Multi Cylinder Cathode Fusor

[Frank Sanns]

In the past, I have done many different configurations of grid structures. With all of the work with the small fusors with a cylinder cathode, it had me thinking about the plasma behaviors. I decided on a design that would let me study what is happening with the plasma and ultimately with the neutrons.

If one is good, more are better. Well, maybe.

To study the plasma dynamics I am beginning work on a four cylindrical grid configuration. I have two HV feedthroughs on my chamber so I decided to configure it with alternating wirings. The first and the third are wired together and the second and fourth are wired together.

It is configured to run all four at HV together. It can also run alternating ones grounded or floating. It can also run two at negative HV and two at positive HV. Alternating HF frequencies are also a possibility. It gives a great deal of flexibility to study what is occurring.

In addition, those that know me know that I do not like symmetry when I am studying plasma. Hence the choice of four cylinders to the terminal one in most configurations will not have the same potential/polarity as the one at the opposite end.

Here is the first picture at only mechanical pump pressure with air. The top and third cylinder down elements are grounded. The second and fourth from the top are at -3 KV. I am still shaking down the prototype design yet but I figured I would share a glimpse of what is coming.

[Richard Hull]

Interesting... I look forward to more results on your ideas here. Welcome back to the fusor activities and operational regimes.

Richard Hull

[Jon Rosenstiel]

Should be interesting... and exciting too. Good on ya, Frank.

JonR

[Jim Kovalchick]

Looks like you made an Einzel lens. How did you determine the spacing?

[Frank Sanns]

There are more factors being looked at than I have mentioned. Based on work from those of you that have run the cylinder cathodes, many questions arise.

The cathodes are 7/8" long, 1/2" ID. The inside distance between end caps of the chamber are 15.5".

Alignment seems to be very critical but with what, the end plates or the symmetry of the field within the chamber. It would be especially true in the small fusors. So my spacing of the adjacent cathodes is a study in those fields that are not really near field and not really far. One question that nags at me is the length of the "beam" as it seems unstoppable over a great distance despite grounded elements being in its path. The full 15.5" of chamber interior should help visualize what is going on.

So to answer your question, the spacing and sizes were based on getting as many different measurements of near and far behaviors.

The experiments will present themselves as the work continues. My goal is to run this prototype under high vacuum to get some results. If this crude prototype starts to give up some good info then I will know the design for the fully machined high output version.

[Artem Artemov]

This is very cool! I demand to continue)))