Re: Toroid Design

["Jim Lux" <jimlux-at-jpl.nasa.gov> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

> I looked at this problem some time ago, but didn't finish the research.
> What is needed is how to compute the maximum electric field around
> a toroid rised to a given potential. If this field reaches about
> 30 kV/cm, breakout will surely occur. 
> This problem was certainly already solved, I'm just not sure if 
> in closed form.

Exactly... There isn't a closed form, just like for a sphere gap, although
one would think that there is some semi-empirical formula, but I haven't
run across it.

I'd take the minor radius as the limiting factor, especially considering
that most folks will have surface imperfections that will limit the actual
maximum field.

BUT, to really consider this problem (and yesterday's post got me
thinking), you also need to factor in the distributed inductance to feed
the streamer growth.... Or at least do enough analysis to show it's
insignificant.

> The members that have electric field solvers could prepare a table
> or a formula showing how the maximum electric field
> is related to the potential for several major an minor radii of
> a toroid. This would be useful, even ignoring distances to
> walls and the presence of a coil below.
> 
> Antonio Carlos M. de Queiroz
> 
> 
> 
>