[krikkitz]

Tim1 wrote: Would a cold plate, possibly a cylinder just beyond the anode be used to collect most of the boron?

I’d guessing you mean a charged cold plate? Would another charged body inside the chamber mess with the filament formation?

[krikkitz]

Decaborane is highly flammable and self-igniting. Whoever suggested an enriched oxygen environment, that’s a no-go.

Is there any way to deliver the fuel to the tip of the anode rather than filling the reaction chamber? Because decaborane plates out boron anywhere a current touches it, and once deposited, it causes resistance, just filling the vacuum chamber with decaborane is a less than ideal scenario. Depending on how fast the plating builds up on the electrodes, this could seriously interfere with the experiment in very short order, and at $200k per electrode set, you’ll not want to keep changing out the electrodes.

I wonder if there might be a way to deliver the gas through the anode? Since only the outside of the anode needs to conduct the plasma sheath, I’m guessing that there is less need to be careful of plating the inside of the anode. Or, barring that, perhaps a non-conducting tube might direct the decaborane from outside the electrodes to the tip of the anode. If the gas is delivered just where the plasmoid forms by using either of these methods or some other means, there also might be more chance it will be swept up in the filaments and be available for fusion reactions. To maintain the desired vapor pressure in the chamber, perhaps the rest of the chamber could be filled with inert gas prior to delivering the decaborane to the anode tip. In any case, since cleaning the electrodes looks like next to impossible, minimizing the deposition seems like the way to go.

[krikkitz]

Regarding lightbulbs and processes seeking their lowest energy state:

You said, “This is an all-too-common example of misunderstanding in physics. Physical systems seek for their lowest energy state provided that they are isolated. Look e.g. at an old light bulb. Once unplugged, it is switched off, and is isolated from the grid; if it is switched on, it gets warmer, it is not isolated, and its energy content is obviously larger. Note that the bulb is in steady, stable state in both cases; if you shake it gently, it will remain in its original condition, whatever it is, i.e. it relaxes down to its original state after a small perturbation. Both the switched-on and the switched-off bulb are therefore in relaxed state, but the energy content of one state is larger than the energy content of the other state. Should the bulb seek fot its lowest energy state, you’d never be able to switch it on.”

This is the common mistake of many physicists, that all problems must be simple and linear. I did specifically state that the path to the lowest energy state is often “bumpy.” Turn the bulb on. Now turn it off. Now turn it on. Now turn it off. Now turn it on. Now turn it off… Eventually you will reach a point where you can no longer turn it on because the filaments have burned through, i.e., they have reached their current possible lowest energy state. And it will have done so by the quickest possible path, given the parameters of its local system. In your example, you seem to assume that last part does not matter in accounting for a system seeking its lowest energy state, “given the parameters of its local system.” I never said everything seeks it’s lowest energy state by a direct linear path disregarding all other factors! Also, I never said it will always FIND its lowest absolute energy state, only that it seeks it. Energy, after all, is bound into matter, and matter is bound to its local system’s interactions, which constrain it in wonderful ways.

Neither you or I are dim bulbs, Da Vita.

[krikkitz]

Thank you for your additional thoughts on this fascinating topic.

Please allow me to be pedantic for a moment in regarding impossibility of suppressing turbulence, and also allow me to continue as if plasmas are Chaotic for the sake of the debate. Definitions matter because they limit how we may see our way through to solutions. For a well known example, noise in a communications transmission is electrical “turbulence” of the Chaotic type, and there exists no way to suppress this noise. And yet, our communications ability is not only not affected by such noise, but understanding of it in terms of Chaotic processes has allowed us to greatly increase our efficiency of communication across even the noisiest of lines. We essentially are able to do that by ignoring the turbulence and focusing on what lies in between. Just as there are islands of stability in Chaotic systems, there are islands of turbulence. That is exactly the nature of Chaos, turbulence in such systems is bounded at all scales. If we focus only on the noise as an insurmountable problem, we’ll never see the stabilities that also arise across all scales. And thus I dream of Chaos. 🙂

“The mathematical theory of limit cycles is the same theory of chaotic systems (see e.g. Kutznezov’s textbook).”

So there is a Chaotic math characterization of ITER’s emergent problems at least. That is a start. In saying “islands of stability,” I meant to imply those states where the plasma is smoothly producing increasing density in the DPF, rather than the vacuoles of helium that have appeared in the tokamak. As you know, the DPF does not have this helium evacuation problem due to the way in which alpha particles are ejected along the ion beam as the plasmoid collapses, so there is not a direct need to apply the math in the same way. Still, it is encouraging to know work is being done along these lines. Chaos principles work across all scales, and Chaotic processes produce both turbulence and smooth flows within the same system. If plasmas display Chaotic properties, then the system as a whole is indeed Chaotic by definition. So if such vacuoles do appear in the DPF plasma filaments, perhaps they are at such small scales that their effects have not been noticeable in the operation of the DPF so far.

“But such contraction implies no chaos at all. For example, in the Seventies Taylor was able to explain Bohm’s diffusion coefficient in a turbulent (non-chaotic) two-dimensional plasma only.”

By saying “contract to just a few,” I did not mean to imply that there are only two conditions that operate on plasmas in a strong magnetic field. As you obviously know given your response, there are at least three interlocking conditions of sensitivity that are required for a Chaotic system to arise. In plasmas, if they are indeed Chaotic and not simply difficult, those three conditions are likely density, magnetic field, and temperature (i.e., relative energy of the system).

It is fairly obvious that as the density increases the chance for ionic collisions also increases, affecting the localized temperature. But I do not know enough about the subject to say for sure or in depth how this effect of increasing collisions may be coupled to the evolution of the plasma’s magnetic field. At the risk of using a possible straw man argument: Does this operate only in in a one-way manner (increased field gives rise to increased density gives rise to increased collisions)? Or does this operate in the opposite direction (increased collisions gives rise to lower electron energy gives rise to lower magnetic field strength, gives rise to lower density)? If my admittedly basic understanding is correct, then, I suspect that this increase of collisions might give rise to oscillations in the field itself. The question then becomes “At what scale do these oscillations present a problem?” i.e., when do the effects of turbulence arise and interfere with the process?

The difficulty is always at the boundary in Chaotic systems, and so even though in an idealized system, the quantum field effect would characterize the ultimate “island of stability,” getting to that state may be problematic if the system is indeed Chaotic. On the other hand, the good news is that if the system is Chaotic, then this is not the only boundary encountered in plasma in the DPF, and earlier stages of evolution of the filaments of plasma may hold the key to understanding the behavior of the system as a whole as it approaches that all-important transition precisely because Chaotic systems display the same behavior at all scales.

Regarding relaxed states. All of physical reality seeks for it’s lowest energy state. It sometimes has a rather bumpy path to get there, though… 🙂 The principles of least action operate in Chaotic as well as other systems, and thus the appearance of such relaxed states do not negate the possibility of Chaotic action. It’s a matter of scale and coupling of conditions across scales…

Regarding your last paragraph, YES!!! 🙂 I would just add that if the plasma is governed by Chaotic scaling laws, then we need only characterize those laws to understand the operation of the system as a whole. A pipe dream? Could be. Or a mathematician’s dream. I don’t smoke a pipe and I’m no mathematician. I only “see” flows. It’s a gift and a curse. I should have been born with a mathematical mind instead of a spacial one. Math, after all, has a common language, but one I cannot fathom. So I rely heavily on you and others who have that gift of language, M. Da Vita. You can go where I cannot.

[krikkitz]

Thank you for responding to my post, M. Di Vita. Although to my knowledge plasmas have never been characterized formally as Chaotic, they do exhibit some characteristics that led me to think along those lines. For one, they show somewhat smooth transitions to doubling states, i.e., formation of sheaths, which reminds me of bifurcation in Chaotic systems. I understand your point regarding a few versus many degrees of freedom. However, in the presence of an emergent strong magnetic field, those degrees of freedom do essentially contract to just a few. The evidence of this is the behavior of the plasma itself in the DPF, in the way the “instabilities” form. This is order arising from chaos, a hallmark of Chaotic systems. Another characteristic of Chaotic systems is some mechanism of feedback. In the case of the DPF, for one, there is strong feedback from the magnetic fields produced by the plasma in the famous “like likes like” way that moving charges attract each other and organize themselves.

I am certainly not an expert in either Chaos or plasma physics (understatement). I simply know if plasma in the DPF is Chaotic, that efforts to suppress turbulence will not work. What I would really love to see is someone who is well versed in Chaos take a crack at characterizing plasma in the DPF with the view in mind that it just might be Chaotic in nature. If it is and someone could identify an equivalent of a Feigenbaum constant, that could save many headaches and a whole lot of money. It’s worth taking a look.

[krikkitz]

I’ve just read this paper through my subscription to Research Gate and it strikes me once again that of course, plasma dynamics are Chaotic. Di Vita, as with many others, assumes that when you see turbulence, it must be suppressed, but that is not possible in a Chaotic system without destroying the system you seek to preserve. A better approach would be to seek out those islands of stability that always appear in such systems and find a way to exploit them. Identify and exploit. You guys really do need to get in touch with Mitchell Feigenbaum, the mathematician who figured out how to predict these islands of stability in Chaotic systems. I wish I could assist you further, but I am no mathematician (understatement). Mitchell Feigenbaum can be found at the Laboratory of Mathematical Physics at The Rockefeller University. His email is Mitchell.Feigenbaum@rockefeller.edu. Seriously. Good luck.

[krikkitz]

What effects will the differing resistivity/conductivity have on the electric discharge to the plasma when LPP switches first to tungsten and then to Be electrodes? Anyone here conversant with the maths?

[krikkitz]

This may be off base or not an option at present, but have you considered copper plating the tungsten crown?

Edited to say, I wrote the above before reviewing the references you gave, that mention copper plating and then soldering. Hindsight is a dirty nasty biatch. How much disassembly can you do? Enough to set the offending part in a bath of copper sulfate acid solution?

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