Milli-magnetic monopole dark matter and the survival of Galactic Magnetic Fields

Dark sectors with Abelian gauge symmetries can interact with Standard Model particles through kinetic mixing. If magnetic monopoles exist in the dark sector and form a sizable component of dark matter, they can affect the survival of the Milky Way's Galactic magnetic field. In this talk I will present results that revise and extend this "Parker Bound" on galactic magnetic energy loss to milli-magnetic monopoles, which leads to the strongest existing constraints on these particles, satisfying our halo ellipticity bounds, over a wide range of dark magnetic monopole masses.