A time-domain 1D Kirchhoff-PIC code for coupled-cavity traveling wave tubes

Summary form only given, as follows. We developed a 1-d small/large signal Kirchhoff-PIC hybrid code for modeling coupled-cavity traveling-wave tube (CCTWT). The objective is to determine the interaction between the electron beam and cavities both in the linear and nonlinear regimes. A, small signal multi-frequency TWT code can provide a description of the power spectrum produced by a low frequency modulated beam. A large signal multi-frequency TWT code is required to study the nonlinear mechanism responsible for mixing the low frequency modulation with the high frequency carrier signal. Each cavity is modeled as a three-port equivalent Curnow circuit with R, L, C elements. The input/output ports of each Curnow element connects to the corresponding output/input port of the following element, while the third port, called the beam port, models the interaction between the cavity gaps and the beam. The voltage across the beam port and the current through it are solved self-consistently, and the beam space charge forces for all discrete modes are included via the standard PIC method.