Decay and Regeneration of the Galactic Magnetic Field in the Presence of Magnetic Monopoles

The resonant character of magnetic field damping by moving magnetic monopoles allows the field to survive indefinitely when the monopole plasma frequency is sufficiently large, even if the field is immersed in a conducting plasma. Dynamo growth of galactic field can still occur on time scales ∼${10}^7$-${10}^8$ yr in the presence of a halo composed of monopoles. A linear stability analysis suggests that a monopole's mass is $m\sim {10}^{18}$ GeV/${\mathit{c}}^2$ and that the monopoles should have an anisotropic flux ∼1 ${\mathrm{m}}^{-2\mathrm{}}$ ${\mathrm{yr}}^{-1\mathrm{}}$ ${\mathrm{sr}}^{-1\mathrm{}}$.