Any official news as of late July 2008?

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

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Aero
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Post by Aero »

cuddihy wrote:Aero, all those criteria are valid if the current state of the art after WB-7 is essentially "it may work for net power but still not sure how the scaling will work", but that still would mean Polywells not any closer than a viable commercial tokamok. Also the 3rd criteria would seem to indicate that WB-7 wasn't even going to answer the p-B11 question, that would requires a full-scale (at least net power DD) machine to test.
Hmm -- I don't see it quite that way ... IIRC The objective of WB-7 always was to verify the WB-6 results. I expect that was accomplished. Remember, WB-6 results, although sparce, were very good. I doubt WB-7 results were sparce, since they could "take data all afternoon." And although nuanced, I expect that they adequately confirmed WB-6 results. Remember, both Dr. Bussard wanted, and Dr. Nebel wants to go for net power as a next step. From Dr. Nebel's remarks that I culled above, I am speculating that the review committee determined that proving p-B11 fusion is the next critical research to be undertaken. Someone more knowledgeable of Polywell fusion than I will need to explain just how that should be done as I was under the impression that it was cut and dried after the machine was scaled up. But of course nothing at that level of physics and engineering is ever "cut and dried." :oops:
And the BFR is a lot closer than the Tokamak. According to Dr. Nebel, five years for the BFR, if P-B11 fusion works. What is Tokamak, 40 years? 20 years?
Aero

hanelyp
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Post by hanelyp »

cuddihy wrote:...Also the 3rd criteria would seem to indicate that WB-7 wasn't even going to answer the p-B11 question, that would requires a full-scale (at least net power DD) machine to test.
p-B11 seems to me largely a matter of plasma energy distribution. A device of WB-7 scale could answer that question, though steady state would make the measurements a lot easier. The other leading question, scaling, would need a new machine at a different scale for comparison.

Aero
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Post by Aero »

hanelyp wrote:
cuddihy wrote:...Also the 3rd criteria would seem to indicate that WB-7 wasn't even going to answer the p-B11 question, that would requires a full-scale (at least net power DD) machine to test.
p-B11 seems to me largely a matter of plasma energy distribution. A device of WB-7 scale could answer that question, though steady state would make the measurements a lot easier. The other leading question, scaling, would need a new machine at a different scale for comparison.
Does this mean that a small contract using WB-7 equipment with maybe new and bigger power supplies is the minimum required to prove p-B11 fusion? If so, then that is obviously the next step to take, in my world view. But at some point we need to quit stringing this out serially and take some research steps in parallel as has been thoroughly discussed on other threads.
Aero

IntLibber
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Post by IntLibber »

Aero wrote: Does this mean that a small contract using WB-7 equipment with maybe new and bigger power supplies is the minimum required to prove p-B11 fusion? If so, then that is obviously the next step to take, in my world view. But at some point we need to quit stringing this out serially and take some research steps in parallel as has been thoroughly discussed on other threads.
As I recall from Bussard's Google lecture, WB-6 could only do D-T fusion due to its scale and power limitations. The voltage demands for Proton-B11 fusion were significantly higher, about 5-10 times higher I think, which necessitates a much better power supply system than they had for WB-6, and a larger scale reactor. How much bigger is WB-7 over WB-6? I thought his paper stated the WB-100 scale system was necessary for the B11 process.

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Post by D Tibbets »

My understanding is that the WB-6 only used D-D fuel. It was compared to earier Farnsworth- Hersch type fusers that obtained similar neutron outputs with D-T fuel and at voltages ~10 times greater.

And, simply speaking, I'm guessing that extrapolating fusion rates of various fuels based their crossection is straight forward. But, I wonder if the different masses/ charges of the two fuel elments- H (plus one charge with mass of one)- vs B11 (plus 5 charge with mass of 11) complicates the interactions. The protons would be accelerated to about twice the speed of the boron ions in the same electrostatic field, and the protons would be scattered more from nonfusing collisions due to their smaller mass compared to the boron ions. Is that incorperated into their crossections? Or is expermental data needed to make acurate predictions?


Dan Tibbets
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Barry Kirk
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Post by Barry Kirk »

Not twice the speed. Sure the charge to mass ratio is double so the energy per mass is double, but doubling the energy does not double the speed. Increases it by about 1.41.

I'd have to think about it to figure out what happens to the protons, but I doubt they would end up doubling their energy in even a head on collision.

Tom Ligon
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Post by Tom Ligon »

For purposes of calculating cross sections, in the head-on case you don't double the energy, you quadruple it, if I recall the procedure for the cases I looked at.

This sounds profoundly wrong until you get into the guts of the fusion cross-section data. The cross sections were originally obtained by one moving ion and a stationary target. To calculate the cross section, you have to do a reference frame shift making one ion stationary, one moving at twice the original velocity. The actual basis for fusion cross section is momentum (proportional to the velocity), but the look up values for cross section are kinetic energy (typically the accerating voltage of the device that measured the original values). Since KE goes as velocity squared, squaring 2 V gives 4x the KE. To force the correct kinetic energy for a valid lookup, you assume 4x the KE of either particle relative to the center of mass of the IEC machine.

You have to work thru it before you believe it. You are not actually quadrupling energy, you just claim to be in the calculation.

Barry Kirk
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Post by Barry Kirk »

That actually makes sense...

Hmmm.... One more thing to add to the efficiency of IEC

93143
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Post by 93143 »

I was wondering about that... solid targets, that makes sense.

Sounds like the applied potentials for p-11B could actually be quite low, particularly if you were to aim for the resonance peak...

D Tibbets
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Post by D Tibbets »

So, if I'm following correctly, at least for the first collision the crossection is directly proportional to the reaction rate, and since the IEC fusers are essentially opposing beam devices they have a distint advantage over Tokamak type devices that depend on random collisions within the hot plasma to direct potentially fusing nuclei twards each other.

And, to drift even further off topic- since there are two different species in p- 11B fueled reacters, will it effect efforts to maniplate flow such as with POPS. Will frequencies need to match resonances of both the P and 11B, or will the mixture act as a homogenous medium? Will one or the other tend to loose more energy to the other and accumulate more in the center, effecting the vertual anode? Will enough 11B nuclei accumulate in the center to make a minature black hole and consume the Earth? :roll:

Dan Tibbets
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MSimon
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Post by MSimon »

93143 wrote:I was wondering about that... solid targets, that makes sense.

Sounds like the applied potentials for p-11B could actually be quite low, particularly if you were to aim for the resonance peak...
The resonance peak is at about 50 KV drive voltage nominal. On the order of 65 KV with well losses.

The broad peak is at around 200 KV drive. Say 220 to 250 KV actual drive.

Power gain will be higher at the 50 KV resonance. Control will be easier at 200 KV.
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MSimon
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Post by MSimon »

D Tibbets wrote:So, if I'm following correctly, at least for the first collision the crossection is directly proportional to the reaction rate, and since the IEC fusers are essentially opposing beam devices they have a distint advantage over Tokamak type devices that depend on random collisions within the hot plasma to direct potentially fusing nuclei twards each other.

And, to drift even further off topic- since there are two different species in p- 11B fueled reacters, will it effect efforts to maniplate flow such as with POPS. Will frequencies need to match resonances of both the P and 11B, or will the mixture act as a homogenous medium? Will one or the other tend to loose more energy to the other and accumulate more in the center, effecting the vertual anode? Will enough 11B nuclei accumulate in the center to make a minature black hole and consume the Earth? :roll:

Dan Tibbets
With POPS you pick the species. I expect there will be some interaction depending on the Q of the resonances.
Engineering is the art of making what you want from what you can get at a profit.

Maui
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Post by Maui »

IntLibber wrote: Well Obama is anti-nuclear-anything, so its a waste of time to try there, the political left is almost unanimously against any kind of nuclear power (other than the few intelligent greens who have admitted nuke is the only solution to saving the environment).
Oh, come on. I hate our tendencies to assume the worst from the other side. All that Obama has said is that the problem of nuclear waste needs to be solved before building new fission plants. What is unreasonable about that?

And who --on either side-- thinks that nuclear power is the only option? Certainly, it could be a significant piece, but I bet all but a few people here even realize nuclear power can not account for all of the solution, especially in the short term.

If you think McCain would be better to solve the energy problem, fine. But don't buy into the B.S. of the political henchmen, okay?

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Post by MSimon »

Maui wrote:
IntLibber wrote: Well Obama is anti-nuclear-anything, so its a waste of time to try there, the political left is almost unanimously against any kind of nuclear power (other than the few intelligent greens who have admitted nuke is the only solution to saving the environment).
Oh, come on. I hate our tendencies to assume the worst from the other side. All that Obama has said is that the problem of nuclear waste needs to be solved before building new fission plants. What is unreasonable about that?

And who --on either side-- thinks that nuclear power is the only option? Certainly, it could be a significant piece, but I bet all but a few people here even realize nuclear power can not account for all of the solution, especially in the short term.

If you think McCain would be better to solve the energy problem, fine. But don't buy into the B.S. of the political henchmen, okay?
Who are O's constituents? The drill now pro nuke folks? Or the no drill, no nukes people?
Engineering is the art of making what you want from what you can get at a profit.

JLawson
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Post by JLawson »

Seems to me they're BANANAs. "Build Absolutely Nothing Anywhere Near Anything". So to answer the question - they're no-nuke, no-drill folks, who have both an inherent distrust in any technology they don't understand, and an aversion to learning enough to understand anything they don't already know.

The safe handling of nuclear waste isn't magic, however - technically pretty much all the problems have been solved. You encase the really long-lived stuff in glass and bury it in Yucca Mountain. The longer the half-life, the less dangerous it is, so after a thousand years or so it's essentially harmless. Take the really hot stuff, which has a short half-life anyway, put it in thick-wall stainless steel, glass-lined casks and pour in tar or something to keep the stuff from shifting. Bury in dry place. By the time the steel has rusted away, the glass has eroded off, and the tar weathered away, it should be so much harmless scrap.

But those are technical solutions, and the left has a great adversion to some forms of technology. If the Polywell works out, I'm betting they'll do their damndest to block any sort of Polywell power plant construction, because it's new and unproven technology.
When opinion and reality conflict - guess which one is going to win in the long run.

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