A question about treatment area vs Volume

Pretty much.

The field is more intense around the smaller inner pipe, so that's where most of the action will happen.

Coax set-ups are less fiddly, and have fewer spacers to with fewer options for the spacers to move around, but it's hard to get a lot of surface area,

So maybe a 6" or 7" inner pipe and a 8" outer pipe to get more area and just make it taller to get the required volume. Will calculate to see if what pipe sizes would be a reasonable height. Thanks, Mikek

This are thought-provoking questions. I think I would look up the design equations for an air-filled coaxial transmission line and go from there. In fact, I believe I have seen equations for the capacitance of a coaxial capacitor.

Anyway, good luck.

John

Here ya go...

Even though I'm looking at the equation, I still can't reconcile B/A and how it relates to the area of the inner electrode (pipe). Weak math background. But, I did note, that making the inner pipe larger and the length longer increases the capacitance, there is a limit where our square wave drive starts to have a long rise and fall time. (6MΩ series resistor to work the switch against.) We may just fall back on 60Hz drive instead of the variable frequency drive that we have now. Here's the calculator I used.

Ok, Mike -

The surface area of a cylinder is the perimeter times the length. So, in this case, they say the radius of the inner cylinder is a. The perimeter of the circle is the diameter of the circle times pi. So then the perimeter is 2*a*pi. Well, then the area of the inner tube is

Oh, I understood how to calculate the area of the inner pipe and I thought that might be the number to use for area/volume question. I just thought in the equation on the page you posted that the b/a should be b-a to get a distance between plates. But I'm not to concerned, I can put some numbers to it and see it work. Thanks, Mikek