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Re: sparks



"John S. Denker" wrote:

At 06:55 PM 2/17/01 -0800, Ben Crowell wrote:


I'm missing something here? I thought it was more like ~ 15 V.

http://wulff.mit.edu/pt/pert9.html

bc


On a related note, does anyone know how strong a field is
required to ionize air, and how strongly this depends on
humidity?

It's about 3 megavolts per meter. You can guestimate this answer based on
the previously-described model: an ion needs to pick up enough energy
between collisions to have a fair chance of ionizing whatever it
hits. That requires a field strength on the order of a fraction of a volt
per mean-free-path.

The breakdown field depends strongly on density, and not very strongly on
humidity.