Simulations of a Coaxial Multipactor Testbed

A well-documented effect of cosmic and solar radiation on TWTs used in satellites is the production of secondary electrons from the bombardment of incident particles and the resultant cascade and growth of these secondaries, which in turn leads to tube failure. Our work focuses on numerical simulation of gap closure in coaxial geometry due to the multipactor effect. The secondary electron yield (SEY) is dependent not just on material properties, but also on the geometric properties of the surface and of the tube, as well as the size of the interaction space and the operating frequency. We then focus on particle-in-cell simulations of a coaxial testbed that will generate data to develop advanced models that incorporate patterned surfaces, new source geometries, and new materials developed to suppress SEY. This paper presents preliminary results from our coaxial PIC simulations utilizing the CST Design Studio and Spark3D codes.