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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