University of Sydney Makes Small Polywell

MSimon · Post by **MSimon** » Sun Jan 03, 2010 1:05 pm

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http://prometheusfusionperfection.com/2 ... the-scene/

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Tom Ligon · Post by **Tom Ligon** » Sun Jan 03, 2010 2:55 pm

That's about half the size of the dimunitive WB-2, but the coil forms do space the coils.

I did not notice the insulator material, but I get the impression it is a plastic. You could not drive it very hard, but it does appear to be a nice first step. I've been hoping to see amateur fusion efforts on this scale.

John Gallagher · Post by **John Gallagher** » Sun Jan 03, 2010 4:15 pm

The coil forms could be made of Macor. This material is avaliable from McMaster-Carr etc. I have made vacuum heater components out of this material and up to about 700 C it has no problems with outgassing.

TallDave · Post by **TallDave** » Sun Jan 03, 2010 5:39 pm

This was also mentioned at the IEC conference and here:

http://pajamasmedia.com/instapundit/90204/

They apparently drove it to 1T and 250V drive depth.

Tom Ligon · Post by **Tom Ligon** » Sun Jan 03, 2010 9:10 pm

I used a little Macor while at EMC2 myself. Good stuff.

We also used a lower grade green unfired clay from MMC. It was machineable in the green form, then you fired it. Manassas has a ceramics shop that teaches clay arts, and has several local artisans making their wares. For five bucks they would include our parts in their next firing.

They have classes in porcelean, and I always wanted to try my hand at making specialized e-gun parts there.

My observation was that any of these materials, placed at cusps of a Polywell, would produce fireworks when you attempted to drive a deep well. We thought, rather than insulating, they were "charging up" with electrons and then encouraging ions to strike. You can't cheat with insulators.

So, while that insulated magrid is probably good for some low-energy and beam trajectory studies, it is not suitable for actually driving an high-energy well. For that you need a metal surface, and you need to not have an insulator or conductor at any cusp, including the "funny cusp".

But it is a start, and I'm glad to see them working on it.

TallDave · Post by **TallDave** » Mon Jan 04, 2010 3:20 am

My observation was that any of these materials, placed at cusps of a Polywell, would produce fireworks when you attempted to drive a deep well. We thought, rather than insulating, they were "charging up" with electrons and then encouraging ions to strike. You can't cheat with insulators.

Thanks for sharing that, I was wondering how that would work.

TallDave · Post by **TallDave** » Mon Jan 04, 2010 3:26 am

Here's the ppt:

http://fti.neep.wisc.edu/static/TALKS/1 ... tthewc.ppt

If you can't open ppt:

Size limitations and inductance argument dictate we should use a small number of turns and provide a large base load current.
To achieve 1 Tesla of magnetic field in polywell faces of 6cm diameter, we require a current of 10kA.
10 turns is a middle ground between size and inductance limitations, and the need for a more practical base current of 1kA.
10 turns reduces asymmetry effects from feed lines

Critically damped current pulse from a capacitor in near short circuit conditions.
Our capacitors are 1.5mF Aluminuim electrolytic
Voltage rating of 450Vdc
By using only ten turns per coil, we have kept our resistance and inductance low, close to critical damping conditions.

Forming potential wells with the polywell is definitely possible
Achieved floating potentials as deep as 250V
Time scales vary over 3-5ms
Explore; pressure, field strength, electron injection energy, electron injection current, and injection angle.

Tom Ligon · Post by **Tom Ligon** » Mon Jan 04, 2010 3:32 am

I really need to get a .ppt reader for this old computer. Right now only my laptop has PowerPoint, and it is momentarily unavailable.

I really like AskMar's policy of posting .pdf files instead of .ppt.

MSimon · Post by **MSimon** » Mon Jan 04, 2010 4:06 am

Tom Ligon wrote:I really need to get a .ppt reader for this old computer. Right now only my laptop has PowerPoint, and it is momentarily unavailable.

I really like AskMar's policy of posting .pdf files instead of .ppt.

Have you tried Open Office? It is free. Supported by Sun.

http://www.openoffice.org/

kunkmiester · Post by **kunkmiester** » Mon Jan 04, 2010 6:39 am

Second open office. You'll have to redo your file associations--ms doesn't like third party software for their stuff, but it'll do just fine. It just takes it a minute or two to convert the file so it can open it.

Skipjack · Post by **Skipjack** » Mon Jan 04, 2010 12:10 pm

OpenOffie is pretty good. I use it too. Only have one MS Office version at work for compatibility reasons. Everything else is done with Open Office.

BenTC · Post by **BenTC** » Mon Jan 04, 2010 1:30 pm

Tom Ligon wrote:I really need to get a .ppt reader for this old computer. Right now only my laptop has PowerPoint, and it is momentarily unavailable.

How old, what operating system? For Windows 2000 or later try Microsoft PowerPoint Viewer 2007
Otherwise, if you trust they won't scrape your email for spam, try http://www.freepdfconvert.com/
Or OpenOffice.

For anyone wanting to create PDFs for free, my recommendation the last three years is http://www.cutepdf.com/

Robthebob · Post by **Robthebob** » Mon Jan 04, 2010 7:00 pm

It seems like just making the polywell (the virtual anode) without using to fuse anything seems to be not too hard, at least not impossible for someone like me. I may make one when I'm in grad school.

Anyone know, without fusing anything, if you continue the operation, would the virtual anode be okay? There's nothing there to thermalize or anything.

Tom Ligon · Post by **Tom Ligon** » Mon Jan 04, 2010 9:14 pm

The description of the device above suggests pulsed magnets, very high current for microseconds. They evidently don't aim for a sustained well.

WB2 would run for seconds to a minute depending on the magnet current. I believe the peak field strength was maybe a couple of kilogauss on-axis. Pulsed it could have hit higher.

Nobody, to my knowledge, has ever built a WB2-sized unit with the WB6 form factor (spaced coils with circular cross-section). This is a challenging construction project, but I would think it would be in the range of possibility for a graduate research project or even a determined amateur. It is probably too small to have any hope of DD fusion. WB2 was unable to stand 5 kV (we fried it a little over 4 kV), but could handle 1 kV and a well-built model might handle more.

FAMULUS · Post by **FAMULUS** » Mon Jan 04, 2010 10:02 pm

I did a question and answer with project leader Joe Khachan:

http://prometheusfusionperfection.com/2 ... e-khachan/