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.