On the effectiveness of an orbictron using the resonance groove in a mirror plane

The calculations of HF-fields in the open resonator (OR) of a THz-range orbictron have been performed. It is shown that, as the OR immobile mirror has a rectangular resonance groove on the bottom of which a binary comb is arranged, one can increase, with the same Q-factor, a HF-field amplitude in the region of the sheet electron beam, at least, by a factor of 6.