  We consider the time evolution of the electric and magnetic field operators
for a two-level atom, interacting with the electromagnetic field, placed near
an infinite perfectly conducting wall. We solve iteratively the Heisenberg
equations for the field operators and obtain the electric and magnetic energy
density operators around the atom (valid for any initial state). Then we
explicitly evaluate them for an initial state with the atom in its bare ground
state and the field in the vacuum state. We show that the results can be
physically interpreted as the superposition of the fields propagating directly
from the atom and the fields reflected on the wall. Relativistic causality in
the field propagation is discussed. Finally we apply these results to the
calculation of the dynamical Casimir-Polder interaction energy in the far zone
between two atoms when a boundary condition such as a conducting wall is
present. Magnetic contributions to the interatomic Casimir-Polder interaction
in the presence of the wall are also considered. We show that, in the limit of
large times, the known results of the stationary case are recovered.
