Terahertz-Range High-Order Cyclotron Harmonic Planar Gyrotrons with Transverse Energy Extraction

We develop a multi-mode time-domain model for theoretical description of mode competition in a planar gyrotron with sheet beam of rotating electrons and transverse energy extraction. Within the frame of this model, we demonstrate an improvement of mode selectivity and power increasing in the case of excitation of high-order cyclotron harmonics in terahertz-range planar gyrotrons. The obtained results are confirmed based on direct 3D PIC (particle-in-cell) simulations.