Electron avalanche model of dielectric-vacuum surface breakdown

The model assumes that an "initiating event" results in positive ions on the surface near the anode and reverses the direction of the normal component of electric field so that electrons in vacuum are attracted to the dielectric locally. A sequence of surface electron avalanches progresses in steps from the anode to the cathode. For 200 kV across 1 cm, the spacing of avalanches is predicted to be about 13 mu m. The time for avalanches to step from the anode to the cathode is predicted to be about a nanosecond. (C) 2007 American Institute of Physics.