Monte Carlo simulation of the multipactor electron discharge on a dielectric surface

This paper presents a Monte-Carlo model to investigate the single-surface multipactor discharge and its high-power absorption on a dielectric surface in the presence of the RF and dc electric fields. By employing a novel method in the numerical implementation of the secondary electron emission, the susceptibility diagram is constructed; beam loading and its power absorption by the multipactor discharge are examined; meanwhile the temporal evolution of the multipactor is also studied. The simulation results show clearly that (1) a steady state multipactor can be built up from a very low density initial electron distribution and an oscillatory steady state can be achieved when the positive charge, left by the emission of secondary electrons, is capable to build a large enough dc electric field; (2) during the saturation state, the normal electric field and the number of electrons in flight oscillate at twice the RF; (3) the average power absorbed by the multipactor, strongly depending on material parameters, is on the order of 1% incident power or less. Based on these results, the mechanism of RF window breakdown under high-power microwave conditions is suggested and several useful guidelines to prevent or extinguish the multipactor are presented.