Energetic particle transport in a finite amplitude magnetosonic and Alfvenic turbulence is considered using Monte Carlo particle simulations, which involve an integration of particle equation of motion. We show that in a low-Betha plasma cosmic ray c
an be the most important damping process for magnetosonic waves. Assuming such conditions we derive the momentum diffusion coefficient for relativistic particles in the presence of anisotropic finite-amplitude turbulent wave field, for flat and Kolmogorov-type turbulence spectra. We confirm the possibility of larger values of a momentum diffusion coefficient occuring due to transit-time damping resonance interaction in the presence of isotropic fast-mode waves in comparison to the Alfven waves of the same amplitude.
