  We investigate the chiral anomaly in a Floquet system under a time-periodic
electric field in (1+1) dimensions. Using the van~Vleck high-frequency
expansion, we analytically calculate the chiral current and the pseudo-scalar
condensate for massless/massive fermions and how they are balanced with the
topological charge. In the high-frequency limit, we find that finite-mass
effects are suppressed and the topological charge is dominated by the chirality
production. Our calculations show that the information about the chiral anomaly
is stored not in the static Floquet Hamiltonian but in the periodic kick
operator. The computational steps are useful as the theoretical foundation for
higher-dimensional generalization.
