Rick Nebel comment

Point out news stories, on the net or in mainstream media, related to polywell fusion.

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Robthebob
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Postby Robthebob » Wed Mar 31, 2010 12:17 pm

because it's not yet the greatest achievement in human history. It may not be, we'll have to see.

I dont know man, depends on how you see it. Emc2 will make money if it works, that's a promise, just how much. If they hold the patent for the first design and they know the most about polywell in the world, then yeah, they will make money.
Throwing my life away for this whole Fusion mess.

BenTC
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Postby BenTC » Wed Mar 31, 2010 12:50 pm

icarus wrote:First generation discoverers/developers are always subsumed, out-paced or plain old ripped-off by the wave of financier interests that come along to commercialise successful technologies.

This can be true when inventors try to do it all themselves. If inventors are happy with a small slice of the pie (and its a big pie) then it may be advantageous for the financiers and larger corporations to work with the inventor.
In theory there is no difference between theory and practice, but in practice there is.

TallDave
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Postby TallDave » Wed Mar 31, 2010 3:21 pm

jrvz wrote:I think the most pressing issue is whether Bremsstrahlung prevents a polywell from breaking even (as Todd Rider thinks), or not (as Bussard thought). I.e. loss of energy in x-rays (as opposed to loss of particles). Have any of the results so far addressed this?


I think the experiments so far haven't been really energetic enough to address this question. At ~500W, WB-8 may give us some clues. Rick has said he believes there are trade-offs such that brem can be managed such that we can get large Q values. I'm skeptical this is true for p-B11, but for D-D/D-T it seems very plausible (assuming confinement theory holds up).

Rider also argued ion upscatter would bleed too much energy for IEC devices to achieve Q>1, but Polywells seem to solve that problem nicely.
n*kBolt*Te = B**2/(2*mu0) and B^.25 loss scaling? Or not so much? Hopefully we'll know soon...

KitemanSA
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Postby KitemanSA » Wed Mar 31, 2010 4:48 pm

We keep saying "Rick this" and "Rick that". Rick doesn't own this. Dolly does as far as I can tell. If she says "don't tell" I suspect Rick won't tell.

Has anyone asked Dolly? Is she still active?

ladajo
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Location: North East Coast

Postby ladajo » Wed Mar 31, 2010 5:53 pm

TallDave wrote:
jrvz wrote:I think the most pressing issue is whether Bremsstrahlung prevents a polywell from breaking even (as Todd Rider thinks), or not (as Bussard thought). I.e. loss of energy in x-rays (as opposed to loss of particles). Have any of the results so far addressed this?


I think the experiments so far haven't been really energetic enough to address this question. At ~500W, WB-8 may give us some clues. Rick has said he believes there are trade-offs such that brem can be managed such that we can get large Q values. I'm skeptical this is true for p-B11, but for D-D/D-T it seems very plausible (assuming confinement theory holds up).

Rider also argued ion upscatter would bleed too much energy for IEC devices to achieve Q>1, but Polywells seem to solve that problem nicely.



Rick talked about this before in some detail. I will have to find it again. It was the "Knobs" discussion. I was reminded of it because Rogers used similar terminology in his paper. It is not so hard to do in idea, but until you try, you just don't know.
I will quote an old very drunk friend of mine, "yous guysh jush dohnn unnershhtahnd. WE will shnow when we shnow. OK? You shnow?" It was great speach. Then he fell down and couldn't get up.

ladajo
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Location: North East Coast

Postby ladajo » Thu Apr 01, 2010 5:36 pm

The "Knobs" discussion (aka "Art and Rick, love at first site" :shock: )

from Cosmic Log:
http://cosmiclog.msnbc.msn.com/archive/ ... 36887.aspx
Rnebel responded;
"1. The theory says that you can beat Bremstrahlung, but it's a challenge. The key is to keep the Boron concentration low compared the proton concentration so Z isn’t too bad. You pay for it in power density, but there is an optimum which works. You also gain because the electron energies are low in the high density regions.

2. The size arguments apply for machines where confinement is limited by cross-field diffusion like Tokamaks. They don't apply for electrostatic machines.

3. The Polywell doesn't have any lines of zero field. Take a look at the original papers on the configuration. See :
Bussard R.W., FusionTechnology, Vol. 19, 273, (1991) .
or
Krall N.A., Fusion Technology. Vol. 22, 42 (1992).

Furthermore, one expects adiabatic behavior along the field lines external to the device. Thus, what goes out comes back in. Phase space scattering is small because the density is small external to the device.

4. The machine does not use a bi-modal velocity distribution. We have looked at two-stream in detail, and it is not an issue for this machine. The most definitive treatise on the ions is : L. Chacon, G. H. Miley, D. C. Barnes, D. A. Knoll, Phys. Plasmas 7, 4547 (2000) which concluded partially relaxed ion distributions work just fine. Furthermore, the Polywell doesn’t even require ion convergence to work (unlike most other electrostatic devices). It helps, but it isn’t a requirement.

5. The system doesn’t have grids. It has magnetically insulated coil cases to provide the electrostatic acceleration. That’s what keeps the losses tolerable.

6. The electrostatic potential well is an issue. Maintaining it depends on the detailed particle balance. The “knobs” that affect it are the electron confinement time, the ion confinement time, and the electron injection current. There are methods of controlling all of these knobs."


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