[AlexN]

Well basically what is inside the vacuum chamber when the power is turned on.. O2, N2, AR and H2O. The high voltage grids will hopefully ionze the particles and electrostatic forces should accelerate the ions towards the high negative charge in the center causing a multitude of collisions. At these low energies the best I could really hope for I think would be an intense glow in the center of the chamber however with more power the "star in a jar" phenomenon is pretty impressive..

Wrt the power and risks involved, the potential energy is definitely on the lethal side of the gauge however it is 10kV @ 2.6mA.. With a suitable protection circuit and a good deal of care I believe it can be done safely.