Modeling of drive induced oscillations in a coupled cavity TWT

A new physics based model suitable for multi-frequency stability analysis of CC-TWTs has been developed and implemented in the CC-TWT design code TESLA-CC. The model describes the beam-wave interaction inside a beam tunnel in the presence of a frequency of input signal, a test frequency of expected drive induced oscillation (DIO) and combinational frequencies. The expanded code is capable of simulations of many factors contribute to onset of DIO such as a focusing magnetic filed, reflections from the ends of the structure due to mismatch, and two-dimensional (2D) beam dynamics in strong RF fields.