A Multipactor Discharge in Crossed Fields Under the Conditions of a Combination of Two Waves with Close Frequencies

We study the multipactor discharge in crossed fields, specifically, a microwave electric field and a quasistatic magnetic field. The multipactor occurs under the conditions of superposition of two microwave pulses with close frequencies, which correspond to the three-centimeter wavelength range. Experiments in the rectangular waveguide demonstrate that the multipactor develops and exists in a wide range of differences in the signal frequencies, which covers on interval of up to 700 MHz. The specific power absorbed in the discharge is equal to several kW/cm², and the radiation is absorbed efficiently at both frequencies. When the signal power is initially insufficient to ensure the multipactor development, an additional signal at a close frequency allows one to switch the discharge, which absorbs microwaves efficiently, on and off. At a frequency difference of up to 40 MHz, the achieved switch-on time is about 100 ns. Switch-on of the second signal in the line with a resonator cavity, which has a frequency belonging to the cavity frequency band, also results in the discharge development and switches the cavity from the transition regime to the reflection regime.