  Understanding axial charge dynamics driven by changes in Chern-Simons number
densities is a key aspect in understanding the chiral magnetic effect (CME) in
heavy-ion collisions. Most phenomenological simulations assume that a large
amount of axial charge is produced in the initial stages and that axial charge
is conserved throughout the simulation. Within an (expanding) homogeneous
holographic plasma, we investigate the real-time axial charge relaxation
dynamics and their impact on the chiral magnetic current. Moreover, we discuss
the real-time interplay of the non-Abelian and the Abelian chiral anomaly in
the presence of a strong magnetic field. In the expanding plasma, the
Chern-Simons diffusion rate and thus the axial charge relaxation rate are time
dependent due to the decaying magnetic field. We quantify the changes in the
late time falloffs and establish a horizon formula for the chiral magnetic
current.
