Modeling a Relativistic Backward Wave Oscillator Using a 3-D Conformal Finite Difference Time Domain Particle-In-Cell Simulation

초록

A relativistic backward wave oscillator (RBWO) is one of promising devices for generating high-power microwave (HPM) for diverse applications ranging from plasma diagnostics to directed-energy systems. This study benchmarks the performance of an RBWO equipped with a helical slow-wave structure (SWS) using advanced three-dimensional (3-D) conformal finite difference time domain (CFDTD) particle-in-cell (PIC) simulations as implemented in VSim. A 500 kV, 5 kA relativistic electron beam is employed to interact with the SWS, producing coherent TM01 mode radiation with a peak RF power of 1 GW at 10 GHz. The 3-D CFDTD PIC simulation framework can better resolve the helical SWS and electron dynamics, addressing limitations of conventional 2-D methods and the simulation results provide more physical insights in capturing the beam-wave interaction, electron beam trajectory, power output, and field distribution. The benchmark results have been compared with the experimental and 2-D simulation results in the literature, providing comprehensive validation.

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