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RE: 20 joules at 100 bps vs 4 joules at 500 bps

Original poster: "Denicolai, Marco" <Marco.Denicolai@xxxxxxxxxxx>

Hello Antonio, all,

Back from vacation I noticed my ugly typos... Of course ALL my given field strength were intended to be kV/cm.

- small gaps: 30 kV/cm
- medium gaps: 5 kV/cm (not kV/m)
- long gaps: 1 kV/cm (not kV/m)

Sorry for the mess...

BR



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From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Fri 8/5/2005 9:04 AM
To: tesla@xxxxxxxxxx
Subject: Re: 20 joules at 100 bps vs 4 joules at 500 bps

Original poster: "Antonio Carlos M. de Queiroz" <acmdq@xxxxxxxxxx>

Tesla list wrote:

>Original poster: "Denicolai, Marco" <Marco.Denicolai@xxxxxxxxxxx>
>Hello Jim, all,
>Based on my readings there are 3 different situations for breakdown:
>- small gaps (some cm), Efield required 30 kV/cm, breakdown with
>avalanche (Townsend).
>- medium gaps (< 1 m), Efield required 5 kV/m, breakdown with stable
>streamers and final jump.
>- large gaps (> 1 m), Efield required only 1 kV/m, breakdown with
>leader-streamer phases and final jump.
>These phenomena are very well documented, although usually with
>different names and in not such a clear manner. So, for a 2 m
>breakdown you need a 30 kV/m on the toroid surface, then at least
>some 5 kV/m within 1 m from it and the rest of the travel will
>succeed if 1 kV/m can be ensured.

This is interesting. In looking at sparks between two balls, there is
evidently a distance where sparks cease to occur, even with corona at
the spheres still occurring. A certain minimum required electric field
in the space between the terminals is evidently required.
But values as 5 kV/m seem too low, at least for relatively short sparks.
For example, I have an electrostatic machine that can produce sparks
with up to 16.5 cm between 2.4 cm spheres. I can simulate this in the
Inca program, that predicts a breakdown voltage of 66.5 kV. Charging
the balls to +/- 33.25 kV, the electric field exactly between the balls
has a minimum of 96 kV/m. So, for sparks in this range, apparently
something as 100 kV/m is required.
But this is of a single spark. RF sparks, that grow progressively,
may need less.

Antonio Carlos M. de Queiroz