Two surface multipactor with non-sinusoidal RF fields

Abstract

Two-surface multipactor with a Gaussian-type waveform of rf electric fields is investigated by employing Monte Carlo simulations and 3D electromagnetic particle-in-cell simulations. The effects of the full width at half maximum (FWHM) of the Gaussian profile on multipactor susceptibility and the time dependent dynamics are studied. The threshold peak rf voltage, as well as the threshold time-averaged rf power per unit area for multipactor development, increases with a Gaussian-type electric field compared to that with a sinusoidal electric field. The threshold peak rf voltage and rf power for multipactor susceptibility increase as the FWHM of the Gaussian profile decreases. Compared to sinusoidal RF operation, the expansion of multipactor susceptibility bands is observed. In the presence of space charge, a high initial seed current density can shrink the multipactor susceptibility bands. The effect of space charge on multipactor susceptibility decreases as the FWHM of the Gaussian profile decreases. Decreasing the FWHM of the Gaussian electric field can reduce the electron population corresponding to the strength of the multipactor at saturation, at fixed time-averaged input power.