[jamesr]

NoSmoke wrote:
james: If the He ions simply spiral around in the plasmoid until they loose their excess energy, how then would then generate net energy when finally expelled from the plasmoid by the magnetic field collapse? It would seem the energy imparted to those ions would only then be obtained from the collapse of the magnetic field which in turn was created by the input energy (which it seems to me would result in no net gain).

I believe some of the He energy end up in the magnetic field, indirectly via interactions balancing the gas pressure pushing out as it heats up and magnetic pressure inwards. But the way I think of it is that them beam energy is mostly just recycling the energy put into the system by the capacitors. So if you have a relatively cold DPF device (ie not hot enough to expend a significant amount of its energy in radiation losses) with a coil collecting energy from the beam(s) then you try and get as much out as you can back into the capacitors. The difference with fusion in there is that the pinch could be maintained at 100’s keV for 10’s ns radiating all the rest of the energy in X-rays. So by collecting the X-ray energy you not only overcome the less than 100% efficiency of gathering back of the input energy but also gather some of the gain from the fusion. Hopefully ending up with a nett gain overall.

You will never get nett gain from the beam alone.

[jamesr]

Of course the ‘Lines’ our just our way of plotting contours on a graph, much like meteorologists plot isobars on a weather map. On a weather map, the topology of the isobar lines can change as areas of high or low pressure merge. When we talk about magnetic reconnection it is the lines on our magnetic map that ‘reconnect’.

However it does have a very real and physical consequence…. Since ions and especially electrons are “frozen” in to follow the direction of the magnetic field, gyrating around in a helical motion, they are confined to that topological region of space.

Using the astrophysical example again; an electron caught in Earths magnetosphere must remain in Earth’s magnetosphere. Similarly an electron in the Solar wind is confined to the Sun’s Heliosphere. When they connect, on occasion, in the tail, ions and electrons from the solar wind can pass into the Earths magnetosphere, where they stream down the field towards the poles hitting the upper atmosphere causing the aurora.

[jamesr]

zapkitty wrote:

… he stipulates that “fuel must be injected in small quantities in order to prevent uncontrolled magnetic reconnection” – i don’t think this should be much of a problem seeing as there is no such thing as magnetic reconnection!

Is there a magnetic reconnection conspiracy?… 🙂

The simple MHD fluid models do not fit observations of reconnection very well (for example in the tail of Earth’s magnetosphere causing bursts in auroral activity).
But newer extended Hall & two-fluid models are much closer. To fully capture the dynamics of reconnection you need a fully kinetic simulation, that can cope will relativistic electrons. Which some 2D computer simulations can now do for simple scenarios, but large full 3D ones are still a few years away.

If you want to see some simple animations of magnetic reconnection have a look at:
http://www.astro.virginia.edu/VITA/ATHENA/cs.html

[jamesr]

There seems to be a bit of confusion between the energy/direction/velocity of the He ions and the formation of the beam. They are more or less completely unrelated. I guess the important thing to consider is that you still get a beam of ions out of a collapsing DPF pinch (hypothesized to be a self contained plasmoid structure) even if you don’t get any fusion.

A collapsing DPF pinch will always create the electric field accelerating ions and electrons into a opposing beams. As Zapkitty says the electron beam losses a lot of its energy as the electrons try and plough through the plasma, but the heavier ions have enough inertia to carry on out through the surrounding plasma.

rickPS: Yes the He ions will be emitted in random orientation away from each other – although not all three out from a point in a triangle, instead the excited C12 spits out one He4, then the leftover Be8 almost immidiately splits into the other two He4, conserving momentum in each case. These He ions although traveling very fast don’t get very far as they are still bound to spiral around the magnetic field lines.

If B = 1GG = 10000 Tesla, and the 2.9MeV He4’s have a velocity of ~1.2e7m/s then in the ‘worst’ case when the He ion is emmitied perpendicular to the B-field the radius of curvature is: 0.02mm

So the He ions will just spiral around in a small volume the field having collisions with the other electrons & ions in the dense plasma of the pinch, heating it up. Such that each He will lose all its excess energy and become thermal within a few picoseconds, compared to the 10’s of nanosecond life of the pinch

[jamesr]

Arvid wrote:

Do you know a book with tables about cross sections for different elements, like proton or deuterium + element? It might be that D+B10 cross section is much higher than D+D at its peak value.

This is a little 30-page chapter from a larger book that discusses a number of reactions relevant to controlled fusion and fusion in stars. (Warning: PDF.) Unfortunately, nothing about D + B 10. Interestingly, it shows p + B 11 with a huge, but very sharp resonance at 146 kEV, before its main peak over 500. Could some machine be designed to take advantage of that?

The full book is “Tokamaks” by John Wesson

Although the resonance is important, the ions will be close to thermal equilibrium as so have a Maxwellian velocity distribution. If you refer to fig 1.5 on page 18 of the pdf, rather than fig 1.3 it shows the Maxwellian averaged fusion cross section. The averaged fusion cross section is slightly higher at temperatures below 100keV than it would otherwise be if you didn’t take the resonance into account. But to get to appreciable reaction rates you still need to be over 100keV.

You could try a to create a non-Maxwellian system eg a beam of protons at exactly that energy. But the energy you need to create a beam will always be many orders of magnitude more than the benefit.

[jamesr]

vansig wrote:

When the magnetic field collapses the rate of change in B-field creates the huge E-field which accelerates the ions in one direction at ~2.6±0.2MeV and the electrons in the other.

I thought the ions in the exit beam would average around 600 keV?

If their temperature (ie random spread in velocities) were 600keV then the beam would be ~2.6±0.6MeV. The energy in the beam comes from the huge, tightly wound, B-field transferring its energy to an E-field, which in turn transfers to the ions, accelerating them into the beam. The ions thermal motion is just superimposed over the top.

Also note, I have assumed all the fusion product He ions have completely thermalised in the plasmoid before the beam is formed – transferring the fusion energy partly to maintain the plasma temperature against X-ray losses, but also maintaining the B-field, until it’s eventual collapse.

[jamesr]

For anyone wanting to know any more I heartily recommend Feynman’s “QED – The Strange Theory of Light and Matter”

The full standard model of the all the quarks, leptons and Bosons still has a few flaws (maybe the Higgs will help – I doubt it though), but at the normal energies of electrons interacting in chemistry and dense plasma physics, Quantum Electrodynamics is all you could ever need.

[jamesr]

Aeronaut wrote:

Yes, the ion beam is fusion products, rather than either of the fuel ions.

I understood it is mix of products and unburnt fuel from the plasmoid. The fusion products start with high (8.7/3=2.9MeV) energy but are confined in the plasmoid recycling their energy and keeping the plasmoid hot (100’s keV) for ~50ns (ie thousands of orbits of the plasmoid). When the magnetic field collapses the rate of change in B-field creates the huge E-field which accelerates the ions in one direction at ~2.6±0.2MeV and the electrons in the other.

Also regarding the CNO type reactions, apart from the higher temperatures needed – the reliance on the beta+ decay of intermediates means the products must be confined for many half-lives of the radioactive decay – ie hours not nanoseconds. ie impossible in all but large hot stars.

[jamesr]

Brian H wrote: Oh, give it a while.

Why?
They have very little evidence. If the Focus Fusion Society is to be taken seriously it needs to be critical of all claims (LLP’s included).

This recent PR attempt, once they were rejected by all other peer reviewed journals to the extent that they felt the need to set up their own to publish it in, hardly qualifies as evidence.

Science should be based on repeatable, verifiable evidence. If and when they can specify their experiment in enough detail for it to be replicated by someone independent and the results scrutinized by others, then maybe I’ll give it a second glance

[jamesr]

I ‘m inclined to share this viewpoint from the article:

One comment in the forum contained a message from Steven E. Jones, a contemporary of Pons and Fleishmann, who wrote, “Where are the quantitative descriptions of these copper radioisotopes? What detectors were used? Have the results been replicated by independent researchers? Pardon my skepticism as I await real data.”

I think this thread deserves to be moved to the noise & ZPE category

[jamesr]

After a bit more idle browsing it seems one use of the p+Ni-58 reaction is the production of Ni-56 (for academic study into astrophysical processes) as the reaction when firing a 50MeV proton beam at a nickel target does not produce Cu-59 instead it is

p + Ni-58 -> Ni-56 + 2p

note the energy needed is 50MeV, this emphasizes the huge Coulomb barrier a heavy ion like nickel has, and why fusion at a few hundred degrees is VERY unlikely. This is the sort of reaction that normally only happens in supernovas

(source http://prl.aps.org/abstract/PRL/v80/i4/p676_1)

[jamesr]

vansig wrote:
if there’s *any* copper produced whatsoever, then it would be altogether too surprising if there weren’t also quite a lot of radioactive Ni-59 produced; (half-life 101 ky), formed by the reaction
Ni-58 + p -> Cu-59 -> Ni-59 + e+.

A test for Ni-59 that would seem to be conclusive.

A small point – the tables I normally use :
http://www.nndc.bnl.gov/chart/reCenter.jsp?z=29&n=30 or http://atom.kaeri.re.kr/ton/nuc4.html

have Cu-59’s decay mode as electron capture, rather than e+ to Ni-59 with a half life of 81.5s
and Ni-59’s half life is 76,000years not 101,000

[jamesr]

I found this report from a few years ago http://www.enea.it/produzione_scientifica/pdf_volumi/V2008_16Cold_Fusion_Italy.pdf

see page 171-180 for a related experiment.

From this report I seriously doubt their claims.
For example the copper peak in the SEM-EDAX graph (p176) is tiny – look at the number of counts on the scale Poisson error on N counts is sqrt(N) so peak is barely above noise level. To me that graph just looks like the sample was badly cleaned and contaminated from other sources.

The measure flux of 10 neutrons /cm^2/s although higher than background is still very low. All other sources need to be ruled out, as they could easily come from experiments in nearby labs, or just false detections due to electrical noise.

There is no analysis of the isotopic composition of the nickel sample beforehand – there are many isotopes of nickel and ratios vary depending on where it was mined and how it was processed.

I suspect most of the energy is just chemical as in NiMH batteries. They force hydrogen into the metal first (charging it up) then let is discharge.

Above all though fusion needs the nuclei to get close enough to overcome the Coulomb barrier. To do this they must have enough kinetic energy – ie be HOT.

[jamesr]

Just a quick note.. I know you put the link on there, but when citing articles or papers from journals can you include the full reference for example:
I. R. Lindemuth, R. E. Siemon, Am. J. Phys., Vol. 77, No. 5, May 2009

Otherwise its not obvious if the paper is a new one or not.

[jamesr]

Brian H wrote:
When I first started reading, I was looking for the appearance of alpha particles, but no He ions showed up. Didn’t get that (I assume) the alpha wave referred to is the protons plus some deuterium ions(?). Or is it a particular frequency range?

The opening sentence says

Optimal exploitation of the free energy of fusion products, for example, the alpha particles born at 3.5 MeV

Nowhere is the phrase “alpha wave” used. The plasma wave is a collective phenomena of the ions, electrons, and the electric & magnetic fields.

The model, as far as I understand, is based on the fusion born alphas having inital collision(s) with some bulk ions transferring their energy to them. Creating a population of high velocity ions. For simplicity this is modelled as bump-on-tail distribution of protons/deuterons, with the bump at 3MeV directed at an angle to the magnetic field. The system is then evolved to see how the energy is redistributed. They then found

Collective instability gives
rise to electromagnetic field activity in the lower hybrid
(LH) frequency range. The spontaneously excited obliquely
propagating waves undergo Landau damping on resonant
electrons, drawing out an asymmetric tail in the distribution
of electron parallel velocities,which carries a current

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