"Time to Fusion", "Ion-Ion Collision Time&quo

Discuss how polywell fusion works; share theoretical questions and answers.

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ladajo
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Post by ladajo »

In following this last bit of back and forth, I got to thinking about the collision angle aspect in fusion events. Then that made me think about the well depth and associated ion energies. Granted it seems logical that the highest density collision area (and thus energy production) area is going to be 'the core' sphere, but there will be offcentered collisions as well. And in that some of those will retain sufficient ompf to fuse, and in that affect the ion lifetime. How is that accounted for properly in the math guesstimates?

Ivy Matt
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Joined: Sat May 01, 2010 6:43 am

Post by Ivy Matt »

icarus wrote:Plural of "formula" is "formulae".

Latin.
Four of six words are Latin-based. Not bad. Most of us have lower Latin-to-English rationes, however.

chrismb
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Joined: Sat Dec 13, 2008 6:00 pm

Post by chrismb »

Ivy Matt wrote:
icarus wrote:Plural of "formula" is "formulae".
Four of six words are Latin-based. Not bad. Most of us have lower Latin-to-English rationes, however.
Languages are what they are, and english is a live one. It is undergoing constant change, and the '-s'ification of latin words is becoming established and legitimised 'through habitual use'. Words mean what we say they mean, no more nor less. They are tools we use, we are not their servants.

My opinion is that the whole of english spelling, for example, should be re-written into a phonetically consistent dictionary. All this spelling silliness is just that, silly.

Ivy Matt
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Joined: Sat May 01, 2010 6:43 am

Post by Ivy Matt »

So you're of the opinionis that Noah Webster didn't go far enough? :wink:

chrismb
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Joined: Sat Dec 13, 2008 6:00 pm

Post by chrismb »

I'd never hear of him.. at least, I did not know that was the 'Webster'.

Ah! So wiki tells me it is Webster that got America spelling 'color' and 'center'. Well, I suppose it is a start. Still inconsistent, in the first the two vowel sounds are the same, yet one is 'o' and the other is 'or'. Whereas 'center' uses 'e' in two vowel sounds that sound different.

I would be a bit more radical, more like 'culu' and 'sentu' [No, not a long 'u' (not 'sentoo'), I'd spell long u's like 'oo'. e.g. 'You' would have to become 'Eoo']

...it's easy to rattle on pointlessly about something that is never going to happen, eh!?...


[edit .... sorry, just realised this was the theory thread. Best we cap this chat.]

chrismb
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Joined: Sat Dec 13, 2008 6:00 pm

Post by chrismb »

ladajo wrote: How is that accounted for properly in the math guesstimates?
'guesstimates'..Exactly. The maths is, indeed, only a 'representation' of what may go on. The actual scattering and energy losses of those scattered particles is a stochastic process and this is why [IMHO] theoretical number crunching never shows what might really happen.

But it gives the basic outline and so long as two ions have a chance of colliding at some intermediate distance from the centre, they may be scattered obliquely, which'd result in one overshooting the wiffleball edge and the other never getting there, thus these particles will never anneal, even if that process exists. The maths gives a flavour for this, but it would be a foolhardy claim to say it can't work out. My opinion is that it won't - that's just an opinion supported by my experience in system instabilities. Even if I make only casual observations, it is still not an unreasonable conclusion, given the dearth of real plasma data in the last 25 years.

D Tibbets
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Joined: Thu Jun 26, 2008 6:52 am

Post by D Tibbets »

Chrismb. I think your reasoning is flawed. I have questions about what happens to the down scattered ions. But, the upscattered ions , pass through the annealing zone, both on their outward trip and their inward trip (if upscattered to much they are turned by the b-field, or they hit a cusp and they are lost). They do not need to stop and reverse in this arbitrary annealing zone- otherwise, why talk about annealing anyway as the ions would have the same energy. Passing through this low energy, high collisionality zone they would thermalize with these slow ions lingering in this low average energy turn around zone.
My best guess for the down scattered ions being rehabilitated is based on the shape of a graph of a thermalized plasma. As the plasma tries to relax towards a Maxwellian distribution, the average energy is well below the mean energy. This suggests that there are sufficient ions above the average energy level to boost these slow ions. ( I know, it is speculative, and unsupported). Also, if there is little convergence. these near random directions would place these slow ions occasionaly in the annealing zone, and again the high collisionality in this area would quickly thermalize the slow ions (along with the fast) to a thermal spread around this low energy average. Recall, that this is a thermalized plasma in this zone, but the spread, while large compared to the average energy in this zone is small to tiny compared to the maximum kinetic energy the ions achieve in the potential well.
EG: a spread of 100eV +/-100 eV is large, but spread of 50,000 eV +/- 100 eV is small.

Dan Tibbets
To error is human... and I'm very human.

mattman
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Joined: Tue May 27, 2008 11:14 pm

Just posted Part II

Post by mattman »

Gentleman,

I want to state, I am just trying to explain the current, published work, on the Polywell. We will never get the real funding this project needs until:

1. We have data that says it could work.
2. We show theoretically it could work.
3. Or we have both.

You will never get millions from any organization until that happens. Established, legitimate science has to be demonstrated. By explaining Rider's counter argument, I am providing a public service. So that the "public" or internet community, can figure out if Rider made a mistake.

Feel free to disagree with Rider.

Feel free to find mistakes in this work.

All I ask is that you argue on the high plain of ideas - not degenerate into name calling. I have allot of respect for you guys. This stuff is not easy to understand.

http://thepolywellblog.blogspot.com/201 ... rt-ii.html


I will get a response to the comments from November out soon.

Will
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Joined: Mon Nov 10, 2008 3:21 am

Post by Will »

I do wonder how much practical information you could derive from a fully formed, micro-scale polywell.

Say with a volume inside the magnets of 10cm in diameter?

Could this be built and be useful, and how much would it cost to build?

EDIT: This is my kind of coded way of asking if this is a type of thing that someone (me) should look into doing. Dropping a few grand on vacuum pumps and the like doesn't sound like a bad trade for a small-scale fusion reactor on my desk.

KitemanSA
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Location: OlyPen WA

Post by KitemanSA »

chrismb wrote: I would be a bit more radical, more like 'culu' and 'sentu' [No, not a long 'u' (not 'sentoo'), I'd spell long u's like 'oo'. e.g. 'You' would have to become 'Eoo']]
Hooked on ebonics, hunh?

D Tibbets
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Joined: Thu Jun 26, 2008 6:52 am

Post by D Tibbets »

Will, what you contemplate is being done by a University in Australia.
The problem with small scale is that there is not much room for instrumentation. Also, Nebel said that outgassing becomes too much of a problem. I'm not sure about this. Certainly vacuum pumping capacity improves with smaller sizes, and I don't know why outgassing would be more of a problem as it is dependant on exposed surface area. I'm uncertain if creating similar strength magnetic fields would be a problem. If the face cusp strengths are the measure then the magnetic field strength in these regions may scale similarly. If the edge /'funny' cusps magnetic field strengths is the measure, smaller sizes have distinct disadvantages as the spacing would not change. And certainly, with efficiencies and instrumentation used in WB6, the claimed performance could not have been detected as the neutron counts would not have been above background. Perhaps some plasma chariteristics could have been (and was) measured, but that was less impressive, though perhaps just as significant.

Having said that, the eureka changes in WB6 were very important, but I wonder if the work with the small copper block machine was just as significant. It was small (~10cm?), but they poured so much current through it that they generated magnetic fields of ~ 3 Tesla (thirty times stronger than WB6). That this made ~ 1,000,000 neutrons per second equivalent, with a ridiculously low potential well of only ~ 300 volts is impressive. The only explanation is that the polyhedral fields indeed trapped electrons, and thus ions, as claimed. And, also demonstrated the profoundly impressive magnetic scaling in these devices. The loss scaling of course, is another matter (which is what WB6 improved on).
Which brings up another point about which I'm confused. WB 4 had B fields similar to mildly stronger than WB6, yet it made ! ~ 1000 times less fusion. The losses would have been greater, but I'm uncertain why the fusion rate was less. Bussard spoke of struggles developing deep potential wells due to the rapid loss of electrons to structures. Perhaps this was the differences. Was the achieved potential wells obtained similar between WB4 and 6? Did WB 4 achieve similar WB trapping factors (densities)? Was the power supplies of WB 4 insufficient to make up the relatively huge electron losses in WB4?. Was the background vacuum limits worse in WB4? Due to the square magnet crossections, with the corners less well shielded, would arcing occur at lower densities, such that the background pressure had to be mainbtained at eg- 1/30th the background density of WB6? If so, even with similar Wiffleball trapping factors, the achievable density would have been ~ 1/30th, so the fusion rate would have been ~ 1/1000th, as the fusion rate scales as the square of the density. Was it a combination of these factors?

Dan Tibbets

Dan Tibbets
To error is human... and I'm very human.

ladajo
Posts: 6258
Joined: Thu Sep 17, 2009 11:18 pm
Location: North East Coast

Re: Just posted Part II

Post by ladajo »

mattman wrote:Gentleman,

I want to state, I am just trying to explain the current, published work, on the Polywell. We will never get the real funding this project needs until:

1. We have data that says it could work.
2. We show theoretically it could work.
3. Or we have both.

You will never get millions from any organization until that happens. Established, legitimate science has to be demonstrated. By explaining Rider's counter argument, I am providing a public service. So that the "public" or internet community, can figure out if Rider made a mistake.

Feel free to disagree with Rider.

Feel free to find mistakes in this work.

All I ask is that you argue on the high plain of ideas - not degenerate into name calling. I have allot of respect for you guys. This stuff is not easy to understand.

http://thepolywellblog.blogspot.com/201 ... rt-ii.html


I will get a response to the comments from November out soon.
Currently the funding conjecture you propose is in the complete hands of the navy. They (the special few) do have the data, and do know how it is tracking. They will authorize more funding based on results. They are already on tap for $4 mil for WB8.1 if WB8 pans out as expected. If WB8 does not "play a full game", they may still authorize funds for a 100MW D-D DEMO. WB8.1 is only to test for pB&J feasibility based on promising enough results from WB8.
The real issue is not money it is control of the technology if it pans out. EMC2 deserves return on investment, as does the navy. This is really where it gets fun.
If you want to argue over funding to pursue polywell research if the navy determines it is not worth pursuing, that is a different argument.

Your current argument appears to be it is not funded and it needs some. That is not true.

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