Q&A with Joe Khachan about copper coil Polywell

4 01 2010
To gather more information on the Sydney copper coil Polywell, I emailed the project leader Joe Khachan with some questions:


Q) What journal will this research be published in?
A) We haven’t decided yet.


Q) When will that journal article be published?
A) We have not written it. We need to obtain some final results before publishing.


Q) Is your ceramic magrid made from off the shelf parts?
A) The formers for the coils are made from Teflon. This is readily available and easy to machine.


Q) Are the copper coils in your magrid at positive potential or ground potential?
A) They are floating. The coils are not running at high voltage. Moveover, they are made of enamelled copper wire so biasing them will not help. By floating I mean they are electrically isolated from the whole system. The cathode that produces the beam is negative with respect to the chamber. A better way to do this is to make the Bussard polywell, where the rings are biased positively. As I say, we are doing it in this way to understand some of the physics before committing ourselves to a final design. The way we are doing it enables changes to be made very quickly.


Q) Are you only injecting electrons at this point? no deuterons?
A) Yes, electrons. There is hydrogen background gas in order to produce electrons from it.


Q) Why is the electron beam entering the magrid at an angle instead of being aimed right in the center?
A)That was one particular experiment of many. Other experiments had the beam going in normal to the faces. One reason for the angle is so that the electron beam doesn’t touch the langmuir probe at the center. Other reason is to see if the depth of the well changes with angle of beam.


Q) How are you measuring the depth of the electron well?


Q) What are you using for your electron gun?
A) A metal cylinder (as shown in the photo) placed at -10 kV in a few millitorr of hydrogen gas will produce the beam that you see.


Q)  How deep was your vacuum prior to electron injection?
A) Our base pressure is 10^-3 millitorr but we operate at a few millitorr, so we are not replicating Bussard’s polywell exactly since he operated at lower pressures, but at a few millitorr we can gain valuable insights before committing ourselves to a more involved experiments.


Q) What are the dimensions of the magrid?
A) The dimensions we have are quite arbitrary and are unlikely to produce any substantial fusion at this stage since the well may not be deep enough. However, the space between the inner faces of the spools is about 5 or 6 cm – very small.



4 responses

4 01 2010
Tweets that mention Q&A with Joe Khachan « Prometheus Fusion Perfection -- Topsy.com

[…] This post was mentioned on Twitter by famulus, Tree Lobsters!. Tree Lobsters! said: RT @famulusfusion: Q&A with Joe Khachan about copper coil Polywell: https://prometheusfusionperfection.com/2010/01/04/qa-with-joe-khachan/ […]

6 01 2010
insulated copper wire

Looks like a nice affordable way of building a low voltage polywell device. Arcing would be a problem at higher voltages needed for fusion, but lesser voltage would be enough to study plasma dynamics. I note the spacing between coils is much less than WB-6, which suggests losses at those cusps would be huge.

5 06 2010
Evan Mayo

I just found this page and read the interesting build.

Though I do see possibly one gross error.

It seems that the metal screws used may further impact the magnetic fields. Rather than stainless steel screws you may want to use nylon or plastic or anything non-conductive or electrically neutral non-metal.

Then in the test stage ramp up the voltage slowly to see if the screws will hold when the magnetic fields are generated.

Have you looked at the gauss fields?

5 06 2010

I will replace the screws on the coil formers with stainless steel, just had those laying around.

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