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Re: Streamer models used with Terry's new program



Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Steve,

My first impression was to try the "mole" approach. I've been thinking about that and I'm beginning to think that approach can't model the "reach" of the toroid. Seems like with a voltage at breakout on the topload, the molecules in the vacinity of the topload have already been stressed close to the point of ionization and it will take very little extra energy to put them over the "edge". Likewise, with a large toroid (with long reach), molecules at some distance from the toroid will be closer to the edge than molecules at the same distance using a smaller toroid. Thus it would take more energy to ionize those molecules with the smaller toroid. What are your thoughts on this???

Gerry R

Original poster: Steve Conner <steve@xxxxxxxxxxxx>

Here's where it starts to get tricky. I thought of one possible simple way to do it. In chemistry handbooks you can find ionization energies for nitrogen and oxygen, ie so many kJ to ionise one mole of the stuff. Or maybe (since you're dealing in charge) you could use the Faraday constant, that says it takes 96500 (iirc) coulombs to singly ionise one mole of anything. Also you know one mole of any gas is about 22 litres at STP or whatever. So you could estimate what volume of gas gets ionized by a given amount of charge, and make some assumptions about how it's distributed (sphere, cone, fractal, whatever) to get a surface area and hence a capacitance.

Possible problems with the Faraday constant approach- It doesn't take impact ionisation into account (one loose electron- so one quantum of charge- can ionize several atoms) nor account for the fact that current might flow through previously ionized gas rather than creating fresh ions. I don't know enough about the physics of atmospheric pressure discharges to visualise how that would affect the result.