A model for the pionic components of nuclear wave functions is obtained fro
m light front dynamical calculations of binding energies and densities. The
picnic effects are small enough to be consistent with measured nuclear dim
uon production data and with the nucleon sea. But the pion effects are larg
e enough to predict substantial nuclear enhancement of the cross section fo
r longitudinally polarized virtual photons for the kinematics accessible at
Jefferson Laboratory.