Contributed Talk - Splinter ISM

Thursday, 24 September 2020, 12:06   (virtual room F)

Diffusion and dispersion in anisotropic magnetohydrodynamic turbulence

J. Pratt, A. Busse, W.-C. Müller
Georgia State University, University of Glasgow, TU Berlin

Magnetohydrodynamic (MHD) turbulence structured by a large-scale magnetic field is an essential aspect of interstellar or interplanetary plasmas. Here we investigate diffusion and dispersion in anisotropic MHD turbulence. We adopt the Lagrangian viewpoint, the natural point of view to study diffusion, and construct statistics based on the trajectories of Lagrangian tracer particles. From the motions of these tracer particles, we produce Lagrangian statistics such as single-particle diffusion, two-particle dispersion, and velocity autocorrelations. We also demonstrate new Lagrangian statistics developed to understand anisotropic turbulent dispersion. Simulation results will be presented that are performed using grid sizes up to 2048^3. Diffusion and transport processes in turbulent plasmas constitute fundamental astrophysical problems; a clear understanding of these processes is needed in order to produce improved theoretical models for the diffusion and transport of energetic particles, including cosmic rays.