Three-dimensional particle-in-cell analysis of beam-wave interaction in a multi-section severed helix TWT

Three-dimensional particle-in-cell analysis of beam-wave interaction was carried out in MAFIA for a multi-section severed helix traveling-wave tube. The severloss was modeled by considering the carbon-coated helix-support rods as lossy dielectric rods having finite conductivity as a step function corresponding to the circuit attenuation constant along the taper-profiled loss in the sever-loss region. The analysis was benchmarked against published 1D large-signal analysis results and close agreement was observed.