Study on explosive emission characteristics of the silicon carbide modified graphite cathodes with varied morphologies

Abstract

Explosive emission cathodes are extensively used in high power microwave sources. Growing requirements are highlighted in the performance of the explosive emission cathode with the development of the high power microwave technology. In order to improve the emission properties of the graphite cathode, modifications using SiC particles or whiskers are carried out by the in situ chemical vapor reaction method. The experiments demonstrate that SiC whiskers accelerate the explosive emission turn-on speed of the graphite cathode for large field enhancement factors and improve the emission uniformity due to the surface flashover plasma generation mechanism. SiC particles increase the emission capability of the graphite cathode, possibly corresponding to the dielectric properties of SiC particles. These results suggest that the SiC whiskers modified graphite cathode is suitable for applications under low magnetic field and large emission area conditions, while the SiC particles modified graphite cathode has a brighter application prospect in the long-time stable operation.