A gyrotron cavity interaction simulation approach

Microwave generation in a gyrotron occurs within the interaction cavity, where a high-energy electron beam resonates with a transverse electric mode of the cylindrical cavity. Numerical tools are essential for designing and analyzing cavity operations, with the gyro-average approach traditionally fulfilling this role. This paper introduces an alternative model for fast and accurate simulation of the interaction cavity. Two innovative methods are proposed for calculating electron beam dynamics: the first employs a perturbation technique, while the second utilizes a particleless approach by expanding beam properties in a Fourier series. A specialized code has been developed based on this novel framework. This paper provides a detailed overview of the simulation model, its implementation, and initial results obtained using the new tool. • A hybrid modal-nodal model solves the wave equation in a gyrotron cavity. • A rotating frame enables fast, precise electron beam trajectory simulations. • Fourier analysis models the electron beam as a continuous flow. • Phaedra code has been developed based on the proposed numerical scheme. • A complete THz gyrotron cavity startup simulated using Phaedra code.