Reduced Plasma Frequency Calculation Based on Particle-in-Cell Simulations

We propose a scheme to calculate the reduced plasma frequency of cylindrical-shaped electron beam flowing inside cylindrical tunnel, based on results obtained from Particle-in-cell (PIC) simulations. In PIC simulations, we modulate using two parallel, non-intercepting, closely-spaced grids which are electrically connected together by single-tone sinusoidal voltage source. The energy and current distributions along length tunnel monitored after system is operating at steady-state. build matrix describing beam's dynamics, estimated fitting 2x2 that best agrees with first order differential equations govern physics-based system. Results compared theoretical Branch Mihran model, typically used compute reduction factor in such systems. Our method shows excellent agreement however, it also general. can be potentially utilized determine frequencies beams propagating differently-shaped tunnels, where no model yet exists, as case or elliptical metallic cylindrical, square, cross-section. It applied composed multiple streams.