Calculating multipactor susceptibility chart using a semi-analytic approach with improved accuracy

Abstract

We propose a semi-analytic approach to investigate the multipactor in parallel plate structures with improved accuracy. The effects of emission velocity and transit time of electrons are studied and their corresponding susceptibility charts are calculated. As a result, the proposed model covers more dynamics of multipactor. In calculating the susceptibility chart, we propose a decision-making process taking into account impact velocity, required voltage, and trajectory of electrons. Therefore, we obtain a more accurate susceptibility chart that excludes non-physical scenarios. Our investigation reveals a different mechanism of multipactor, where the transit time of an electron across the gap can be either shorter or longer than the conventional half-cycle of the RF signal. The extent of this deviation depends on the maximum emission velocity of the secondaries. With this deviation, we demonstrate that the multipactor evolves over broader practical situations occurring not necessarily within a half-cycle of the RF signal. Finally, we study the higher-order multipactor resonances and also calculate their susceptibility charts. We demonstrate an overlap between the susceptibility charts of different orders depending on the emission velocity of primary electrons. The discussions herein provide an insight into the underlying dynamics of the multipactor, which can be used for practical multipactor suppression methods.