Three-dimensional particle-in-cell modeling of terahertz gyrotrons with cylindrical and planar configurations of the interaction space

We perform 3D particle-in-cell simulations of terahertz gyrotrons with two different configurations of the interaction space. For a gyrotron with conventional cylindrical configuration of the interaction cavity, we demonstrate reasonable agreement between simulations and experimental results, including output frequency, structure of the higher-order operating mode (TE17,4), output power, and ohmic losses. For a novel planar gyrotron scheme with transverse energy extraction, a possibility of further increasing the oversized factor with the single-mode operation regime retained is shown. Frequency detuning by mechanical variation of the gap between waveguide plates is also demonstrated. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4799819]