Study of Electron Beam Profile in Staggered Double Vane W-Band Interaction Structure

In this paper, a simulation study of electron beam profile in staggered double vane W-band interaction structure of Backward wave oscillators (BWOs) has been performed using particle-in-cell (PIC) simulation software, OOPIC Pro. Plasma-assisted BWO, a category of vacuum electron devices (VEDs), serves as a promising candidate for generating high-power THz radiation [1]. The staggered double vane interaction structure acts as the slow wave structure (SWS) in the THz BWOs, facilitating the energy transfer from the beam of highly accelerated electrons to the RF wave. This implies that the electrons traveling through SWS play an important role in the generation of high-power THz radiation. Thus, for obtaining high output power in BWOs, an electron beam with high current density and high energy is required. The current density of the beam depends on the spatial distribution of electrons [2]. The distribution of the electrons is determined by the electron beam profile, representing the shape of the beam as a function of the applied voltage to the electron source and the pressure of the gas inside the VED [2]. Hence, it is necessary to study the electron beam profile in SWS to optimize its generation parameters as per the power requirements of the device. Therefore, a simulation study has been carried out on the beam profile at different applied voltage, beam current, and gas pressure values. This paper presents a comparative analysis of the beam profiles based on the simulation results obtained at different values of applied voltage (20 - 35 kV), beam current (1 - 20 A), and gas pressure (20 - 1 Pa) using OOPIC Pro.