  The nature of vertical heating of disk stars in the inner as well as the
outer region of disk galaxies is studied. The galactic bar (which is the
strongest non-axisymmetric pattern in the disk) is shown to be a potential
source of vertical heating of the disk stars in the inner region. Using a
nearly self-consistent high-resolution N-body simulation of disk galaxies, the
growth rate of the bar potential is found to be positively correlated with the
vertical heating exponent in the inner region of galaxies. We also characterize
the vertical heating in the outer region where the disk dynamics is often
dominated by the presence of transient spiral waves and mild bending waves. Our
simulation results suggest that the non-axisymmetric structures are capable of
producing the anisotropic heating of the disk stars.
