The narrow slit width not only enables the capillary feed, but, when combined with the sharp channel edges directly opposite the accelerator, also ensures that a high electric field strength is obtained near the slit exit. The liquid metal column, when subjected to this electric field, begins to deform, forming cusps (Taylor cones), which protrude from the surface of the liquid. As the liquid cusps form ever sharper cones due to the action of the electric field, the local electric field strength near these cusps intensifies. Once a local electric field strength of about 109 V/m is reached, electrons are ripped off the metal atoms. These electrons are collected through the liquid metal column by the channel walls, and the positive ions are accelerated away from the liquid through a gap in the negative accelerator electrode by the same electric field that created them.
