Why people are so optimistical to Polywell?

[Joseph Chikva]

If you are considering only space charge and wave based interference, then close collisions may not need to be invoked. But for coulomb scattering scattering, collisions are needed. The point is mostly moot in any case, except for arguments sake. We are arguing over nomenclature, not physics. If you really want to study Potential well possibilities and experimental results you need to research through the Bussard/ EMC2 papers, and also the research with gridded fusors. I suggest you dig through the literature. A couple of places to start follows. Dig through the articles and their bibliography. You will find a lot of more informative and authoritative information than my weak, layman's knowledge and understanding.

http://fsl.ne.uiuc.edu/IEC/Miley_IEEE%2 ... 997%29.pdf

http://fsl.ne.uiuc.edu/IEC/Miley_IEEE%2 ... 997%29.pdf

Dan Tibbets

Ok, thanks.
I will read

[chrismb]

error

Are you one of those really advanced robot answering machines that tends to reiterate answers as further questions, whilst adding in a few random phrases? Who is running your test?

[Joseph Chikva]

error

Are you one of those really advanced robot answering machines that tends to reiterate answers as further questions, whilst adding in a few random phrases? Who is running your test?

I tried to edit exiting text - to add one article.
As you see that my English is bad.
Then the post was doubled. I have deleted one and wrote "error" instead.
And each human is a machine and animal simultaneously.

[93143]

Nor was 93143's "the Navy has re-funded the project and reinstated the gag order."

The reason I said that was that I remembered the assumption we made (was it assumed or stated?) that the publication ban was reinstated along with funding, but neglected to recall the more recent FOIA drama. I probably shouldn't have said it.

However, it occurs to me that preventing publication in scientific journals is not necessarily the same thing as preventing response to a FOIA request...

...oh well. The upshot remains the same - old papers, theorizing in a near data vacuum, a few amateur simulations, a garage project or so, and Kremlinology based on whatever we get from recovery.gov and drive-by sightings of EMC2 with the loading door open...

[KitemanSA]

Slim pickings, isn't it? Sigh!

[TallDave]

As much as I'd like to see the data, I'm taking Rick at his word that it's a combination of the sponsors wanting to keep this quiet (given Rick's comments, it sounds like they're just trying to avoid embarrassing themselves a la Pons), avoid having to deal with flak from the tok crowd, and protect the intellectual property of those at EMC2.

Given the original contract schedule, I'd keep an eye out over the next year for the presence or absence of solicitations that envision WB-8.1 or a 100MW demo reactor being built. That may be the only indication of how "positive" the WB-8 results really were we ever see.

If the project ends with WB-8, the scaling probably did not look as good as hoped (or, possibly the money wasn't there, but even with trillion-dollar budget cuts on the table in the present environment (oil prices, etc) I'd like to think a promising fusion tech would not be abandoned). If we see WB-8.1 but no reactor, the results are probably marginal. A demo reactor contract speaks for itself, of course.

jmho

[KitemanSA]

How would you take a solicitation for yet another intermediate scale machine?

[ladajo]

The only reason I can come up with to do that would be for a superconducter continuous run small scale demonstrator.

It would be a good project to test out things like vacuum management, fuel control technology, magnetic and electrostatic field managment in continuous run mode, possible POPs like testing all prior to going net power demo.

Or, given the current and trending energy environment, just jump to DEMO and work all that out there.

Dunno.

[D Tibbets]

Another sub-scale model could be more economical in terms of cost and time to have a machine that was designed as a testbed for various engineering concerns, direct conversion, etc. I don't know how much room there is with WB8 for assemblies outside the magrid diameter, whether the standoffs are placed optimally, etc. Certainly a full sized machine would have more room, but by the time it was built a sub-scale testbed may have already tested, validated (or invalidated) various concepts, and pointed to needed engineering modifications. Various other concerns might be addressed by separate sub assemblies- such as designing magrid assemblies and their plumbing to determine heat load requirements. Direct conversion assemblies, etc. Sounds like a good prospect for a multigroup approach, University programs, etc.- provided it doesn't become a 20 year employment endeavor.

Dan Tibbets

[Joseph Chikva]

Certainly a full sized machine would have more room, but by the time it was built a sub-scale testbed may have already tested, validated (or invalidated) various concepts,...

As I understand you are talking about WB-8.
But by my opinion nobody could explain yet what did WB-1...WB-7 validate.
Especially a little information on the last WB-7.
I asked you about density of plasma 10^22. That is projected or reached parameter? And did not receive an answer.

[93143]

I asked you about density of plasma 10^22. That is projected or reached parameter? And did not receive an answer.

Projected. This is a high-beta machine, so with a similar magnetic field strength to a tokamak, the density would be much higher.

I don't understand why you're still asking about WB-7 and below, if you've actually done the reading that was recommended to you.

Regarding WB-7 specifically, if I recall correctly, all we know is that it was supposed to validate the neutron rates observed on WB-6 with "improved diagnostics" and more robust construction, and that it "runs like a top", or used to, and that it produced positive but "nuanced" results, and that the results for this machine were looked at by a panel of experts, leading to WB-7.1 which is said to have looked at "confinement behavior with detailed diagnostics", and that this led to an ~$8M contract to build the larger, more powerful WB-8. Also, according to rnebel, the massive cusp losses predicted by Art Carlson have apparently failed to show up in the actual machines.

[KitemanSA]

Regarding WB-7 specifically, if I recall correctly, all we know is that it was supposed to validate the neutron rates observed on WB-6 with "improved diagnostics" and more robust construction, and that it "runs like a top", or used to, and that it produced positive but "nuanced" results, leading to WB-7.1 which is said to have looked at "confinement behavior with detailed diagnostics", and that the results for this machine were looked at by a panel of experts, and that this led to an ~$8M contract to build the larger, more powerful WB-8. Also, according to rnebel, the massive cusp losses predicted by Art Carlson have apparently failed to show up in the actual machines.

Actually, the expert panel reviewed WB7 and based on their comments, WB7.1 was proposed. Since then, I have seen no indication that data on ANY WB has been provided to a panel. Did I miss such indicator?

[93143]

The indicator is that funding jumped by an order of magnitude with a green light given for the next stage.

Still, that's an inference rather than a known fact. I'll change my post (I did say "if I recall correctly", after all...).

[D Tibbets]

Certainly a full sized machine would have more room, but by the time it was built a sub-scale testbed may have already tested, validated (or invalidated) various concepts,...

As I understand you are talking about WB-8.
But by my opinion nobody could explain yet what did WB-1...WB-7 validate.
Especially a little information on the last WB-7.
I asked you about density of plasma 10^22. That is projected or reached parameter? And did not receive an answer.

As 93143 stated, the required features and the machines that addressed them ( to Bussard's satisfaction) have been referenced. More percisely, Bussard's Valencia paper is:

http://www.askmar.com/ConferenceNotes/2 ... 0Paper.pdf

Begining on ~ page 4, he presents the milestones and the machines that addressed them.

As far as density, I think that ~ 10^13 particles / CC was mentioned for WB6. This would be ~ 10^19 particles per cubic meter. This about a thousand fold lower density of what was predicted for a ~ 10T and 3 M diameter machine.
If you consider that the Wiffleball effect allows for a WTF of a few thousand , then the WTF should increase as the cusp hole size is maintained, while the sphere size is increased by a factor of 10X diameter, volume increases by 1000X. Consider a ballon. Poke eight holes in it. Then blow the ballon up to have 1000X larger volume, but keep the holes the same size. Work out the math. . The hole loss area remains unchanged (due to increased B strength), the pressure increased 100X and volume increases 1000 fold and the surface area increased 100X . The 100X pressure would increase the leak flow through the cusps 100X (r^2 loss scaling). But you also have 1000X as much gas contained. So the leak rate/ unit volume would be 1/10th despite the ~ 100X increase in the density and 1000X increase in volume. It is not that simple when you consider fuel burn up before escape, electron recirculation, etc, but it gives a scaling expectation. That Bussard used this example (10 Tesla magnets and 3 meter diameter) allows for this simple comparison- it only took me two years to figure it out ). Of course B and volume can have different ratios based on engineering and other needs, but it shows the scaling over a broad range, provided that things do not change along the way. This is the basic B^4 r^3/ r^2 scaling (remember fusion scales as the density squared). The larger and more powerful WB 8 should go a long way towards answering this question.

PS: Note that I used a 100X increase in density compared to WB6. This would mean a 10^21/M^3 density in a 'WB100' machine. I think Bussard must have assumed that further improvements in the WB6 baesline performance would make up the difference (better recirculation, better vacuum pumping, betteer arc suppresion, etc.).

Dan Tibbets

[Joseph Chikva]

Projected. This is a high-beta machine, so with a similar magnetic field strength to a tokamak, the density would be much higher.

I do not know how correct to use beta in Polywell case. If beta is a relation of kinetic pressure to magnetic pressure. Where is the magnetic pressure in reaction zone?
Frankly, I do not see any possibility for Polywell to reach for so high density. But may be I am wrong - not sure.

I don't understand why you're still asking about WB-7 and below, if you've actually done the reading that was recommended to you.

I have read some recommended papers, some that I found from myself. Question is only on results on base of which the decision on the next stage funding is making.

Regarding WB-7 specifically, if I recall correctly, all we know is that it was supposed to validate the neutron rates observed on WB-6 with "improved diagnostics" and more robust construction, and that it "runs like a top", or used to, and that it produced positive but "nuanced" results, and that the results for this machine were looked at by a panel of experts, leading to WB-7.1 which is said to have looked at "confinement behavior with detailed diagnostics", and that this led to an ~$8M contract to build the larger, more powerful WB-8. Also, according to rnebel, the massive cusp losses predicted by Art Carlson have apparently failed to show up in the actual machines.

Ok, thanks.