Zusammenfassung
Pitch-angle scattering rates for cosmic-ray particles in magnetohydrodynamic
(MHD) simulations with imbalanced turbulence are calculated for fully evolving
electromagnetic turbulence. We compare with theoretical predictions derived
from the quasilinear theory of cosmic-ray diffusion for an idealized slab
spectrum and demonstrate how cross helicity affects the shape of the
pitch-angle diffusion coefficient. Additional simulations in evolving magnetic
fields or static field configurations provide evidence that the scattering
anisotropy in imbalanced turbulence is not primarily due to coherence with
propagating Alfven waves, but an effect of the spatial structure of electric
fields in cross-helical MHD turbulence.
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