Abstract

Primordial magnetic fields (PMFs) offer a simple explanation for the origin of galactic magnetic fields as well as of the purportedly detected magnetic fields in cosmic voids. In the talk, I discuss how PMFs’ influence on structure formation can offer a complementary method to test for their existence. Specifically, I discuss how PMFs enhance the matter power spectrum on small scales (sub-Mpc). On scales relevant to galaxies and black holes, I show that PMFs can significantly enhance the baryon fraction in halos as well as the abundance of halos. Next, I show that on scales below the baryon Jeans scales, PMFs can enhance dark matter power spectrum purely by gravitational influence. I conclude by arguing how search for dark matter minihalos can potentially provide the most sensitive probe for PMFs.