Frequency-Domain Analysis of Single-Surface Multipactor Discharge With Single- and Dual-Tone RF Electric Fields

This article presents the frequency-domain analysis of multipactor discharge on a single dielectric surface. We employ the multiparticle Monte Carlo simulation model in one dimension with adaptive time steps to obtain the temporal profiles of the normal electric field, which is due to surface charging that corresponds to the multipactor strength, induced by single- or dual-tone radio frequency (RF) electric fields acting parallel to the surface. We apply a discrete Fourier transform (DFT) to obtain the amplitude spectrum of the normal electric fields. It is found that for the single-tone RF operation, the normal electric field consists of pronounced even harmonics of the driving RF frequency. The strength of a harmonic component in the normal electric field depends on its frequency and the incident RF amplitude. An empirical relation between the strength and frequency of the harmonics and the input RF amplitude has been proposed. For dual-tone RF operation, spectral peaks are observed in the amplitude spectrum of the normal electric field at various frequencies of intermodulation product of the RF carrier frequencies. Pronounced peaks are observed at the sum and difference frequencies of the carrier frequencies, at multiples of those frequencies, and at multiples of the carrier frequencies. Empirical relations between the heights of different spectral peaks and the input RF amplitudes have been proposed.