chuck wrote:
My understanding is that a strong electric field ionizes the air and
leads to formation of a corona.

Yes, but according to the references, fairweather conditions are
not a strong enough electric field to cause corona in the absence
of some other energy source.

I can't comment on that, Cecil. I was trying to keep the geometry simple
with a single vertical wire.

Well, a single vertical wire would have its ground plane grounded
so it might also build up a charge between the inner coax conductor
and outer conductor from wind-driven charged particles. But wouldn't
a ball on top reduce the possibility of corona just like it does
on other vertical antennas?
--
73, Cecil http://www.qsl.net/w5dxp