  Recently there has been significant interest in the macroscopic manifestation
of chiral anomaly in many-body systems of chiral fermions. A notable example is
the Chiral Magnetic Effect (CME). Enthusiastic efforts have been made to search
for the CME in the quark-gluon plasma created in heavy ion collisions. A
crucial challenge is that the extremely strong magnetic field in such
collisions may last only for a brief moment and the CME current may have to
occur at so early a stage that the quark-gluon matter is still far from thermal
equilibrium. This thus requires modeling of the CME in an out-of-equilibrium
setting. With the recently developed theoretical tool of chiral kinetic theory,
we make a first phenomenological study of the CME-induced charge separation
during the pre-thermal stage in heavy ion collisions. The effect is found to be
very sensitive to the time dependence of the magnetic field and also influenced
by the initial quark momentum spectrum as well as the relaxation time of the
system evolution toward thermal equilibrium. Within the present approach, such
pre-thermal charge separation is found to be modest.
