Cosmic Ray Transport in Magnetohydrodynamic (MHD) Turbulence

by Huirong Yan (DESY)

Wednesday 20 Nov 2019, 11:30 → 13:30 Europe/Zurich

4/2-011 - TH common room (CERN)

The electromagnetic interactions with plasma turbulence is crucial for Cosmic ray (CR) physics, which is important, in turn, for many applications in Galactic dynamics as well as topics such as the indirect search for dark matter.  I would like to clarify some outstanding issues related to particle transport in realistic turbulent astrophysical environments.  We have carried out both analytical and numerical studies aiming at a theory-justified picture of the transport process based on the numerically confirmed modern understanding of MHD turbulence.  Our results challenge the conventional view on the function of Alfvenic turbulence and reveal instead the dominant role of compressible turbulence on CR transport, which is further supported by our recent observational study of interstellar turbulence. I shall address the issue of the transport of CRs, both from interaction with preexisting turbulence in Galaxy and self-generated waves and demonstrate that cosmic ray transport is inhomogeneous and CRs are scattered differently for low and high energy CRs.  I shall also show that cosmic ray cross field transport is diffusive on large scales and superdiffusive on scales less than the injection scale of turbulence.