Multipactor discharge in circular waveguide window

Abstract

To study the multipactor effect on the surface of a circular waveguide window excited by the TE11 mode, the effects of the radius of the window, frequency, and style of polarization of the electromagnetic field and the reflection coefficient of the incident wave are examined in this paper using a Monte Carlo algorithm and theoretical analysis. The results show that the character of the multipactor is dominated by the longitudinal velocity of the secondary electrons, which is directly proportional to the square of their oscillatory velocity and inversely proportional to the phase velocity of the RF field. Either increasing the radius of the window disk or decreasing the field frequency leads to the aggravation of multipactor discharge. Moreover, applying the circularly polarized TE11 mode in a circular waveguide window generates electrons at a higher velocity normal to the window disk than that with linearly polarized TE11 mode transmission. In addition, the increase in the reflection coefficient of the incident wave imposes a longitudinal gradient force in the vicinity of the window disk, which also boosts the longitudinal velocity of the secondary electrons and degrades multipactor discharge upstream of the window box.