  The chiral magnetic effect (CME) is a phenomenon in which an electric current
is induced parallel to an external magnetic field in the presence of chiral
asymmetry in a fermionic system. In this paper, we show that the electric
current induced by the dynamics of a pseudo-scalar field which anomalously
couples to electromagnetic fields can be interpreted as closely analogous to
the CME. In particular, the velocity of the pseudo-scalar field, which is the
phase of a complex scalar, indicates that the system carries a global U(1)
number asymmetry as the source of the induced current. We demonstrate that an
initial kick to the phase-field velocity and an anomalous coupling between the
phase-field and gauge fields are naturally provided, in a set-up such as the
Affleck-Dine mechanism. The resulting asymmetry carried by the Affleck-Dine
field can give rise to instability in the (electro)magnetic field. Cosmological
consequences of this mechanism are also investigated.
