Time simulation of the nonlinear wave-particle interaction in meters long traveling-wave tubes

TL;DR

This paper introduces a self-consistent Hamiltonian model and a symplectic multi-particle algorithm to simulate nonlinear wave-particle interactions in long traveling-wave tubes, enabling efficient time-domain analysis.

Contribution

It presents a novel Hamiltonian framework and a multi-particle simulation algorithm tailored for periodic structures like TWTs, including a reduction model for efficiency.

Findings

Efficient simulation of nonlinear wave-particle interactions in 3-meter TWTs.

Explicit expression for electromagnetic power in non-monochromatic regimes.

A 3D helix version of the reduction model is developed.

Abstract

We propose a multi-particle self-consistent Hamiltonian (derived from an N-body description) that is applicable for periodic structures such as traveling-wave tubes (TWTs), gyrotrons, free-electron lasers, or particle accelerators. We build a 1D symplectic multi-particle algorithm to simulate the nonlinear wave-particle interaction in the time domain occurring in an experimental 3-meters long helix TWT. Our algorithm is efficient thanks to a drastic reduction model. A 3D helix version of our reduction model is provided. Finally, we establish an explicit expression of the electromagnetic power in the time domain and in non-monochromatic (non-"continuous waveform") regime.