Excitation of Dust-Acoustic Wave Turbulence in Saturn’s Magnetosphere

Linear and nonlinear processes that can play an important role in the plasma of Saturn’s magnetosphere and are associated with the presence of dust are analyzed. Excitation of dust-acoustic wave turbulence caused by the interaction of heavy ions and “cold” electrons of Saturn’s magnetosphere with charged dust is described. It is demonstrated that dust-acoustic waves can be driven in the range of distances between approximately one and a half to two planet radii from the center of Saturn. The induced scattering of the dust-acoustic waves by dust particles represents the primary nonlinear process affecting their spectrum. The wave spectrum is determined by the balance of the linear and nonlinear effects. It turns out that the ratio of the energy density of the dust-acoustic waves to the energy density of plasma particles is relatively large, which is indicative of the dust-acoustic wave turbulence playing an important role in Saturn’s magnetosphere and the possibility of the generation of the dust-acoustic nonlinear waves, such as solitons or periodic nonlinear waves.