Talk-Polywell.org

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http://breakthroughalert.com/2008/12/ca ... tical.html

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Those are steam driven pistons. The empty holes are for more pistons.

http://en.wikipedia.org/wiki/Magnetized_target_fusion

MTF's challenges appear to be similar to those of ICF. In order to produce power effectively the density has to be increased to a working level and then held there long enough for the majority of the fuel mass to undergo fusion. This is occurring while the foil liner is being driven inwards. Any mixing of the metal with the fusion fuel will "quench" the reaction (similar problems occur in MCF systems when plasma touches the vessel wall). Similarly, the collapse must be fairly symmertical to avoid "hot spots" that could destabilize the plasma while it burns.

Problems in commercial development are the similar to those for any of the existing fusion reactor designs. The need to provide high-strength magnetic fields at the focus of the machine is at odds with the need to extract the heat from the interior, making the physical arrangement of the reactor a challenge. Additionally, the fusion process gives off large numbers of neutrons (in common reactions at least) that lead to neutron embrittlement that degrades the strength of the support structures and conductivity of metal wiring. These neutrons are normally intended to be captured in a lithium shell in order to generate more tritium to feed in as fuel, further complicating the overall arrangement.

It is a kluge. A crufty kludge. A crock.

http://www.dourish.com/goodies/jargon.html

the breakthrough alert was to my article

general fusion update

The company has done some physical proof of concept tests with modest amounts of fusions. It was at 1/25th speed. 4 meters/second instead of 100 meters/second

They have their own venture capital funding. I am interested to see if they can scale up and prove out their $10 million energy breakeven design.

http://www.generalfusion.com/files/evidence.pdf

http://www.generalfusion.com/files/acoustic_wave.pdf

http://www.generalfusion.com/files/external_review.pdf

From the external review: Ronald C. Kirkpatrick, retired Visiting Scientist Los Alamos National Laboratory

7. The plasma formation approach seems adequate for the current experiments, but in the future it may be prudent to examine other methods, perhaps including an en-situ approach using a discharge through a frozen deuterium fiber.
8. Dr Laberge's reactor concept based on his MTF approach seems reasonable, but will eventually need a more thorough analysis. He has made valid estimates, and the general concept is interesting, possibly even viable. However, the most important objective for now should be to thoroughly understand the current experiments and how their performance can be enhanced in the future. The data from these experiments and the quantitative understanding gained should allow a more secure projection of the potential for this MTF approach as a basis for a fusion reactor

Brian Wang

I like them. Nothing I've read seems particularly unworkable, they have done experiments and are attempting to be peer reviewed.

That said, if they were anywhere but Canada, I'd suggest they try and get a few grants for some kind of modern art.

How are they going to manage diagnostic ports? It seems their sonic convergence has to be perfect. You can't put so much as a needle in there.

The thing is a magic black box. Either Fusion heat can be extracted from it or it can't; If it can't you won't know anything about it, and it looks like any follow on hypothesis will be very much blind guesses.

I don't see this as a very interesting experiment. To me interesting experiments can have follow on hypothesis and associated experiments in rapid succession. They got no diagnostics, and they got no interesting knobs either.

I like polywell, small tokamaks, and I'll like the NIF.

It may eventually generate net gain with 200 steam driven pistons, but somehow I don't see it as a spacecraft engine enroute to Saturn's moons.

Two hundred or more steam driven pistons synchronized to better than 100 nanoseconds for a confinement time of 1 uSec? Or maybe 10 nSec synchronization to give you some margin. Light travels 3 meters in 10 nS. So you have to compensate for that.

Nothing fundamentally impossible there. Physically impossible maybe. But fundamentally? No. As long as you can get the timing that tight. The wear co-efficients very small and equal. The steam temperature at each cylinder inlet to within 1 deg F or less. Proper end caps on your rotating fluid metal cylinder. Valves that can open reliably within 1 to 10 nS of each other.

Etc. Etc. Etc.

This is not a fusion reactor. It is a mechanical engineers wet dream or nightmare depending.

I don't think I agree with you, Helius.
I'm only guessing, but I think that as long as the pistons are arranged symmetrically, you could replace a few with instrument ports. And if you're talking about measuring at the core, well, Polywells suffer the same problems.

Sherlock Holmes and the Case of the Missing Fusion Device!

Rube Goldberg would be proud.

This seems a lot like the photo luminescence guys who were putting powerful speakers all around a large plastic or glass sphere. The speakers all pointed radially inward, so the sound waves focused at the center. They filled the thing with water, or other liquid, put fuel at the center and blasted it with sound. I don't know if they ever got any neutrons. I do know that they were looking for money to test a large system. They were hoping to drive the system at resonance, I believe.

General Fusion's concept is described as the steampunk approach to fusion power.

JohnSmith wrote:I don't think I agree with you, Helius.
I'm only guessing, but I think that as long as the pistons are arranged symmetrically, you could replace a few with instrument ports. And if you're talking about measuring at the core, well, Polywells suffer the same problems.

No you can't. Perfect mechanical symmetry is broken. And then the question is how do you do diagnostics inside a liquid metal rotating cylinder?

With Polywells you can do radio wave tomagraphy.

300 MHz = 1 m wavelength
3 GHz = 10 cm wavelength
30 GHz = 1 cm wavelength
300 GHz = 1 mm wavelength

Resolution should be about 1/10th of a wavelength. 100 GHz is everyday stuff. Off the shelf parts. Pricey but you can go to the store and get them.

So that is 3 mm wavelength and .3 mm (10 thousandths of an inch) resolution.

Now you need a continuous operation machine (probably) to do all that in a reasonable length of time. But you can do it.

A nice magazine:

http://www.mwrf.com/

Read the ads.

DC to 110 GHz: http://www.hittite.com/

This is basically LINUS revisited. LINUS was an experiment done at NRL in the 70s where a plasma was imploded with a liquid wall. I believe the plasma was a Z-Pinch. The idea behind MTF plasmas is that the magnetic fields provide thermal insulation, but not confinement forces which come from the liner, or in this case an imploding wall. I believe that they are using FRCs as the target plasma. I don't know where they are with the program, but in my opinion this is an approach which should be taken seriously.

I think I saw someone else asking this before:
why so many pistons? One should assume that you can shape the shockwaves in a different fashion, especially in a liquid?
Maybe I am missing something...

You only need diagnostics if it _doesn't_ work. If it works, then you
get neutrons. Given the amount of gas and number of neutrons detected
you can figure out the compression ratio of the shock.

These guys aren't looking at this as a physics experiment, they are
looking at it like a business experiment. They got nice press in Popular
Science (although the author didn't know the difference between a
neutral beam and a beam of neutrons and I bet the audience won't
either).

It's a great way to make a living and I admire them for trying. They can
always go back to making printers when the money dies out.

rnebel wrote:This is basically LINUS revisited. LINUS was an experiment done at NRL in the 70s where a plasma was imploded with a liquid wall. I believe the plasma was a Z-Pinch. The idea behind MTF plasmas is that the magnetic fields provide thermal insulation, but not confinement forces which come from the liner, or in this case an imploding wall. I believe that they are using FRCs as the target plasma. I don't know where they are with the program, but in my opinion this is an approach which should be taken seriously.

Welcome back Dr. Nebel, and congratulations on your review.