Re: Static Gap question.

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br> 

Tesla list wrote:

 > Original poster: "Hydrogen18" <hydrogen18-at-hydrogen18-dot-com>
 >
 > Corona at 300 Volts? Is it not visible to the human eye? Or is it just very
 > small amounts( I know that all surfaces produce corona at any voltage).

Actually, breakdown in air doesn't occur when the potential difference
between the electrodes is below 340 V, no matter what is the distance
between them or the air pressure. This comes from "Paschen's law", that
although derived with XIX century instrumentation, appears to hold.
A sharp point with a potential of more than 340 V above its surroundings
shall produce some corona. I am not sure of how much is necessary for
clearly visible corona.

The rule is quite strange, however.
At 340 V, a sphere with a surface electric field of 30 kV/cm would
have a radius of 340/3e6 = 0.11 mm. Too large for quantum effects.

Antonio Carlos M. de Queiroz