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The relativistic cosmic ray population has long been theorized as a promising energy source for galactic winds; however, the details of cosmic ray propagation and influence in turbulent, multiphase environments are complex and unclear, thereby impairing our understanding of galaxy evolution as a whole. In this talk, I will present magnetohydrodynamic (MHD) simulations of cosmic ray transport and impact in three instructive case-studies. First, I’ll present galaxy-scale simulations of cosmic ray driven winds from an LMC-like dwarf galaxy, showing how the efficiency of supernova-driven outflows depends on cosmic ray transport. Second, I’ll zoom in on an idealized interstellar medium, whose density inhomogeneities and collisional targets comprise an ’’obstacle course’’ for cosmic rays. I’ll show how cosmic rays navigate and exchange energy and momentum with this clumpy, highly resolved medium, focusing on implications for wind driving but also touching on an interesting discrepancy between galaxy evolution simulations and multiwavelength observations. Finally, I’ll expand these zoom-in simulations to include turbulence, probing cosmic ray energy loss/gain in the presence of compressive turbulent motions and revising canonical equations for turbulent reacceleration. |
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