Modeling with TESLA-family of 2.5D large-signal codes: predicting performance and stability of the experimental mm-wave TWTs

We present an overview of the results and current status of the developed at NRL TESLA-family of 2.5D large-signal codes (including the circuit-model based code TESLA-FW and impedance matrix Z based code TESLA-Z), which are suitable for modeling of Serpentine/Folded-waveguide TWTs. These codes have been successfully applied to predict performance of the developed at NRL experimental single-stage G-band and 2-stage W-band TWTs. More recent progress in the code's development resulted in creation of the code TESLA-Z based stability analysis framework, which has successfully predicted band-edge instabilities, observed in both TWTs at the beam-voltages above their operational values.