Polywell FOIA

jabowery · Post by **jabowery** » Sat Mar 06, 2010 4:58 pm

MSimon wrote:
Due diligence is to be expected and the diligence due on something like fusion is going to be great.
Just look at what we have seen here so far (two or three data points)

1 in 2. 1 in 1,000. 1 in 10^10.

Those numbers are not even in the same ball park.

That's where the value of private capital in risk management comes in. The due diligence phase can be substantial even involving things like _paying_ Bussard and Rider for versions of their theories sufficiently consilient to allow rational (applicable) predictions.

JohnSmith · Post by **JohnSmith** » Sat Mar 06, 2010 5:16 pm

Hey guys, I hate to interrupt, but could you move to general? I'd like to see FIOA info on this thread.

Robthebob · Post by **Robthebob** » Sat Mar 06, 2010 5:24 pm

So the current situation is this.

ICF-too expansive.

Tok- too expansive and plasma instabilities.

stellerator- too hard to design and too expansive.

IEC- grid messes it up.

FRC- same as stellerator.

polywell- physics dont work.

It's always something or another, eh?

chrismb · Post by **chrismb** » Sat Mar 06, 2010 6:00 pm

Robthebob wrote:ICF-too expansive.
Tok- too expansive and plasma instabilities.
stellerator- too hard to design and too expansive.
IEC- grid messes it up.
FRC- same as stellerator.
polywell- physics dont work.

Nothing can be "too expensive" if you really need it.

ICF - Still way off Rayleigh instability criterion (new results suggest improvement?). How to feed fuel pellets? How to maintain laser optics from clouding?

Tok - plasma instabilities, as said, and can only run a 'pulse' until the core saturates

Stellarator - best looking option in my opinion, may over come both tok limitations, but you're dead right - the right design is totally critical.

IEC - grid effect is minimal. All generally cold locally hot devices need to overcome coulomb scattering losses, cross-section scattering>>cross-section fusion. Getting ions 'hot' by e-fields is easy and known. The question is; how do you keep fast ions fast?

FRC - plasma regimes yet to be properly experimented/reported. Theoretically unstable, experimentally seems to be better than theory. How much better? Hardly shirt-off-back-betting material.

Polywell - physics don't work (see IEC).

MSimon · Post by **MSimon** » Sat Mar 06, 2010 6:26 pm

JohnSmith wrote:Hey guys, I hate to interrupt, but could you move to general? I'd like to see FIOA info on this thread.

May I suggest subscribing to my blog:

IEC Fusion Technology

You would get on average 1 alert a month (some months maybe 5 or 6) and I will definitely be doing something on FOIA if anything comes back.

TallDave · Post by **TallDave** » Sat Mar 06, 2010 8:56 pm

Polywell - physics work in theory, real-world scaling TBD

Fixed that for you.

grid effect is minimal.

It's generally accepted as the main problem, your obstinate insistence to the contrary notwithstanding.

The question is; how do you keep fast ions fast?

Easy, you just get rid of the grid. I find it hard believe downscattering is a bigger problem than a large chunk of zero-kinetic-energy metal sitting in the middle of your acceleration space.

If we get WB-8 neutron counts out of this FOIA, it should be pretty clear whether we've been getting beam-background or beam-beam.

KitemanSA · Post by **KitemanSA** » Sat Mar 06, 2010 9:59 pm

WD8 won't be installed for several months. How do you expect to get neutron counts out of this FOIA request?

chrismb · Post by **chrismb** » Sat Mar 06, 2010 10:14 pm

TallDave wrote: It's generally accepted as the main problem....

..by those who have applied little of their own thinking to the issue.

chrismb · Post by **chrismb** » Sat Mar 06, 2010 10:18 pm

TallDave wrote:
The question is; how do you keep fast ions fast?
Easy, you just get rid of the grid. I find it hard believe downscattering is a bigger problem than a large chunk of zero-kinetic-energy metal sitting in the middle of your acceleration space.

Do some sums and show me what you get... If the cross-section for scattering is 10^10 times bigger than the cross section for fusion (that is, you get a fusion once in every 10 trillion collisions) what d'you think happens for the remaining (10^10)-1 collisions? D'you really think the ions keep their energy after so many 'wasted' collisions, or do you think they thermalise with their "collidees"?

TallDave wrote:If we get WB-8 neutron counts out of this FOIA, it should be pretty clear whether we've been getting beam-background or beam-beam.

It can still be quite muddy. What metrics do you say would show this up clearly?

Robthebob · Post by **Robthebob** » Sun Mar 07, 2010 12:28 am

I was kidding with my post.

I'm not quite sure what you mean by core saturates, but basically, Toks dont work. Plasma current, oh geez. Stellarator... well, apparently, it's so hard to design that people would rather try to do toks, which is just impossible to overcome, then to...

Oh well...

MSimon · Post by **MSimon** » Sun Mar 07, 2010 3:07 am

chrismb wrote:
TallDave wrote:
The question is; how do you keep fast ions fast?
Easy, you just get rid of the grid. I find it hard believe downscattering is a bigger problem than a large chunk of zero-kinetic-energy metal sitting in the middle of your acceleration space.
Do some sums and show me what you get... If the cross-section for scattering is 10^10 times bigger than the cross section for fusion (that is, you get a fusion once in every 10 trillion collisions) what d'you think happens for the remaining (10^10)-1 collisions? D'you really think the ions keep their energy after so many 'wasted' collisions, or do you think they thermalise with their "collidees"?

TallDave wrote:If we get WB-8 neutron counts out of this FOIA, it should be pretty clear whether we've been getting beam-background or beam-beam.
It can still be quite muddy. What metrics do you say would show this up clearly?

I believe the the number Dr. B. cited was 60 collisions per fusion.

And what is this 10^10 obsession? Why not 1E8 or 1E17?

TallDave · Post by **TallDave** » Sun Mar 07, 2010 7:11 am

D'you really think the ions keep their energy after so many 'wasted' collisions,

Yes. Where else would the energy go? The ions at the center are at high energies only because of the well. For the same reason, ions at the edge have low velocity and the collision cross-section is greater, so they'll tend to thermalize there at the top of well at low energies, meaning there won't be much upscatter to carry energy away.

or do you think they thermalise with their "collidees"?

I'm sure there's some spread of velocities, but Chacon's paper suggests partially relaxed distributions could yield large Q values.

..by those who have applied little of their own thinking to the issue.

Oh please. People have spent decades thinking about it. As best I can tell, you are the only one who thinks the grid is a minor issue.

TallDave · Post by **TallDave** » Sun Mar 07, 2010 7:36 am

WD8 won't be installed for several months. How do you expect to get neutron counts out of this FOIA request?

I don't expect them (in fact I don't expect to get anything very interesting from the FOIA request), but they're possible. We don't know how long it actually took them to build WB-8; it's not impossible they could be a couple months ahead of the scheduled April 30 completion date and be testing already.

chrismb · Post by **chrismb** » Sun Mar 07, 2010 9:15 am

MSimon wrote: And what is this 10^10 obsession? Why not 1E8 or 1E17?

Typical total collision cross-section for fusible H or D = ~10^-16 cm^2

Typical fusion cross-section for fusible H or D = ~10mbarns

ratio = ~10^10

Sure, that can be modified (a little bit) but is around that value, particularly for the 'lower energy' 10s of keV experiments.

chrismb · Post by **chrismb** » Sun Mar 07, 2010 9:24 am

TallDave wrote:
..by those who have applied little of their own thinking to the issue.
Oh please. People have spent decades thinking about it. As best I can tell, you are the only one who thinks the grid is a minor issue.

Sure, OK maybe they have spent their time thinking about it. I spent my time calculating.

People long to see such a simple device as a fusor working. As the grid is the only thing people can physically see in a fusor, so they blame that for it "not working".

The pretty glow so delights the onlookers that they do not believe it not working is anything to do with that.

WAKE UP!!! That pretty glow is where the energy is getting dumped. If you can plainly see the plasma in a device then it WON'T WORK!

You are right that people have thought the issue is the grid. This is human nature - to imagine whatever is the nature of a thing and then hold on to that belief tenaciously whilst rejecting objective counter arguments. This is how religions get formed, and the majority of people on earth have religious faith. That hardly gives 'religion' the mandate to believe there is a God!!

I'm not into your faith-based approach to fusion science. Please move on... or come up with some objective bits of information.