Investigation of virtual cathode generated by a tungsten emissive probe in a vacuum

Abstract

The virtual cathode characteristics (the potential barrier and the spatial size) generated by a tungsten emissive probe are investigated in a vacuum using the one-dimensional theory of the virtual cathode developed by us. In the calculation principle of the virtual cathode, the effective filament area for electron emission is treated with different models. Using the calculation principle, the potential barrier and the spatial size of the virtual cathode are calculated with the tungsten emissive probe heated from the beginning of electron emission to the end of the filament life. The calculated results show that the potential barrier of the virtual cathode generated by the tungsten emissive probe can reach several volts, the spatial size is on the order of centimeters, and the corresponding electric field is on the order of kilovolts per meter.