Development of simulation tools for design of multiple beam folded waveguide TWTs

NRL large signal design codes have been developed recently to be suitable for accurate simulations of multiple beam traveling wave tubes (MB-TWT). MB-TWTs are attractive novel devices with enhanced power-bandwidth characteristics. However, they are more vulnerable to spurious oscillations than single beam TWTs. The results of performance and stability analysis of MB-TWTs with 3D EM codes, NRL 3D PIC code Neptune and recently developed 1D and 2.5D design codes TESLA-FW and CHRISTINE-FW are presented and discussed.