Unipolar Arcing on the Cathode Surface of a High Voltage Diode

The idea of electron emission from an exploding cathode whisker has been reported on many times by various research groups. However, since the reported estimates of current density from the cathode spots vary widely over several orders of magnitude, it is clear that the actual mechanism of explosive emission is not well understood. Plasma surface interaction via unipolar arcing can be shown to be able to supply the necessary current density to initiate explosive emission. Joule heating of the whisker by unipolar arcing is much greater than for either field emitted or space charge limited current flow. It has now been shown experimentally that unipolar arcing occurs not only in a laser induced plasma surface interaction, but also in a vacuum diode discharge at the cathode surface. the unipolar arcing process forms the initial breakdown plasma in each case. Keywords Unipolar arcing Laser surface interaction Whisker explosion Theses.