Stimulated emission of oscillators in the case of the application of a weak longitudinal electrostatic field

The physical mechanism of the effect of an electrostatic field on the resonance bunching of an ensemble of nonisochronous oscillators is examined in the case when the field is oriented in the direction of the free motion of the particles. An analysis is presented of the energy transfer between the oscillators and a low-amplitude high-frequency field in the presence of the electrostatic field. Characteristic functions are obtained which depend on resonance detuning and describe the effect of the electrostatic field on the energy transfer. The present analysis is pertinent to the description of processes in cyclotron-resonance masers.