Impact of beam energy spread and emittance on the subterahertz overmoded surface wave oscillator

Effect of electron beam energy spread and emittance on the output performances from subterahertz overmoded surface wave oscillator (SWO) are numerically investigated in this paper by using a particle-in-cell (PIC) code added beam quality model. The 2.5D simulation results show that, the small energy spread and emittance have few influences on the device, while the axial mode competition appears with their increases, leading to the unstable output. When the actual beam quality in laboratory frame is considered, the overmoded SWO shows the merit of stability to certain extent. Accordingly, this device is adaptive for high frequency operation.