Am 03.12.2011 16:20, schrieb Horace Heffner:
I suggest that the dark zone at the tip of the needle is not due to a
vacuum there. It is more likely due to the average delay for
recombination of the ions and electrons. Electron recombination with
ions is likely what produces most of the light.
I believe there is a vacuum for these reasons:
1) I placed a charged needle 1-2 cm above a water surface. The air blow
makes a sharp, mm deep and mm wide hole into the water surface.
If I assume, that the air stream originates from the needle's tip, wich
is measured in µm, the blowing pressure and the repulsion at the needles
tip in a µm distance must be 100 to 1000 times stronger.
The sudden electrostatic acceleration of electrons and ions must create
a vacuum.
This experiment was done with some kV only. I had to turn the voltage
down to avoid sparks, because I had only 1 or 2 cm distance to the water.
In pressurized air the voltage can be some 100 kV.
2) The electrostatic repulsion is strong enough to drive the electrons
out of the metal.
I believe the force required for this must be many times stronger than
the air pressure.
A side note:
It is interesting that a positive needle blows and also a negative
needle blows.
One should expect that a negative needle would attract the nuclei and
repel the electrons and should suck instead blow.
This does not happen, both needles blow.
So I think, directly at the needles surface, if it is negatively
charged, there should be a vacuum, but not empty, the vacuum must
contain a dense electron cloud.
Peter
