Cosmic-ray hydrodynamics: Alfv\'en-wave regulated transport of cosmic rays

Understand

Star formation in galaxies appears to be self-regulated by energetic feedback processes.

• Among the most promising agents of feedback are cosmic rays (CRs), the relativistic ion population of interstellar and intergalactic plasmas.
• In these environments, energetic CRs are virtually collisionless and interact via collective phenomena mediated by kinetic-scale plasma waves and large-scale magnetic fields.
• The enormous separation of kinetic and global astrophysical scales requires a hydrodynamic description.