Particle-in-cell simulation for frequency up-conversion of high-power microwave in time-varying plasma

The frequency up-conversion of an electromagnetic wave in a time-varying plasma has been simulated in this paper with particle-in-cell (PIC) method, and it transformed a 2.45 GHz source radiation into a 130 GHz radiation with the power conversion efficiency of around 0.39%. We also studied the effects of the plasma parameters including the plasma density, the finite rise time of ionization and the width of plasma slab. It is concluded that the frequency up-conversion of the output wave was mainly affected by the plasma density, which was consistent with the theoretical results. In addition, the simulation showed that the energy of the output wave would be lager with the increase of the width of plasma slab, and the conversion efficiency of the output wave and spectrum were much better when the plasma rise time was shorter. A considerable 130 GHz radiation could be obtained with the plasma density of 21020 cm-3, the plasma thickness of 1 cm, and the plasma rise time of 0.04 ns.