The impact of nonlinear Landau damping on cosmic ray streaming and the role of external turbulence
The study investigated whether nonlinear Landau damping (NLLD) naturally stops cosmic ray streaming instabilities or if external turbulence is required. Simulations showed NLLD is generally inefficient for self-generated waves, and its effectiveness depends on the presence of external wave power. The authors conclude that NLLD is not an intrinsic saturation mechanism but rather its impact relies on the interplay between CR-driven and externally seeded turbulence.