  The effect of a magnetized plasma on the resonant photoproduction of axions
on the electromagnetic multipole components of the medium, $i \to f+a$, has
been considered. It has been shown that the axion resonant emissivity, due to
various reactions involving particles of the medium, is naturally expressed in
terms of the emissivity of the photon $\to$ axion transition. The number of
axions produced by the equilibrium cosmic microwave background radiation in the
magnetar magnetosphere has been calculated. It has been shown that the resonant
mechanism under consideration is inefficient for the production of cold dark
mass.
