Alysson Gold, Stanford University, USA
Modeling the non-linear interaction between intense charged particle beams and electromagnetic fields in beam-based radiation sources, from klystrons to free electron lasers, has historically been addressed through semi-analytical models. Through recent advances in manufacturing and materials science, we can now realize structures and interaction topologies which are vastly more complex than in current devices – unintuitive configurations with the potential to overcome traditional limits in interaction efficiency and output power. These device concepts lie beyond the assumptions of semi-analytical models, however. To address this issue, we present a highly general modeling approach which applies abstract concepts from Lagrangian mechanics, classical and quantum field theory and differential geometry to the concrete challenge of full-wave electromagnetic finite element analysis. Through this unique field theory perspective, we overcome several open problems in steady-state beam-wave modeling, from the interpolation of the current density from particle trajectories (where we demonstrate an 80x improvement in accuracy over existing state-of-the-art approaches), to the revival of the traditional nodal finite element framework for the solution of electromagnetic fields.