Why people are so optimistical to Polywell?

[Giorgio]

I think we've made breakthrough progress here =]

I am not yet so sure

[Joseph Chikva]

Are you sure that distribution in Polywell is obligatory Maxwellian? Or you also have invented a new distribution and only use an old name?

You seem not to get it.
We are not sure about anything. The same way you cannot be sure about your model working!
Until proper experiments will be done all we can do is consider the model and try to understand why it should work or should not work.

To do this you need to use the same terminology we are using.
I do not count the times I had harsh discussions here with other people because we define a word in 2 different way.
Anyhow, these are the terms that are used here, so either you stick to them or you will never be able to understand and make the other understand your point of view.

Thanks, I have already understood that temperature is not temperature.
Thermilizing is Maxwllian. Maxwellian distribution that has been calculated in case of some restrictions (e.g. all collisions are elastic and not sure but think at absence of any field acting on particles) etc.
The next step I think will be the invention of a new physics laws. And then living in a new world (virtual reality) where those laws work. Electricity in that world will be produced only by Polywell.
Thanks, I am a little bit disappointed in discussion level here.
Good luck you all.

[cuddihy]

Thanks, I have already understood that temperature is not temperature.
Thermilizing is Maxwllian. Maxwellian distribution that has been calculated in case of some restrictions (e.g. all collisions are elastic and not sure but think at absence of any field acting on particles) etc.
The next step I think will be the invention of a new physics laws. And then living in a new world (virtual reality) where those laws work. Electricity in that world will be produced only by Polywell.
Thanks, I am a little bit disappointed in discussion level here.
Good luck you all.

Same to you. But do yourself a favor and check back in 6-9 months. You may find that assumptions you have made about how all plasmas behave are, in fact wrong, because they are only applicable to certain conditions that a polywell does not meet.

[chrismb]

Thanks, I am a little bit disappointed in discussion level here.
Good luck you all.

That's because you have not applied yourself to understanding the difference between 'thermal plasmas' and 'generally cold, locally hot' devices. Polywell is [ideally, though probably only for a few milliseconds] the latter, whereas you have been talking about the former and have not taken any hints to expand your understanding.

Thanks for coming on by and trying to teach us all that you don't know.

[D Tibbets]

....
First

TOKAMAKs developers do not hope on 90% burning-off fuel. But on much less. In Polywell and in other beam devices as well by idea the burning-off should be more. But not 100%. Because in reaction zone gradually will decrease the density of reacting nucleii together with appearance of other charged particles - products of reaction.
Second
The temperature in TOKAMAKs not 5keV but 10 keV reached in latest versions and 15keV projected for ITER.
Third
There is one more difference between beam method (using coherent motion of particles for overcoming barrier) and thermal method: for beam we should spend 100% required for fusion KE before reaction. In thermal methods only high energetic tail of distribution can work initially. That is "ignition". Then by idea self-heating at the expense of fusion. It is not advantage or disadvantage but only the feature of method.
Fourth
I am repeating. Till now I could not see any mechanism allowing to avoid thermalization in Polywell. But thermalization will occur obligatory. As together with each fusion event you will get thousands elastic collisions events as well. So, If you have not any dissipating mechanism better if together with mechanism returning the scattered particle to the right direction, sorry. Because you will not can save your so lovely "mono-energetism"

1St, I never said that I expected a Tokamak to burn up 90% of the fuel. I said 90% of the fusion that does occur will result from those ions at the high end thermal tail of the plasma. This is an example, please do not think that I am implying an accurate quantitative profile of fusion rates vs temperature.

2nd, I gave an example for Tokamak temperatures. Obvously, a considerable effort has been expended to boost the operating temperature of Tokamaks. I even included a example where the Tokamak had a 20 KeV temperature, in excess of your expectations.. The point was not only the average temperature reached, but also the thermal spread about that temperature.

3rd, Percisely. Tokamaks are thermal machines that depend on ignition to provide the nessisary thermal temperature against losses.
A Polywell is a power amplifier. It does not use ignition. In fact, ignition is bad as that implies that the high energy fusion ions are thermalizing within the plasma. If Coulomb collisionality and dwell times allow for high energy fusion ions thermalization, then all of the lower energy fuel ions would also be quickly thermalizing- which is not desired. Thinking about it, this may be one reason that A. Carlson thought that such high potential wells was needed (several million electron volts- because he may have assumed that the multiMeV fusion ions were contributing to the overal ion population thermalized mix.
But, fusion ions in a Polywell are expected to give up almost none of their energy to the plasma before they escape through a cusp.They are expected to make ~ 1000 passes (due to the Wiffleball traping factor- not the potential well which is of course way too weak to effect these ions much). Wven with a few thousand passes the distance traveled will only be a few thousand meters, and the MFP at >~3 MeV energies is in the tens of thousand Meter range. Also, the fusion ions would not maintain confluence for long so they would not have as much concentrating effect in the core as the fuel ions are expected to have. I can explain my reasoning on this.if you wish.
As you suggested, all, 100% of the ion energy comes from the potential well. There is no (ideally) heating from scattering collisions. There is some thermal spread ongoing but no needed boosting of the temperature. And, this thermal spread is minimal to moderate depending on machine size, operating density, effectiveness ot 'annealing', etc. Also, just as with electrons there is a mechanism for preferentially removing runaway upscattered ions, just as there is for electrons.

4th, Yes Coulomb scattering collisions will always exceed fusion collisions. But, not nessisarily by thousands. In D-T reactors, at ~ 100 KeV Coulomb collisions only exceed fusion collisions by ~ 10X. In D-D reactors this ratio at 100 KeV would be closer to ~ 100-1000, but not much more. Again, mechanism to prevent, or at least retard the thermalization process is nessisary. I have discussed two of the methods, and touched on a third.

You also seem to be stuck on beam- beam or beam- target fusion concepts where there is only one (or a few) chances for fusion collisions befor the beam energy is dispersed or absorbed into the target. While the Polywell is ideally a beam - beam machine. It is definity not a coherent* two opposing beam machine. The spherical geometry and the potential well means that basically you do not care if there is dominate Coulomb scattering over fusion ( thermalization concerns are present, but cooling concerns are negligible). The ions will scatter, but due to the potential well and the spherical geometry they (almost) always return for another try. This is obvous for anybody who has studied gridded fusors. . The difference with the Polywell is that the ions might have many thousands, or even millions of passes, where gridded fusors at best only ave <100 tries, and beam- beam, or beam- solid target systems only get essentially a few tries. before they lose their energy.

Comparing Tokamak physics to claimed Polywell physics is of course perfectly legitimate, but using Tokamak assumptions and applying them to Polywells is like comparing a vulture to a hummingbird. They both obey certain rules, but they achieve and maintain flight in different ways.

*POPS effects might chang this somewhat, but again in a spherical framework, not a collumated beam arrangement.
Dan Tibbets

[Joseph Chikva]

Thanks for coming on by and trying to teach us all that you don't know.

Oh, I have forgotten to say goodbye personally to you.
Oppenheimer-Fisher reaction (birth of hydrogen nucleus with three neutrons in d+T case ) was magnificent. Thanks again.

[Giorgio]

Thanks, I am a little bit disappointed in discussion level here.
Good luck you all.

And I am disappointed that you showed such a close attitude.
Anyhow, good luck to you too with your plans.

[MSimon]

Maybe we should start with what thermalization means in the Polywell context.

We have an electron (a bunch of them actually). Because of the E field they can have KE or PE. If you bunch them together where the KE is lowest they will thermalize at some low KE. For instance 100 eV. Then for this mass of particles once they have regained their KE (say 10 KeV) they have an energy for any particular particle of 10KeV +/- 100 eV.

Does the device work that way? So far there are indications but no definitive proof. If that mechanism or something similar is not in evidence the device will not work.

The particle lifetime in the device must be long and the particles must remain mono-energetic. The experiment is to discern if those conditions are evidenced and if they can lead to a practical device.

[93143]

Coherent vs. thermal
Do you know something else?
I do not.

I do. That's why I brought up the shock layer example. Entropy has a maximum partway through the shock, and then declines for the rest of it. The gas inside a shock wave is not in local thermodynamic equilibrium, so the second law of thermodynamics does not apply to its internal processes - only to the end states.

And here's the problem - you are acting like an expert declaiming on a well-characterized phenomenon, when in fact (a) you are not an expert in this field, and (b) a Polywell plasma is not a well-characterized phenomenon, at least not publicly. Even plasma physicists, which you have admitted you aren't, generally have trouble with this configuration.

The main reason we're optimistic about Polywell is that the information we've seen regarding the ongoing experiments indicates that it's working.

[MSimon]

Joseph,

chrismb is one of the biggest sceptics of Polywell. Yet he understands it deeply and his criticism is based on his understanding (and certain exaggerations IMO but that is besides the point). You don't even understand what you are criticizing. And you resent to the point of abandoning the effort your failure.

This is hard stuff - despite the apparent simplicity. Toks are easy by comparison. It took me about six months of hard effort and continuous study to get it. And I was lucky enough that Tom Ligon took the time to tutor me (and any one else near by - read the old thread at NASA Spaceflight - you can follow my progress - also I blogged it at IEC Fusion Technology). I did have the advantage over you. I wanted to learn.

[KitemanSA]

Are you sure that distribution in Polywell is obligatory Maxwellian?

Actually, I am saying the opposite. Polywell is HOPED to be NON-Maxwellian (aka mono-energetic).

[Joseph Chikva]

Joseph,

chrismb is one of the biggest sceptics of Polywell. Yet he understands it deeply and his criticism is based on his understanding (and certain exaggerations IMO but that is besides the point). You don't even understand what you are criticizing. And you resent to the point of abandoning the effort your failure.

This is hard stuff - despite the apparent simplicity. Toks are easy by comparison. It took me about six months of hard effort and continuous study to get it. And I was lucky enough that Tom Ligon took the time to tutor me (and any one else near by - read the old thread at NASA Spaceflight - you can follow my progress - also I blogged it at IEC Fusion Technology). I did have the advantage over you. I wanted to learn.

Thanks, and I wish you to have always advantages and success.
I wanted to learn too but unlike you my "teachers" here were people who mix temperature and velocity definitions, who do not understand that when they mention the thermalization time of milliseconds, that time is highly depends on density, which as I understand should be increased on 3 orders.

You learned from Tom Ligon and what I could learn from e.g. very respectful chrismb, who declares that in colliding beams Oppenheimer-Phillips reactions "stripping" will occur.
For note:
O-P stripping
D(2)+X(A)=p+X(A+1)
So,
• for D+T reaction with birth of hydrogen nucleus with 3!!! neutrons
• for D+He3 that is a target reaction (chris said "you will have high energy particle instead of fusion" when my target is namely to get those high energy particles )
• for p+B11 I do not know what may be stripped here? If proton – as I remember I did not propose to use hadron collider , if B11 - yes, that should be "stripped" as we should get 3 alpha-particles.

But nonetheless I have learned till some non-zero level of understanding how Polywell should work and have some vision on it and not in 6 months but in a few days.
Good luck.

[MSimon]

I wanted to learn too but unlike you my "teachers" here were people who mix temperature and velocity definitions

Temperature = average velocity of particles (assuming identical compositions).

Temperature can also be expressed as average particle energy.

There is nothing wrong with your teachers. It is your problem. Of course thermo is hard. One of the hardest. Nuke Power School washed out more students with thermo class than any other.

Evidently you missed bits. If you ever took (or studied on your own) thermo.

1 eV ~= 11,605 deg K

http://iecfusiontech.blogspot.com/2007/ ... tants.html

[Joseph Chikva]

I wanted to learn too but unlike you my "teachers" here were people who mix temperature and velocity definitions

Temperature = average velocity of particles (assuming identical compositions).

Temperature can also be expressed as average particle energy.

There is nothing wrong with your teachers. It is your problem. Of course thermo is hard. One of the hardest. Nuke Power School washed out more students with thermo class than any other.

Evidently you missed bits. If you ever took (or studied on your own) thermo.

1 eV ~= 11,605 deg K

http://iecfusiontech.blogspot.com/2007/ ... tants.html

I see you missed some bits from yourselves
As with the same success you can express eV also in kg
As 1 eV = ~17.8E-37 kg
But without correct definition that is very nonsense action I have shown above and also expressing coherent motion energy as "temperature"

So, following your logic when you call fast moving streams "hot" with the same success you can call they "heavy"

For high energy beams there is a definition of multi-dimensional phase volume (coordinates x thermal momentums) and nobody mixes those thermal momentums that really may be expressed as temperature and coherent motion energies. The temperature in those beams may be equal to a few eV and coherent motion energy - giga and may be tera-eVs.

[93143]

The idea of "temperature" in a fusion reactor refers to how fast the ions can be expected to smash into each other. Whether you have a converging/diverging beamlike energy distribution or a wide thermal spread, the upshot is that the "temperature" in eV determines how likely fusion is. (Depending on the distribution, of course, but that's not really an operating parameter; it depends on the nature of the device.)

The (expected) more-or-less beamlike energy distribution in a Polywell serves the same purpose, qualitatively, as the nearly Maxwellian distribution in a tokamak, so it gets described by the same words. There's no need to be so inflexible about it; English doesn't work that way.