Electron's magnetic moment in plasma/fusion physics?

Discuss how polywell fusion works; share theoretical questions and answers.

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D Tibbets
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Re:

Postby D Tibbets » Tue Jan 10, 2017 7:03 pm

jarek wrote:..... and then small blue text on the bottom says that Eganowa analysis says that surprisingly the amount of energy generated by star decreases with increase of temperature of the core, what is consistent with his theory of electron assisted fusion (he calls it 'molecular mechanism of nuclear synthesis') (?)....


Other elements may be significant, but that Stars put out less energy (per unit volume/ density is well understood and reasonable with current understanding.
A star's core temperature is a straight forward application of the gas law. The core heats up[ through gravitational collapse till the gas outward pressure equals the inward pressure due to gravity. As the core losses heat through convection and radiation to the outer layers of the star and finally into space the core cools and the gravitational pressure becomes dominate and the star/ core shrinks further till a new balance is reached. Except, with fusion as a heat source you do not need to use additional gravitational potential energy to keep the core hot and in pressure equalibrium. The star is stable- in the so called main sequence phase of stellar evolution.

Things change as the star core starts running out of hydrogen, to maintain the pressure equilibrium against gravity it shrinks some and heats up till helium can start burning via the tri alpha process. As the helium burns up heavier produced elements start burning , like carbon,etc. All of these derivative reactions require higher temperatures, the core shrinks and becomes hotter- simplistically the gravity heats up the core and fusion maintains the temperature once reached. Each of these fusion steps produce less energy per reaction, as is obvious via the nuclear binding energy curve. At Ni62 there is a balance point, reactions just lighter than this produce relatively little energy compared to hydrogen- hydrogen fusion. Past Ni62 energy is actually absorbed with fusion.

As the star burns and sequentially burns up the lighter elements, each set of fusion reactions produce less energy per reaction. Because of this, to maintain the core pressure against gravity, the fuel needs to burn faster- which it will as the temperature increases. This is why a star can burn hydrogen for ages , but as it eats through the produced heavier elements the star ages faster, till it runs out of energy producing fusion fuels or the gravitational pressure cannot heat the core any further- to the degree necessary for the heavier element fusion to continue . Further considerations about the stars mass, and end of life physics then makes things further interesting.

The P-P reaction starts with two protons fusing with an electron also incorporated and (I think) a neutrino involved. This produces some energy, but it is important to remember that this is only the start of the P-P process and is the rate limiting step. Once the deuterium is made, it very quickly reacts with further protons or another deuterium to eventually produce helium4. This releases a lot of energy . Also, keep in mind that there is an alternate pathway. The CNO cycle. This takes a little higher temperature to surpass the P-P process. In the Sun it accounts for about 10% of the fusion output. In a larger star with greater inward gravitational pressure the core heats up and the CNO cycle becomes the dominate source of fusion energy (at least in metal rich stars). The CNO fusion cross section curve is much steeper than the P-P reaction curve. Thus, with a modest increase in core temperature, an exponential increase in the hydrogen fusion rate occurs. This is why a star with many times the mass of the Sun, has a core temperature only mildly greater- perhaps 30 million degrees. This is well below the ~ 100 million degree temperatures required for the tri alpha process of helium4 burning to contribute. The core size/ volume and thus the amount of fusion necessary to maintain a balance may be much greater but the temperature within that core is only mildly increased. This is why larger higher mass stars burn through their hydrogen supply faster, despite starting with initially larger supplies.

Stellar dynamics and evolution is a rich field of study. I hope this few snippets illustrates the need for caution when taking simple small claims as meaningful. They may be true but are taken out of context.

As for the electrons magnetic moment contributing , I have little understanding. But, that has never stopped me before! The key point may be the orientation of the electron spin and thus the direction of the magnetic moment. The electron may be moving in or out and have transverse motions as well. The balance of forces will depend on the sum of these motions. In cooler conditions- non ionized atoms, the electrons are paired up with one up and one down spin so the net effect is grossly zero. I use the word grossly as supple imbalances plases a role in atom behavior and molecular bondine etc. The field of spintronics is seeking to utilize these processes to add to the utility of systems, as compared to the traditional electrical interactions. If this may have a role in behavior in the harsh and extremely dynamic area of plasmas is intriging. But, consider that the electromagnetic force is a combination of electrical and magnetic properties. It is already incorperated in the electromagnetic force that governs Coulomb attraction and repulsion.

Dan Tibbets
To error is human... and I'm very human.

D Tibbets
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Joined: Thu Jun 26, 2008 6:52 am

Re: Electron's magnetic moment in plasma/fusion physics?

Postby D Tibbets » Tue Jan 10, 2017 7:15 pm

Concerning tritium in lava. The claim may have merit, but again take nothing at face value. A brief search turned up this article about vented steam from magma. It is actually from nuclear bomb testing- atmospheric water that has rained down and then been converted to steam from the heat of the magma.

https://hvo.wr.usgs.gov/volcanowatch/ar ... 04_20.html

Dan Tibbets
To error is human... and I'm very human.

jarek
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Re: Electron's magnetic moment in plasma/fusion physics?

Postby jarek » Wed Jan 11, 2017 12:09 pm

First of all, let me remind why electron's magnetic dipole moment seems important from the point of view of fusion - I think the most crucial are back-scattering (on nucleus) type of electron trajectories due to the resulting Lorentz force, like (from simulation):

Image

If you imagine that there is another proton approaching from the direction of this trajectory, electron can remain between the two nuclei, screening the Coulomb barrier and finally leading e.g. to p-e-p fusion into deuteron.

This is kind of nonstandard ("dual") Lorenz force: for magnetic dipole (electron) traveling in electric field (of nucleus) - one of many EM dualities ( https://en.wikipedia.org/wiki/Duality_( ... _magnetism) ).
It would have exactly the opposite sign if the nucleus would be the magnetic dipole (in fact it is, but thousand times weaker).
To see it, for a moment make a boost so that electron stays and nucleus travels - in magnetic field of electron's magnetic moment, so Lorentz force acts on the proton ... but due to 3rd Newton law opposite force acts on the electron.
Here is a more formal derivation:
Image

I have managed to contact Eganova, but only got materials in Russian and couldn't find the details for the claims from the citation above.
The big problem with Sun is that it is believed that the core has only ~15MK, what gives ~1.4keV thermal energy per dof ... while for fusion we need to take e.g. protons to ~1fm, what needs >1MeV energy ... the temperature is thousand times too low.
The standard Gamov's explanation is quantum tunneling, but this is kind of magical explanation: proton teleports through energy barrier ... electron's assistance might bring a nonmagical understanding: help of electron maintaining trajectory between two nuclei, screening the Coulomb barrier and so making fusion much more probable - this "molecular fusion" of Gryzinski and Eganova, where dependence on temperature is far more nontrivial: such electron trajectories need stability, made more difficult while increasing temperature.

Regarding arguments for fusion inside our planet, the strongest I have seen concern tritium production in volcanoes - it quickly decays to He3 and amount produced in fission is nearly negligible - some volcanoes produce like 10000x more tritium than standard ways could explain:
http://lenr-canr.org/acrobat/JonesSEgeofusiona.pdf
Also, in some rocks there are found helium concentration up to 7% ( https://en.wikipedia.org/wiki/Helium ) - could you imagine getting such concentrations from alpha decay only?

ps. nice animation about 1-10 electron atoms in free-fall atomic model: https://www.youtube.com/watch?v=P2IsIkSn5bk
my slides: https://dl.dropboxusercontent.com/u/124 ... efall2.pdf
Gryzinski's papers (3000+ citations): https://scholar.google.pl/scholar?hl=en&q=gryzinski

D Tibbets
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Joined: Thu Jun 26, 2008 6:52 am

Re: Electron's magnetic moment in plasma/fusion physics?

Postby D Tibbets » Thu Jan 12, 2017 4:28 am

The electron interaction with the proton is certainaly significant but tiny in terms of electromagnetic shielding between two protons. My understanding is that this is because of the relative distances involved. A proton needs to approach another nucleon -proton in this case to such close distances that the mutual repulsion due to electromagnetic interactions is huge. This repulsion may approach ~ one percent of the strong interaction (which of course only becomes dominate when the protons are less than ~ 4 proton diameters separation because the carrier of the strong force can only travel about this distance before decaying). For an electron to shield against the mutual proton repulsion it has to be at a closer distance . This is apparently a rare event in most situations. Keep in mind that the electron is prevented from being in the immediate vicinity of a proton due to quantum mechanics . It can shield the incoming proton for a bit and this may decrease the distance that the incoming proton has to decelerate. This may effect the fusion probabilities to some extent and is figured into the fusion cross section curves. In cold matter (atoms) some heavy elements have orbitals that may actually penitrate the nuclear volume. Yet these elements do not fuse easily. Again, keep in mind that as Z increases, the number of protons increase and the electromagnetic repulsion against any test proton increases as a function of the sum of individual proton contributions. Increased electrons does not necessarily imply less proton repulsion from a nucleus. It is complex.

Having said all of this there are nuclear reactions where electrons are actually absorbed with a proton - so called reverse beta decay. This is the first step in P-P fusion in a star- and is why it is such an unlikely event. The cross section is about 10^20 times smaller than typical D-D cross sections.

Also consider Muons. They are "electrons" with about 40 times the mass. Quantum mechanics permits much closer approaches to nuclei/ protons and the resultant shielding can considerably increase fusion probabilities. Here the problem is not fusion probability but the harvesting/ production and management of the Muons. They just breakdown too fast.

And finally, consider our existence. If some of of the proposed interactions actually occur, then we probably would not exist. Unless you can explain how to work around the effects, the universe would be a much different place.

Dan Tibbets
To error is human... and I'm very human.

jarek
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Re: Electron's magnetic moment in plasma/fusion physics?

Postby jarek » Thu Jan 12, 2017 7:11 pm

Regarding electron screening, imagine p-e-p initial symmetric situation - Coulomb force says that proton is four times stronger attracted by electron than repulsed by the second proton.
It seems initial symmetric p-e-p situation should collapse (into deuteron) - just like that.

However, the standard counterargument is quantum mechanics - that this electron becomes a relatively huge (10^-10m) probability cloud - which has no chance to remain between the two protons to screen their repulsion during the most crucial phase of the fusion (pm -> fm distance).
From the other side, electron's unitary charge is believed to be indivisible, its size is experimentally bounded e.g. by 10^-22m in Penning trap ( https://en.wikipedia.org/wiki/Electron# ... properties ).

So the real question is if quantum probability cloud is:
- fundamental - the indivisible elementary charge is objectively smeared into a huge volume, or
- effective - as in other probabilistic models, probability cloud only describes some average, or our incomplete knowledge.

While there are e.g. 10^-22m experimental boundaries for electron's charge, is there a single experimental evidence that it can be objectively smeared into a huge quantum cloud?

My road to realizing that the probability cloud is only an effective description has started with Maximal Entropy Random Walk (MERW) about 2008 - choosing the safest possible random walk: the maximizing entropy way.
The standard way, leading e.g. to Brownian motion in continuous limit, turns out to only approximate this entropy maximization in inhomogeneous space (like proton vicinity).
Doing it right by MERW turns out to lead to exactly the quantum ground state probability distribution: squares of coordinates of the dominant eigenfunction/vector of Hamiltonian - the quantum probability cloud appears just naturally if doing thermodynamics right, also for point entities.
our PRL paper: http://journals.aps.org/prl/abstract/10 ... 102.160602
slides: https://dl.dropboxusercontent.com/u/124 ... sem_UJ.pdf
my PhD thesis: http://www.fais.uj.edu.pl/documents/416 ... 74256fd065
Conductance simulator: http://demonstrations.wolfram.com/Elect ... ndomWalks/
diagram with example of evolution for defected lattice (there are self-loop in all vertices but squares):
Image

Agreeing that quantum probability cloud is only our effective description - that objectively electron's charge remains indivisible, there appears these trajectories remaining between the two nuclei - making fusion much more reasonable.
... but not simple - still the probability is tiny, requires some small space of initial parameters - electron's assistance only increases the chance from practically impossible to statistically noneligible.

update - Wikipedia article about MERW: https://en.wikipedia.org/wiki/Maximal_E ... andom_Walk


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