ITC Special Seminar - Alex Lazarian (UW Madison)


Friday, November 18, 2016, 2:30pm to 3:30pm



"Superdiffusion and Streaming of Cosmic rays"

The propagation of cosmic rays (CRs) is usually described as a diffusion process. This is frequently not right, however. The propagation of the CRs perpendicular to the magnetic field is governed by the Richardson dispersion and this induces superdiffusive behavior for the propagation of the CRs over distances less than the turbulence injection scale. The latter is about 100pc for the Milky Way. I will discuss how this changes the accepted picture of CR acceleration. Another point that I am going to discuss in the effects of turbulence on the streaming instability in the Galaxy. This process was quantified for transAlfvenic turbulence by Farmer & Goldreich (2004) who concluded that it was not possible to reconcile the efficiency of turbulent damping and the observed degree of CR isotropy. I will show how this paradox can be resolved.