Talk-Polywell.org

Does anybody have any ideas how to do small-scale experiments that could be done cheaply?

What I would like to know is whether it would be possible to prove electron recirculation without a vacuum chamber?

A vacuum chamber is essential. The best we can do without it is a simulation. See http://www.mare.ee/indrek/ephi/ They simulated one electron. It appears to be able to give the trajectory of electrons but will not simulate electron-electron collisions, or electron-ion collisions, or the influence of the electric fields, or the development of instabilities.

So there is no way to do any experiments without a vacuum chamber?

From http://en.wikipedia.org/wiki/Mean_free_path , the mean free path of a molecule in air at atmospheric pressure is 68 nm. This is probably comparable to the mean free path of an ion. I think a free electron would attach itself to a molecule the first time it hit one.

Isn't there something about mean free path not always applying in some cases, I seem to remember reading someplace recently.

I also seem to remember something about rather than going for a vacuum, going the oppersit way and increasing pressure may work.

Even if this open air depature could create a negative well, it could produce lots of hazardous ozone.

Here is a rendering I made of what a polywell with 7 inch outer diameter solenoids would look like in a 24 inch diameter sphere, with a cage with edges measuring 13 inches.


By my calculation, the cage edge could be as much as 13.8 inches and still fit in the sphere.
Picture the 12 inch radius going to the corer of the cage, which is touching the inside of the sphere. The pythagorean formula for three identical dimensions should solve for half the cage edge.
12^2 = 3(x/2)^2
x = 13.8564

Obviously insulated leads to the core and emitters are missing from my diagram. The vacuum feedthroughs for anything that connects to the core should be located on one half of the sphere so the sphere can be opened up. The emitters could be on the corners of the cage.

The flanges that would attach the two hemispheres together and provide attachment to vacuum pump are also absent from my rendering.

I have estimated the cost, and (minus labor, rent, and the cost of any machining) I think something about this size could be produced and tested for under $10 grand in U.S. dollars.

I also think that perhaps cores could be produced cheaply by injecting castable insulation inside the vacuum chamber into a mold that sorrounds the magnet wire. After the sphere is opened and the mold is removed, a conductive layer would be painted on. Then the cage and emitters would be put into place, and the vacuum chamber re-established with polywell ready for testing.

It would need an fuel ion source to be able to do fusion.

Nanos wrote:Isn't there something about mean free path not always applying in some cases, I seem to remember reading someplace recently.

I also seem to remember something about rather than going for a vacuum, going the oppersit way and increasing pressure may work.

You can run plasma in an atmosphere, it's usually called lightning. As pointed out by MisterX, recombination is a killer (fortunatly for us!) You can do something similar to the plasma speaker from the 1980's and that is to fill a region with helium and then strike an arc - but that just helps maintain the arc and is still a low density plasma.

Starting with a vacuum really makes doing the physics a lot easier. I grabed a vacuum pump from the trash bin a few years back, and rebuilt it. With luck, I can use it with some stainless pots and pans to build a really cheap experiment. But learning to weld will also be an important part of the process.

I think it's possible to build really cheap experiments, but for this kind of thing, "cheap" is in the 100's to 1000's of dollars (US).

Perhaps it would be quicker and less expensive to hire Indrek Mandre or someone else to follow up on his simulations. See http://www.mare.ee/indrek/ephi . Because electrons cost 10kev apiece, the electron confinement time is critical. The one electron he simulated did not go very far. However, I don't know how realistically his parameter are compared to a real machine.

A cheap TIG welder that it appears one needs to weld the pots and pans costs around $1,000 I notice, as I too have gone that route (though I have also a glass bell jar in which to put them inside of for now.) and also got myself a non-working pump to take apart and see if I can fix.

A cheap TIG in Australia can be gotten for under five hundred Aussie dollars (less USD). Stainless welding is really quite civilised when compared to stick or MIG - much less spatter, the arc is quite nice ... but you do have to keep the joints close or use filler rod, because TIG on its own will not fill gaps. I have been TIG welding stainless in my job for about five years, mainly tiny stuff. I think it's the best form of welding there is. Laser is vastly over-rated in my opinion.

However, while much useful work can be done by the backyard workshop, I'd agree with the poster that what we really need is a fusion simulator, that can be distributed over a cluster like SETI@home, and which will give us some reasonable answers. The backyard polywell, like the backyard tokamak, is not a going concern. It has to be big to break even. Let's get a multithread sim underway ...

Regards,
Tony Barry

Would you recommend the cheapest TIG one can get, or something more beefy for fusion work ?

If all you are doing is TIGging thick stuff, then a cheapie is AOK. If you are doing thin stuff, then the more expensive boxes will run lower amps, have other cool stuff like high frequency start, programmable current up-down during the weld, an end-of-weld current droop to minimise crater forming, etc. Also the cheapies are monolithic - if they break, parts are generally nonexistent. Better brands have spares.

Zixinus

After typing for an hour the response to your questions and providing you with the experiment directions, it's all gone. I guess the server logon time expired. So I'll do it again when I have more time.
By the way, the answer to both questions is yes! It can be done and if you perform the experiment the way I instruct, you will be able to do it to for under $100.

I find it useful to write in notepad and save it before posting a long reply via online forums due to this timeout issue, either that or use an offline forum reader to post with

There probably are a few experiments that can be done without a vacuum chamber, but meaningful electron capture won't be one of them. Any plasma phenomena would be under the definition of Paschen Arc or similar discharges, and those are the bane of these machines. They are essentially caused by excess gas, where "excess" is basically more than 6 orders of magnitude below one atmosphere.

Things that are meaningful to work on in air:

Basic magnetic field strength mapping (to confirm theoretical calculations)

Strength and endurance testing of magnet support structures.

Cooling tests. I think Simon will agree ... make sure you can deal with heating issues BEFORE this thing goes in the expensive and very clean vacuum tank.

On the NASASpaceFlight site, we were discussing what it would take to design heat shields for superconducting magnets in net power machines. Dr. B has proposed that reactors up to about 6 GW might be possible, and the natural reaction is to wonder what happens when 10-20% of that awesome amount is intercepted by the magrids. After bringing up the fact that this power level is comparable to the output of one Space Shuttle Main Engine (SSME), it occurred to me that it might be possible to test cooled shields for magnets using rocket fuel burned at the center of a magrid in air.

And never underestimate the value of such a device as a hands-on (careful of wristwatches) demonstrator. Both for education and familiarization, and as a dog and pony show.