Where's the beef?

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

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Art Carlson
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Where's the beef?

Post by Art Carlson »

In other threads I have explained why, given all that I know about plasma physics, I really, really expect the polywell *not* to work anywhere near well enough to be interesting for power production. Several times I have received responses along the lines that my theoretical ideas must be wrong because the experimental results are so good and substantiate the ideas of Bussard and friends. If the discussion of the theoretical plasma physics doesn't get more interesting, then the experimental results will be the only thing left to look at.

Will someone please help me find the experimental data, so we can discuss it? I haven't swum in these waters as long as you have, so I'm not sure where to look. The most recent and comprehensive report I know of is Bussard's Valencia paper: "The main point of this paper is to present these results of EMC2‘s 20 years of study and research of this approach to clean fusion power." This paper has a stunning lack of experimental results. When you guys say that the polywell has shown good results and good scaling, are you just taking Bussard's and Nebel's word for it, or are there published data somewhere? Of course, the standard in the scientific world is a peer-reviewed paper in a reputable journal, but in a pinch I would also accept a web site, if it is detailed enough.

tonybarry
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Post by tonybarry »

Hello Art,
Bussard produced a report on the final runs of WB-6, which for a time was hosted on the UniWisc website, and is mentioned on Joe Strout's index page. While not exactly a peer-reviewed paper, it might give you some food for thought.

You can now find it on Mark Duncan's excellent fusion pages here ... scroll down to EMC2 Reports abut halfway down the page.

The PDF itself is here.

EDIT:- all these links are dead. Hmmm. PM me.

Regards,
Tony Barry
Last edited by tonybarry on Sun Jul 06, 2008 1:27 pm, edited 1 time in total.

Munchausen
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Post by Munchausen »

This link is dead and has been so for some months:

http://ecow.engr.wisc.edu/cgi-bin/getbi ... nl0107.pdf

tonybarry
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Post by tonybarry »

Indeed, it is dead ... but Mark Duncan's is still good as of a few minutes ago.

Regards,
Tony Barry

Munchausen
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Post by Munchausen »

It is also dead. Just tried it.

tonybarry
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Post by tonybarry »

Hmmm. PM me if you have a need for this file.

Regards,
Tony Barry

Art Carlson
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Post by Art Carlson »

Do you mean this report? Meager. Conclusions, but not an iota of supporting data or references.

(Figured out how to use the URL tags now. Also figured out that Tony meant a different report.)
Last edited by Art Carlson on Sun Jul 06, 2008 1:31 pm, edited 1 time in total.

tonybarry
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Post by tonybarry »

Hello Art,
Check your PMs.


Regards,
Tony Barry

MSimon
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Post by MSimon »

then the experimental results will be the only thing left to look at.
Totally.
Engineering is the art of making what you want from what you can get at a profit.

TallDave
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Post by TallDave »

I think what Art is really looking for -- something rigorous like a paper for peer review -- doesn't exist. Bussard told me last May that he wanted to put one together by the end of the year, but obviously that turned out to be impossible.

The closest we'll likely see is the peer review of the WB-7 results, and that would only be available after the Navy declassifies it, if that ever happens.

In the meantime, while it's non-optimal, I'll just trust that Bussard and Nebel aren't making their data up.

Betruger
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Post by Betruger »

So all that data, that was going to be in that peer review paper, is lost ? If it is, how much of it will be retraceable from WB7 data?

Art Carlson
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Post by Art Carlson »

tonybarry wrote:Hello Art,
Bussard produced a report on the final runs of WB-6, which for a time was hosted on the UniWisc website, and is mentioned on Joe Strout's index page. While not exactly a peer-reviewed paper, it might give you some food for thought.

You can now find it on Mark Duncan's excellent fusion pages here ... scroll down to EMC2 Reports abut halfway down the page.

The PDF itself is here.

EDIT:- all these links are dead. Hmmm. PM me.

Regards,
Tony Barry
I have not given Bussard enough credit for chutzpah. Not only does he have the guts to string together speculations and rules of thumb and call it a theory, he also has the courage to draw far reaching conclusions from minmal, nearly non-existent experimental data and present them with a straight face. I am in awe.

Just a sampling from EMC2 Inertial-Electrostatic Fusion (IEF) Development: Final Successful Tests of WB-6. October/November 2005. Robert W. Bussard and R. Michael Wray. EMC2-0806-04 (rev. 0107):
"If all electron flow were to be governed by the line cusp/corner effects, it would be virtually impossible to maintain high electron densities inside the machine while keeping densities outside low enough to avoid Paschen arcing outside."
I first want to take note of this because it confirms the fatal nature of line cusps.
"Taking fwb and flc as the fractional areas of point cusp and line cusp effects (note that fwb + flc = 1), and summing for parallel channel flow, gives the overall trapping factor as (1/Gmj) = (fwb/Gwb) + (flc/Glc)"
This is brilliant. After explaning that there are two ways that electrons can be lost from the interior, instead of simply adding the loss rates from the two mechanisms, like adding the areas when you have two holes in a bucket, he postulates that some of the electrons are affected by mechanism one and only by that mechanism, while the other electrons are only affected by mechanism two. This allows him to write down a formula that can result in a confinement time longer than the shorter of the two individual times. Add a loss channel and your confinement improves. That's genius.
"Since the key variable in such tests is the electron density at the machine inner edge, and since there was no way available to measure this density directly, it was noted that the density could be determined with precision if the machine could be run at the beta=one condition. ... By sweeping the B field of the machine, the range of plasma/electron “beta” was varied from infinity (at B = 0) to very small values (as B -> kG). In this sweep, it was inevitable that a value of B was reached at which plasma beta was equal to unity. At this condition, the electron density reached its maximum value, as this is the best that can be done by B fields to confine charged particles. This is easy to detect by use of light intensity measurements detecting electron/neutral ionization and subsequent recombination collision effects in the system."
This one floored me. I was worried about whether there was published data on the scaling of confinement time with density, and then I discover that Bussard didn't even measure the density. No interferometry. No Langmuir probes. No spectroscopic methods. No Thomson scattering. Just the assumption of pressure balance and beta equals one. And even that he gets by making a scan of coil current and taking the peak of the photomultiplier signal. That takes real courage.
"Finally, because of the shortness of time and limited available effort, it was only possible to test WB-6 at conditions of interest for fusion for a few tests; four times at electron drive voltages (and consequent well depths) that might produce fusion."
And these four tests produced a grand total of eight neutron counts. I hope that all of you are clear on this. Your hopes for a future without fossil fuels, for cheap and non-radioactive power plants, for interplanetary or interstellar space drives, are based on exactly eight blips of a neutron detector. From these eight counts you are not only deducing the quality of confinement in a small scale device, you are seeing the confirmation of scaling laws that must sustain you over seven orders of magnitude. My hat's off to you. You are every bit as gutsy as Bussard.

Roger
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Post by Roger »

Art Carlson wrote:Your hopes for a future without fossil fuels,.....eight blips of a neutron detector.
We ALL know that.


Which is why we are very happy WB-7 has been built.
I like the p-B11 resonance peak at 50 KV acceleration. In2 years we'll know.

MSimon
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Post by MSimon »

And these four tests produced a grand total of eight neutron counts. I hope that all of you are clear on this. Your hopes for a future without fossil fuels, for cheap and non-radioactive power plants, for interplanetary or interstellar space drives, are based on exactly eight blips of a neutron detector. From these eight counts you are not only deducing the quality of confinement in a small scale device, you are seeing the confirmation of scaling laws that must sustain you over seven orders of magnitude. My hat's off to you. You are every bit as gutsy as Bussard.
Some times things happen outside what "professionals" expect. Take the invention of the airplane. It was not developed by University Professors who knew all the science. It was done by experimentalists. First flight about 150 ft at about 6 to 12 ft off the ground. Not impressive.

Sometimes what "everyone knows" is wrong.

In any case we will have a better idea of the merits of the case in a few months.

I have always been in the "do the experiments" camp. I think it is still a good place to be.
Engineering is the art of making what you want from what you can get at a profit.

Roger
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Post by Roger »

MSimon wrote: I have always been in the "do the experiments" camp. I think it is still a good place to be.
Thats right, best place to be.
I like the p-B11 resonance peak at 50 KV acceleration. In2 years we'll know.

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