Lawaranceville E-Newsletter

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

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Aeronaut
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Postby Aeronaut » Tue Apr 13, 2010 9:41 pm

Thanx for the link, MSimon. I read and studied the pix on the entire thread, and now have some type of an understanding how the PW should work.

Torulf, your work always blows me away! Great images, as always. Just didn't realize they were spread between flickr and photobucket.

Kiteman, the target that I'm leading has the least financial risk and shortest published U-Day deadline. It's also the easiest to mass produce and market, which is required in order to reduce carbon emissions in any meaningful time frame. But now I have several reserve targets...

Aero, you're spot-on about making educated guesses in cartoon engineering. Once I sketch something- or attempt to- I tend to see questions and misunderstandings that don't show up in my head.

Everybody, I can sketch exploded and cutaway drawings almost photo-realistically in pencil, but I'm math and physics challenged. So the argument of superior theory means nothing to me. I highly recommend that you make the gallery thread(s) stickies, above the fold. This could be labeled something like Start Here For Best Experience.

Just my 2 bits :)
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Skipjack
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Postby Skipjack » Wed Apr 14, 2010 9:58 am

Another article on Focus Fusion:

http://newenergyandfuel.com/http:/newen ... us-fusion/

Well, we will see what happens. Sure interesting times that we are living in right now.

Aeronaut
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Postby Aeronaut » Wed Apr 14, 2010 1:19 pm

Thanx for the link, Skipjack. He did an excellent job of explaining the program without getting bogged down in theory.
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choff
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Postby choff » Thu Apr 15, 2010 1:01 am

I'd be curious if they could improve performance by placing another dipole in the chamber opposite the main one, but fire it with reverse polarity at the same time.
They would have to be spaced apart to prevent arching but allow for a single larger plasmoid.
CHoff

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Postby choff » Thu Apr 15, 2010 1:01 am

I'd be curious if they could improve performance by placing another dipole in the chamber opposite the main one, but fire it with reverse polarity at the same time.
They would have to be spaced apart to prevent arching but allow for a single larger plasmoid.
CHoff

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Postby Aeronaut » Thu Apr 15, 2010 6:05 pm

choff wrote:I'd be curious if they could improve performance by placing another dipole in the chamber opposite the main one, but fire it with reverse polarity at the same time.
They would have to be spaced apart to prevent arching but allow for a single larger plasmoid.


Wouldn't work, Choff, because that's where the inductive converter- what we call the drift tube- goes. Assuming a working machine, the easiest way to increase power output is to increase the trigger pulse rate. Since that'll be under software control, response to load fluctuations can limit a voltage sag to one side of the output sine wave, if that.

The upper limit is imposed by anode cooling limitations- it's too small to think realistically about going after the 50MW class with a single machine. But it is cheap enough to use 3 or 4 machines.

Preliminary testing suggests that the angular momentum coil may control plasmoid diameter as Aaron Blake's theory suggests in the patent. Other ways to influence performance are to vary electrode dimension(s) and/or geometries, fill gas combinations (theory suggests higher compression of heavier gasses) and cap charging voltages.

You can see this all lining up in the planned move to shorter electrodes, which increases peak current, thus peak field strength. Heavier gasses will test the compression theory for a cross check, then it's only a matter of demonstrating pB-11 fusion and then tweaking for ever-better performance.

Assuming LPP does at least reach unity this year or within a few years, be looking for all sorts of "secret sauces" tweaking one or more of those variables for a specific marketing edge :idea:
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choff
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Postby choff » Fri Apr 16, 2010 12:02 am

So two dipoles couldn't share the same drift tube and the plasmoid is stationary in space. If the tube was off to one side I was hoping either two dipoles could make a larger plasmoid or collide two plasmoids. Hopefully anode cooling won't be a killer show stopper for them.
CHoff

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Postby Aeronaut » Fri Apr 16, 2010 2:29 am

choff wrote:So two dipoles couldn't share the same drift tube and the plasmoid is stationary in space. If the tube was off to one side I was hoping either two dipoles could make a larger plasmoid or collide two plasmoids. Hopefully anode cooling won't be a killer show stopper for them.


The FF's ion beam is very tightly focused, which would also rule out 2 dipoles. But both converter subsystems will be tiled from smaller modules optimized for specific energy levels.

A key point that's easy to forget is that the entire machine cycle is around 1 uS, with a plasmoid life of maybe 20nS. It helps to think of a flowing process rather than PW's steady state design.

Cooling limits are expected somewhere between the 5MW to 20MW range, and again, I expect market pressures to keep extending it, something like HDD capacity.
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Skipjack
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Postby Skipjack » Fri Apr 16, 2010 11:04 am

Cooling limits are expected somewhere between the 5MW to 20MW range, and again, I expect market pressures to keep extending it, something like HDD capacity.


Yes, once (if) we get to see a working fusion reactor concept, things will get improved upon really quickly. From what I understand DPFs are rather cheap to build so there would be a lot of people doing it. That would mean a lot of improvements very quickly. The more expensive the system, the less competition and the slower improvements. That is another reason why ITER is such a bad idea. The whole thing is just waaay to expensive.

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Postby Aeronaut » Fri Apr 16, 2010 11:47 pm

Skipjack wrote:
Cooling limits are expected somewhere between the 5MW to 20MW range, and again, I expect market pressures to keep extending it, something like HDD capacity.


Yes, once (if) we get to see a working fusion reactor concept, things will get improved upon really quickly. From what I understand DPFs are rather cheap to build so there would be a lot of people doing it. That would mean a lot of improvements very quickly. The more expensive the system, the less competition and the slower improvements. That is another reason why ITER is such a bad idea. The whole thing is just waaay to expensive.


Theoretically, any self respecting fab shop could build one if they had the blueprints or at least the math and theory skills to determine their own custom dimensions and spacings.

The budget busters begin with the cap bank, switches, vacuum system, and so on. So the core is a tiny part of the system expense and challenge.

PB-11 fueled architectures automatically ditch the capital expense of the steam cycle, resulting in unheard of ROI time frame potentials.

And like you said, all it takes is for one to reach unity to get the fuel legitimized for organized science to jump on the bandwagon.
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Postby Brian H » Wed Apr 21, 2010 12:35 am

D Tibbets wrote:...

...
The onl;y pratical way to collect the x-ray energy is to let it head the container and them produce electrical power through a conventional steam plant. If the Q (excess fusion energy out) is not high (eg: greater than 10, you will need to recover as much of the input energy (like bremsstrulung X-rays) and fusion energy that you can.
...

Dan Tibbets

Dan Tibbets

Not so. The X-ray harvesting is also non-thermal; the patent describes a photoelectric method: layered foils each knocking down the energy levels of the X-rays and draining electrons/current, sufficiently thick and efficient to absorb all X-radiation in the "shell" of the device.
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Postby D Tibbets » Wed Apr 21, 2010 6:16 pm

Brian H wrote:
D Tibbets wrote:...

...
The onl;y pratical way to collect the x-ray energy is to let it head the container and them produce electrical power through a conventional steam plant. If the Q (excess fusion energy out) is not high (eg: greater than 10, you will need to recover as much of the input energy (like bremsstrulung X-rays) and fusion energy that you can.
...

Dan Tibbets

Dan Tibbets

Not so. The X-ray harvesting is also non-thermal; the patent describes a photoelectric method: layered foils each knocking down the energy levels of the X-rays and draining electrons/current, sufficiently thick and efficient to absorb all X-radiation in the "shell" of the device.


True, I watched the Google video again. His scheme may be robust enough to be usefull. I was thinking of a photovoltaic effect proposed by someone on Physicsorg. com several years ago. The admitted problem was the extreamly short lifetime of the system (the x-rays quickly fried the delicate circuits). Learner's layered betavoltaic like approach approach may be robust enough to be pratical.

Given efficient x-ray energy recovery and some solution to rapid cathode erosion, the claimed Q of ~ 1.8 would be the greatest economic limitation. Given 80% conversion of fusion charged particle energies and bremsstrulung x-ray energy recovery means that for every 1 MW of energy input (= waste heat) there would be ~ 1.5 MW of usefull electrical output. The machines are small, but with the ~ 500 KW of excess power out you would have to cluster alot of machines to generate ~ 100's MW powerplant outputs. Also, since the machines are small, the heat loads per square meter of structure would be large. If the waste heat could be used for process heat, that would help some. A few dozen units might power an ethanol plant efficiently (need both electricity to power various processes, and heat to cook and distill the feed stock). Having a Q of 10-20 would greatly benifit scaling to large power outputs.

As has been mentioned, a DPF, even at much lower efficiencies would make an excellent neutron source for a fusion/ fision hybird plant (using D-D as the fuel). It may have cheaper life cycle costs compared to a larger FRC system, and it's small size (without the X-ray shield) might be ideal for embeding within a fission structure.
The need to extract the fusion reactor core every few weeks (due to erosion of the berillium anode and the cathodes) in the neutron rich enviornment might be a problem. A FRC fusion core would have similar neutron concerns, but may need replacement much less frequently.
Similar arguments might be made about the Polywell, but the claimed benifits in Q means that the hybird approach would be less competative (if the systems work at all). All three would have large benifits over a Tokamac approach because tritium is not needed (though it would still be a concern as it would be a waste product, just not as much effort would be needed to actually produce it as it is a primary fuel as in Tokamacs).
Also, the explosive quenching risk in the huge Tokamac superconducting magnets (with secondary shattering of the highly radioactive fission portion of the reactor) would be a greater safety hazard.

Dan Tibbets
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Postby Brian H » Wed Apr 21, 2010 7:30 pm

D Tibbets wrote:...
Given efficient x-ray energy recovery and some solution to rapid cathode erosion, the claimed Q of ~ 1.8 would be the greatest economic limitation. Given 80% conversion of fusion charged particle energies and bremsstrulung x-ray energy recovery means that for every 1 MW of energy input (= waste heat) there would be ~ 1.5 MW of usefull electrical output. The machines are small, but with the ~ 500 KW of excess power out you would have to cluster alot of machines to generate ~ 100's MW powerplant outputs. Also, since the machines are small, the heat loads per square meter of structure would be large. If the waste heat could be used for process heat, that would help some. A few dozen units might power an ethanol plant efficiently (need both electricity to power various processes, and heat to cook and distill the feed stock). Having a Q of 10-20 would greatly benifit scaling to large power outputs.

As has been mentioned, a DPF, even at much lower efficiencies would make an excellent neutron source for a fusion/ fision hybird plant (using D-D as the fuel). It may have cheaper life cycle costs compared to a larger FRC system, and it's small size (without the X-ray shield) might be ideal for embeding within a fission structure.
The need to extract the fusion reactor core every few weeks (due to erosion of the berillium anode and the cathodes) in the neutron rich enviornment might be a problem.
...
Dan Tibbets


The cooling of the electrodes is expected to constrain the power levels, which scale with the "shot" frequency; about 330Hz would probably be the sweet spot to begin with, which would generate about 5MW. The neutrons are few, only resulting from side reactions, and are slow, not fast. They will be stopped by a water/B10 shell enclosing the entire rig. No radiation above ambient is expected outside the shell.

As for electrode erosion, that would be correspondingly less, since there is no fast neutron flux. Servicing is expected semi-annually or less.
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Postby Skipjack » Wed Apr 21, 2010 7:36 pm

Well, I see that if they are that small, they could probably have applications in areas where larger systems can not be used?
Like heating and electricity for small communities.
This thing seems to be cheap enough for that.

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Lawrenceville Update

Postby Brian H » Wed Apr 21, 2010 7:43 pm

D Tibbets wrote:...
Given efficient x-ray energy recovery and some solution to rapid cathode erosion, the claimed Q of ~ 1.8 would be the greatest economic limitation. Given 80% conversion of fusion charged particle energies and bremsstrulung x-ray energy recovery means that for every 1 MW of energy input (= waste heat) there would be ~ 1.5 MW of usefull electrical output. The machines are small, but with the ~ 500 KW of excess power out you would have to cluster alot of machines to generate ~ 100's MW powerplant outputs. Also, since the machines are small, the heat loads per square meter of structure would be large. If the waste heat could be used for process heat, that would help some. A few dozen units might power an ethanol plant efficiently (need both electricity to power various processes, and heat to cook and distill the feed stock). Having a Q of 10-20 would greatly benifit scaling to large power outputs.

As has been mentioned, a DPF, even at much lower efficiencies would make an excellent neutron source for a fusion/ fision hybird plant (using D-D as the fuel). It may have cheaper life cycle costs compared to a larger FRC system, and it's small size (without the X-ray shield) might be ideal for embeding within a fission structure.
The need to extract the fusion reactor core every few weeks (due to erosion of the berillium anode and the cathodes) in the neutron rich enviornment might be a problem.
...
Dan Tibbets

There was/is another development branch of the device which had been planned as a preliminary/parallel financing source called 'X-Scan'. It was/is a way to generate intense X-rays for use in structural crack detection, etc. This is the link on the Lawrenceville PP site:
http://lawrencevilleplasmaphysics.com/i ... &Itemid=83
This source will be integrated into an inspection device that will be able to scan roads, bridges and buildings with source and detector both located within the truck (or on a gantry). The X-ray source will repeatedly pulse as the truck moves, emitting sheets of X-rays collimated by lead shields.

I'm not sure what the status of that project is at the moment; I suspect that it's in abeyance until the basic rig is proven.
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