Multipaction Leakage of RF Electronics in Vacuum With Particle-in-Cell Modeling

This work showcases a previously unexplored failure mode of RF electronics in a vacuum: electron leakage being emitted from cable or adapter defects during multipaction. This is novel in the sense that generally electrons are considered to be trapped and not escape during multipaction. This phenomenon is explored using a full-wave electromagnetics Particle-in-Cell simulation with secondary emissions yield boundary conditions and Lorentz Force equation. The theory is developed using multiple stages based on frequency cycle periods to describe the phenomena under various phase/polarity shifts. The paper explores multiple aspects of the manufacturing and integration process which could instigate or impact this effect. In particular a pseudo-microstrip mode is seen to cause the effect, which can occur from coplanar waveguide adapters, end-launch adapters or damaged cabling. The paper also explores manufacturing effects, such as source roughness and oxidization of copper, and their impact to secondary emissions yield.