were not winners, recycle into Jimmy's supply of future available pennys for new rolls of the dice.

Jimmy lives for billions of years until he exhausts his penny supply by winning enough to deplete his stash of coins. In frustration, he goes apoplectic and explodes.

Were the odds different, (nature's laws of fusion physics), and the game used two, two-sided dice and a four resulted in a $4,000,000 payout from his penny supply, the game would be over, (the universe would end), in a twinkling. Lucky for jimmy and the folks back home, (and the universe), the rules were made up for born suckers such that Jimmy would game his heart out for billions of years and mom would have a long and steady income.

Jimmy was never in it to win, over the long haul. He was in it to play the game and to support mom and the folks back home. The reason he even lived so long was that he lost so often that the bulk of his expenditures stayed with him. Only his winnings, a tiny fraction of his reserves, ever left.

*********************************************************************************************

We've done fusion in our fusor as noted above by smashing through the potential barrier in some small fraction of the rolls of the quantum dice. What now....?

Now our two deuterons are fused. But wait! All is not over! The reaction is unstable once it occurs, even though the two protons and two neutrons from the crashed and fused nuclei equal the nucleus of one of the most stable atoms, standard balloon helium 4He. The fused nuclei form a 50:50 probable outcome. In one reaction, a triton, (tritium nuclei), is formed along with a free flying proton. In the other reaction, the very rare 3He, (bizarre helium), is formed along with a free flying neutron. Only once in about every 10,000 deuterium-deuterium fusions will a single 4He, (balloon helium), atom be the result. Don't ask me why, it is just the observed result.

I have given my best stab at a simple explanation of quantum tunneling. It is a probabalistic reaction, based on the nuclear cross sections of the nuclei at a specific collisional energy. The cross sections are an empirically arrived at, effective diameter of the colliding nuclei. The bigger the cross section, the more likely it is that fusion and quantum tunnelling will occur.

I am so glad you queried me on this point as this is all part of the understanding that the lay mind rarely has contact with or in which a real understanding is attempted to be given.

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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Chris Bradley
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Re: We are not easily fooled

Post by Chris Bradley »

A picture paints a thousand words!

You need less energy if you 'tunnel' underneath the high energy required to overcome Coulomb repulsion.

When the conditions are right, there is a small but finite probability that a high energy +ve nucleus can reach the big energy null, close to another +ve nucleus, by digging its way [green arrow/path] underneath the electrostatic peak.

Quantum tunnelling means fusion can happen readily at 10's keV, whereas 'classic' Newtonian mechanics [blue arrow] says nothing should happen until MeV (which would be well-beyond the capabilities of plasma experiments like tokamak, as well as very difficult for IEC).

Image

There were inklings long before Gamow expounded the principles of quantum tunnelling that fusion happened at lower temperatures than Coulomb's law would suggest. Sir Arthur Stanely Eddington had the insight some years before, saying; "I am aware that many critics consider the stars are not hot enough. The critics lay themselves open to an obvious retort; we tell them to go and find a hotter place." Later, Bohr urged Gamow to study in Cambridge with Rutherford, knowing that Gamow's work could unlock the realisation that their p+Li accelerator could yield results at much lower acceleration voltages than expected. While other labs in the world worked towards MeV colliders before attempting experiments, the Cavendish team stuck to much more practicable 100's keV accelerations and were rewarded with the accolade of being the first to 'split the atom'.
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Re: We are not easily fooled

Post by Frank Sanns »

A more efficient route towards fusion would then not be to collide with higher energies but rather find a way to tunnel better. Alternatively, if you could shield charge of the nucleus you are in again.
Achiever's madness; when enough is still not enough. ---FS
We have to stop looking at the world through our physical eyes. The universe is NOT what we see. It is the quantum world that is real. The rest is just an electron illusion. ---FS
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Re: We are not easily fooled

Post by prestonbarrows »

There is a similar situation in reverse that allows for things like alpha decay in the heavier elements. If I remember correctly, this was the context where the concept of tunneling was first developed.

In a classical world, an alpha could never climb out of the deep potential well created by the nuclear strong force and escape the atom. Solving Schrodinger's equation one finds that the wave function of a particle decays exponentially in regions where it does not have enough energy to reach classically. This means that for a barrier of finite width, there is always some finite wave function (probability of observing the particle) remaining on the opposite side of the barrier. So, as the subatomic particles are bouncing around inside the nuclear potential well, there is a finite probability that the particle will 'tunnel' through the barrier and appear outside the nucleus where it is quickly ejected due to Coulomb repulsion.

Note that the particle never actually is in the forbidden region in the classical sense; it simply spends some of its time outside of the well. From the perspective of QM, location is 'fuzzy' and this ties into the idea of the uncertainty principle. An important point is that these quantum processes deal with probabilities. This helps explains the probabilistic nature of alpha decay, half lives, and other nuclear processes.

Image

On the flip side, this is also why fusion is described by cross-sections which are inherently probabilistic.
Frank Sanns wrote:A more efficient route towards fusion would then not be to collide with higher energies but rather find a way to tunnel better. Alternatively, if you could shield charge of the nucleus you are in again.
This is basically the idea behind Muon-catalyzed fusion. Muons are something like very massive electrons. Replacing an electron with a muon in dueterium or tritium changes the Coulomb potential and makes fusion reactions much more probable. This has been experimentally demonstrated. The problem is muons are unstable with very short lifetimes and tend to fly away. At least so far, one needs to put in more energy to create the muons than gained from the boosted fusion rates.
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Richard Hull
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Re: We are not easily fooled

Post by Richard Hull »

In addition, 100% of all muons exist at energy levels of 100mev and above or they are no longer muons. It is also why they are out of the amateur's grasp in any fusion attempt.

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
Benjamin Abbatiello
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Re: We are not easily fooled

Post by Benjamin Abbatiello »

If Jimmy is gravitational energy, who are we?
It is a great act of cleverness to be able to conceal one's being clever.
-Francois de La Rochefoucauld
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Richard Hull
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Re: We are not easily fooled

Post by Richard Hull »

What are we?!

We are mere bottom feeding, self agrandizing muddlers who aspire to and are envious of Jimmy's power, looking for work-arounds and praying for the "lucky donkey" to be born among us.

Ricahrd 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
Benjamin Abbatiello
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Re: We are not easily fooled

Post by Benjamin Abbatiello »

Or are we a parasite who strives to manipulate Jimmy's mind to the best of our seemingly infinitely weak power, as compared to that of - once again - the unquenchable thirst for logic that physics seems to have? Perhaps another one for theory...
It is a great act of cleverness to be able to conceal one's being clever.
-Francois de La Rochefoucauld
Mark Stockman
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Re: We are not easily fooled

Post by Mark Stockman »

I'm interested in what you folks (the fusor community) have already accomplished. Phoenix Nuclear Labs is selling fusor-based neutron generators which they claim produce 10^12 neutrons per second with straight Deuterium and 10^14 with the D-T reaction. They're also claiming continuous operation and a lifetime measured in years, not hours. That's pretty awesome. If you can produce enough thermal neutrons cheaply and reliably enough, that makes a subcritical fission reactor practical. So fusor technology could be very useful to energy production without needing to reach break-even.
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Richard Hull
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Re: We are not easily fooled

Post by Richard Hull »

I wonder about their claims. The 10e12 n/s for D-D is doable but is a stretch. Then in the next sentence they use the claim that this FLUX exceeds any other source other than a nuclear reactor. 10e12 n/s is not a flux.

I think your sub-critical fission reactor run off of a hail of neutrons is a pipe dream. A lot of real physics bars your way.

We are not easily fooled.

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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Jim Kovalchick
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Re: We are not easily fooled

Post by Jim Kovalchick »

I see no practical reason for a so-called subcritical reactor. The biggest safety challenges of a fission reactor, those associated with decay heat, would remain, and the practical aspects of managing a flux independent of the fission generated flux are a large hurdle. Can someone enlighten me?
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Richard Hull
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Re: We are not easily fooled

Post by Richard Hull »

I think this is one of those many still-born ideas that looks interesting to someone barely into the field, but is doomed to never advance to the useful engineering phase for a myriad of reasons based on the physics and practicality. I don't think any enlightening is needed on this one.

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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