The multipactor discharge in crossed fields in a rectangular waveguide of the 3-cm wavelength band

We present the results of an experimental study of a single-sided multipactor discharge in crossed fields in a rectangular waveguide of the 3-cm wavelength band. The discharges with the electron drift on the wide wall of the waveguide along and across the waveguide axis in a standing wave and a traveling wave are studied. It is found that the multipactor discharge is capable of developing and absorbing radiation intensively, if the microwave field is not uniform, and multiplying electrons can have only a limited number (20–30) of sequential collisions on the surface intervals between the field nodes. The specific power absorbed in the discharge amounted to several kilowatts per square centimeter for a microwave field of about 30 kV/cm. The obtained data allow one to predict the existence of the discharge in the waveguides and cavities of the devices, in which spatially developed volume modes are deployed to transport higher-power radiation including the modes with complicated structures of the microwave field, where the azimuthal distance between the field nodes is comparable with the length, at which the discharge saturates. The evaluations made show that the density of electrons in the discharge is approximately equal to the critical value for the used radiation frequency. The demonstrated properties of the multipactor discharge can be employed to develop absorbing devices and control the cavity properties.