Spectral Broadening of Ion Bernstein Wave Due to Parametric Decay Instabilities

The parametric decay instabilities (PDIs) of ion Bernstein wave with different input power levels are investigated via particle-in-cell simulation. It is found that the number of decay channels increases with the input power. Resonant mode–mode couplings dominate for a low input power. With increasing the input power, the nonresonant PDIs appear to dissipate the energy of the injected wave and give rise to edge ion heating. The generated child waves couple with each other as well as the injected wave and/or act as a pump wave to excite new decay channels. As a result, the frequency spectrum is broadened with the increase of the input power.