Novel computer model for simulation of backward wave oscillators

Summary form only given. In recent years, remarkable advance in the experimental studying and understanding of operation of relativistic backward wave oscillators (BWO) has been made. For adequate theoretical treatment of experiments and further BWO optimization a rigorous computer model is required, which is capable of accounting for ac and dc space charge effects, "full wave" representation of fields and self-consistent mode coupling at the ends and within the resonator. All foregoing theoretical models, as far as we know, treat the above mentioned effects non-self-consistently, so that some disparities originate in predicted and measured data. The novel theoretical model being free from such deficiencies has been developed using the singular integral equation method. The first results obtained for the simplified (linear) model of the beam allow us to accurately describe the phenomenon of operating frequency locking (which was observed over wide range of diode voltage) and to understand its physical sense. It appears to be caused by diffractional broadening of spatial harmonics, which is also taken into account in our model.