Vacuum Voltage Breakdown as a Thermal Instability of the Emitting Protrusion

Abstract

Breakdown by thermal instability of a field emitter is analyzed, taking into account the temperature dependence of field emission and of resistivity. Beyond a certain temperature the emission increases while the necessary field drops. It is shown that for a whisker-like emitter this instability occurs when the emitting tip is only several hundred degrees centigrade hotter than the bulk of the cathode.