Reduction of crossed-field diode transmitted current due to anode secondary emission

The limiting current theory for planar crossed-field diodes has long been studied extensively for various emission energies and temperatures. However, experimental measurements of transmitted current have shown significant departure from theory. This paper attempts to explain the reduction in transmitted current from that expected in theory in terms of secondary electron emission created by electrons hitting the anode. It is proposed that the presence of the secondary electrons increases the charge density in the gap, thereby reducing the amount of current transmitted. A detailed secondary emission model is implemented in a particle-in-cell code to study current reduction. The effect of secondary electrons on charge density, and on the resultant electric field and potential is also presented.