wie geht das?

http://video.google.com/videoplay?docid=2669501183162419322&hl=en

can someone please explain?

Basicly I wonder whether it still would "work" in vacuum.
My reasoning is as following ... assume we somehow can take away
some of the electrons sitting on the stab. than the overall
charge would be positive and the moving part of this device
will raise .. well, when we shoot some x-rays at the device
the "missing" electrons must come from some source. Thus
I make the conclusion that x-ray ionize the air.

Some more ideas?