WB-7 details?
WB-7 details?
Are there any details of WB-7 that can be shared? Is it a 100% clone of WB-6? Is it the same size? Does it have pulsed operation or is it continuous? What are the voltage / current levels? Did they make the coils more rugged vs WB-6?
AS far as I know, WB7 is more robust then WB6, but the same size. I'm guessing the goal is to duplicate the WB6 results, with a device that is up to the task of repeated test runs for any critics viewing.
I'll bet there will be critics assailing the neutron counts. SO Having a robust device that can be run and re run reliably allows Dr Nebel to use different detector schemes to satisfy the harshest of critics.
I cant wait for summer... >sigh<
I'll bet there will be critics assailing the neutron counts. SO Having a robust device that can be run and re run reliably allows Dr Nebel to use different detector schemes to satisfy the harshest of critics.
I cant wait for summer... >sigh<
I like the p-B11 resonance peak at 50 KV acceleration. In2 years we'll know.
Ideally WB7 will satisfy the "harshest of critics." In reality, what are the harshest criticisms that could be levelled?
If we assume (for the sake of argument) that WB7 is actually doing the same rate of fusion that Dr. Bussard thought WB6 was doing, is it the best the critics can do to resurrect old ghosts like Farnsworth's fake neutron counts? And of course, science is far enough advanced now to shield outside neutron sources.
Could alpha particles also be measured?
If we assume (for the sake of argument) that WB7 is actually doing the same rate of fusion that Dr. Bussard thought WB6 was doing, is it the best the critics can do to resurrect old ghosts like Farnsworth's fake neutron counts? And of course, science is far enough advanced now to shield outside neutron sources.
Could alpha particles also be measured?
The critics will bring up Rider and Nevins. Rider said it can't work because of brehmsstrahlung losses (unless you could efficiently recirculate them into angular momentum for the ions), ion upscatter (thermalization), and plasma density issues (Coulomb cross-section >> angular inertia cross-section). Nevins said that even if you neglect these issues, Q is limited to 0.091, and 0.21 for the most optimistic case (D-T fusion) because of ion energy diffusion in the core (and he claims not to be even considering the energy needed to maintain the potential well).
Nevins left a crack open at the end of his paper (Phys. Plasmas, Vol. 2, No. 10, Oct. 1995, "Can inertial electrostatic confinement work beyond the ion-ion collisional time scale?"):
Nevins left a crack open at the end of his paper (Phys. Plasmas, Vol. 2, No. 10, Oct. 1995, "Can inertial electrostatic confinement work beyond the ion-ion collisional time scale?"):
In November 2000, that same journal published a paper by L. Chacon, G.H. Miley, D.C. Barnes, and D.A. Knoll that did exactly what Nevins suggested ("Energy gain calculations in Penning fusion system susing a bounce-averaged Fokker-Planck model"), and claimed to discover that Q>100 should be possible for large well depths. The one problem with their analysis -- and it's a big one -- is that they expressly ignore ion-electron interactions and assume a single ion species. This latter paper, from what I can tell, is the reed that a lot of this effort is clinging to, considering the publishing embargo Bussard was under for the last decade.This analysis is based on a particular model ion distribution function. While the reactor operating point has been optimized over the parameters of this model, it is possible that a more attractive power balance could be obtained by further optimization of the form of the ion distribution function. A serious effort to perform such an optimization would
require the development of a bounce-averaged Fokker-Planck code in (e, L2) space. However, it seems most unlikely that such optimization will increase Q by the factor of 100 (or ~50 if hard core potentials can be maintained) required to achieve an acceptable recirculating power fraction for an economic power plant. Hence, we conclude that inertial electrostatic confinement shows little promise as a basis for the development of commercial electrical power plants.
Actually the reed that this all hangs on is experimental results.scareduck wrote:In November 2000, that same journal published a paper by L. Chacon, G.H. Miley, D.C. Barnes, and D.A. Knoll that did exactly what Nevins suggested ("Energy gain calculations in Penning fusion system susing a bounce-averaged Fokker-Planck model"), and claimed to discover that Q>100 should be possible for large well depths. The one problem with their analysis -- and it's a big one -- is that they expressly ignore ion-electron interactions and assume a single ion species. This latter paper, from what I can tell, is the reed that a lot of this effort is clinging to, considering the publishing embargo Bussard was under for the last decade.
At this time it is my estimation that except for electron losses no one knows what the hell is going on in a Bussard Reactor.
The next step is to build bigger pulsed reactors and a continuous operation (10s of seconds to 100s of minutes) test reactor so that there is more time for measurement.
Engineering is the art of making what you want from what you can get at a profit.
That may be so, but I still find it disturbing when one of the seminal papers in this area "cheats" to get an interesting result (Q>>1). I agree with you that they need to put more money into this thing to find out whether there's something real here.MSimon wrote:Actually the reed that this all hangs on is experimental results.
Scareduck,
It is my estimation that none of the calculations done so far has any merit what so ever except as a diagnostic. And limited value for that.
Beams form, the beams bunch. AFAIK the MIT guys were the first to show this mathematically. When I pointed out the MIT paper it caused a small sensation in the WB-7 "inner circle". This is despite the fact that they have a spectrum analyzer. No doubt the lack of continuous operation has limited the amount of data that could be collected.
At this point in time everyone doing calculations has compromised something to make the calculations tractable. No one at this time knows what to leave out and what to include because we do not have a continuously operating reactor to compare calculations with.
Right now this is like the movie business "Nobody knows nutin".
I'd like to get WB-7x up as soon as possible after we get the "go". Because without continuous operation of a test reactor we are groping in the dark.
There is a reason I call WB-7x The Great Convincer.
It is my estimation that none of the calculations done so far has any merit what so ever except as a diagnostic. And limited value for that.
Beams form, the beams bunch. AFAIK the MIT guys were the first to show this mathematically. When I pointed out the MIT paper it caused a small sensation in the WB-7 "inner circle". This is despite the fact that they have a spectrum analyzer. No doubt the lack of continuous operation has limited the amount of data that could be collected.
At this point in time everyone doing calculations has compromised something to make the calculations tractable. No one at this time knows what to leave out and what to include because we do not have a continuously operating reactor to compare calculations with.
Right now this is like the movie business "Nobody knows nutin".
I'd like to get WB-7x up as soon as possible after we get the "go". Because without continuous operation of a test reactor we are groping in the dark.
There is a reason I call WB-7x The Great Convincer.
Engineering is the art of making what you want from what you can get at a profit.
from:Numerical solution of stochastic differential equations and especially stochastic partial differential equations is a young field relatively speaking. Almost all algorithms that are used for the solution of ordinary differential equations will work very poorly for SDEs, having very poor numerical convergence.
http://en.wikipedia.org/wiki/Stochastic ... l_equation
So there you have it even Fokker-Planck is no panacea.
Once we get a reactor operating we can look at results of the math and look at where the math needs to be refined. Until then I wouldn't depend on the math for anything.
More from the wiki:
Note that the Schrödinger equations for anything more difficult than than an electron circling a proton are almost impossible to solve.In physics, the main method of solution is to find the probability distribution function as a function of time using the equivalent Fokker-Planck equation (FPE). The Fokker-Planck equation is a deterministic partial differential equation. It tells how the probability distribution function evolves in time similarly to how the Schrödinger equation gives the time evolution of the quantum wave function or the diffusion equation gives the time evolution of chemical concentration. Alternatively numerical solutions can be obtained by Monte Carlo simulation. Other techniques include the path integration that draws on the analogy between statistical physics and quantum mechanics (for example, the Fokker-Planck equation can be transformed into the Schrödinger equation by rescaling a few variables) or by writing down ordinary differential equations for the statistical moments of the probability distribution function.
What happens when you have 1E20 electrons circling 1E20 Deuterium ions? Interacting with external electrostatic and magnetic fields? And all this swishing around interacting with each other and with the fields.
What we need is a quantum computer. About 10 to 15 ft across. Capable of operation for minutes at a time. Hours better.
Engineering is the art of making what you want from what you can get at a profit.
Does this then mean that the Virtual Polywell simulations will be unable to make simplifying assumptions (so, for me, the non-physicist, unable to treat the electrons as a fluid and the plasma as a fluid) -- because doing individual particle simulations is hard, but would be fun.MSimon wrote:from:Numerical solution of stochastic differential equations and especially stochastic partial differential equations is a young field relatively speaking. Almost all algorithms that are used for the solution of ordinary differential equations will work very poorly for SDEs, having very poor numerical convergence.
http://en.wikipedia.org/wiki/Stochastic ... l_equation
Do the stochastic processes at the electron level have a significant impact on upscatter, thermalization, brehmsstrahlung losses, or plasma beams (forming or bunching)?
(With the disclaimer that I'm still just getting my mind around what each of those are...)
MSimon,
Spot on about WB-7x. Having a device that can run for say..... 10 to 15 minutes at a clip, and can be re-run every week or so, would allow for "Tours". Different groups (Congresspersons, Scientists from esteemed institutions) could be invited to measure, probe & poke to their hearts content.
Even WB-7 should allow for repeated tests for different guests. But 15 minute runs by WB-7x gives ample time for some interesting measurements to be made that can't be made with WB-7.
The one thing about WB-7x cant do, is give us a hint on scaling, I would advocate for a device bigger than WB-7, that is still somewhat cheap but can give us a hint on the scaling issue. Whether a device double the size of WB-7 can give us a hint on scaling I don't know... But if WB-7 costs 1.8 million, would a 2 ft WB-8 cost 3.6 million ? And give us scaling data ? Even in pulse mode....
Can we run a 2 ft Polywell in pulse mode and get worthwhile data on scaling, comparing to the 1 ft WB-7 ?
Or does this scaling question need to settled by building a WB-7x @ one foot, and then a WB-8x at 2 ft.
Which brings me back to Dr Bussard saying the 3 meter concept needs to built, if built to Convincer specs, a 3 meter device running for 15 minutes would settle scaling and a bunch of other stuff.
>sigh<
Spot on about WB-7x. Having a device that can run for say..... 10 to 15 minutes at a clip, and can be re-run every week or so, would allow for "Tours". Different groups (Congresspersons, Scientists from esteemed institutions) could be invited to measure, probe & poke to their hearts content.
Even WB-7 should allow for repeated tests for different guests. But 15 minute runs by WB-7x gives ample time for some interesting measurements to be made that can't be made with WB-7.
The one thing about WB-7x cant do, is give us a hint on scaling, I would advocate for a device bigger than WB-7, that is still somewhat cheap but can give us a hint on the scaling issue. Whether a device double the size of WB-7 can give us a hint on scaling I don't know... But if WB-7 costs 1.8 million, would a 2 ft WB-8 cost 3.6 million ? And give us scaling data ? Even in pulse mode....
Can we run a 2 ft Polywell in pulse mode and get worthwhile data on scaling, comparing to the 1 ft WB-7 ?
Or does this scaling question need to settled by building a WB-7x @ one foot, and then a WB-8x at 2 ft.
Which brings me back to Dr Bussard saying the 3 meter concept needs to built, if built to Convincer specs, a 3 meter device running for 15 minutes would settle scaling and a bunch of other stuff.
>sigh<
I like the p-B11 resonance peak at 50 KV acceleration. In2 years we'll know.
There is no way at this time to know what the proper simplifying assumptions are.dch24 wrote:Does this then mean that the Virtual Polywell simulations will be unable to make simplifying assumptions (so, for me, the non-physicist, unable to treat the electrons as a fluid and the plasma as a fluid) -- because doing individual particle simulations is hard, but would be fun.
It may be, when we know enough, that all this boils down to 5 or 6 algebraic equations and a couple of rules of thumb.
Last edited by MSimon on Thu Jan 24, 2008 8:06 pm, edited 1 time in total.
Engineering is the art of making what you want from what you can get at a profit.
Roger,
The cost driver for continuous operation is power supplies. My WAG on WB-7x costs were around $10 to $15 million.
You really wouldn't want to order a scaled up model without proof that WB-7x produces results. You might start designing it while WB-7x does its experimental runs.
Of course if Congress supplies funds generously then why not build the two in tandem?
The cost driver for continuous operation is power supplies. My WAG on WB-7x costs were around $10 to $15 million.
You really wouldn't want to order a scaled up model without proof that WB-7x produces results. You might start designing it while WB-7x does its experimental runs.
Of course if Congress supplies funds generously then why not build the two in tandem?
Engineering is the art of making what you want from what you can get at a profit.
MSimon, go back a second.
I see 2 separate issues.
1) Scaling
2) Continuous operation on the order of 10 to 15 minutes.
Can scaling be dealt with by Dr Nebel building a WB-8, twice the size of WB-7? In other words can scaling issues be dealt with by building a 1 footer and a 2 footer, that are operating pulsed, as in WB-6 ?
I guess yes, as a 2 ft WB-8 should generate neutrons at a scaled up rate compared to the 1 ft WB-7.
If not, then scalling issues could be dealt with by comparing continuous running (10 to 15 minutes) of a 1 ft WB-7x to a 2 ft WB-8x.
As long as Bussards scaling theory is ballpark correct, I feel good. AS in... maybe the 3 meter size for 500 MW concept, ends up being 3.5 meters. WHo would give a crap at that point..... right ?
I see 2 separate issues.
1) Scaling
2) Continuous operation on the order of 10 to 15 minutes.
Can scaling be dealt with by Dr Nebel building a WB-8, twice the size of WB-7? In other words can scaling issues be dealt with by building a 1 footer and a 2 footer, that are operating pulsed, as in WB-6 ?
I guess yes, as a 2 ft WB-8 should generate neutrons at a scaled up rate compared to the 1 ft WB-7.
If not, then scalling issues could be dealt with by comparing continuous running (10 to 15 minutes) of a 1 ft WB-7x to a 2 ft WB-8x.
As long as Bussards scaling theory is ballpark correct, I feel good. AS in... maybe the 3 meter size for 500 MW concept, ends up being 3.5 meters. WHo would give a crap at that point..... right ?
I like the p-B11 resonance peak at 50 KV acceleration. In2 years we'll know.
Roger,
I really think you have to prove it operates the same in continuous operation as it does in pulsed mode. WB-7x would do that.
Then go with a 10 m (total) dia pulsed WB-100 for scaling proof.
Or a 2 ft WB-8x might be good too.
Of course I have no idea what the actual path should be. Dr. Nebel might have some useful ideas on that. When he gets some free time.
I really think you have to prove it operates the same in continuous operation as it does in pulsed mode. WB-7x would do that.
Then go with a 10 m (total) dia pulsed WB-100 for scaling proof.
Or a 2 ft WB-8x might be good too.
Of course I have no idea what the actual path should be. Dr. Nebel might have some useful ideas on that. When he gets some free time.
Engineering is the art of making what you want from what you can get at a profit.
Yes..ish. I mean, rx2 tells you something about scaling... but the fusion itself will still produce so little power it's probably undetectable except by neutron counter. If you got 1e9 neutrons/sec = .001 watts from WB-6, at r^7 scaling this should give you:Roger wrote:Can scaling be dealt with by Dr Nebel building a WB-8, twice the size of WB-7? In other words can scaling issues be dealt with by building a 1 footer and a 2 footer, that are operating pulsed, as in WB-6 ?
2^7 = 128 x .001 watts = .128 watts
That will not shock the world, though the neutron counts would be very persuasive and could be used to argue the scaling is accurate.
I think the problems are all the unknowns in scaling to rx10. Alpha sputtering, for instance, is likely to be a big issue at rx10, not so much at rx2. Plus, as a man once famously said, there are the known unknowns, and there are the unknown unkowns. It's hard to say what inefficiencies or efficiencies will emerge at larger scales. We'll probably only find them by building it.
I think Bussard was probably right that given our druthers we'd just go for the gold and build the 100MW (which is about rx13). OTOH, we'll get hit with all the scaling issues at once doing that, so it might be a lot harder to get it to work.
Budget realities might decide things. Given unlimited funding, I would think you'd want to simultaneously try rx4, rx8, rx12, rx16. Smaller efforts might present easier problems that could be progessively solved. For that same reason, a limited budget probably means smaller ones first.