Particle-in-cell simulations of parametric decay instabilities near the upper hybrid layer

Abstract

The particle-in-cell (PIC) code EPOCH is used to simulate parametric decay instabilities (PDIs) converting a 105 GHz microwave X-mode pump wave into electrostatic daughter waves at the upper hybrid (UH) layer of a fusion plasma in 1D. The resulting fields are analyzed, identifying modes in f -and k-space, and estimating their spectral power as a function of pump wave intensity. Both linearly and nonlinearly converted modes are identified and their characteristics agree with literature. A dipole approximation employed in literature appears to be unjust.