  Our situation as occupants of the Milky Way Galaxy, which is currently being
bombarded by the Sagittarius dwarf galaxy, provides the opportunity to study
the process of the dynamical heating of a galactic disk in action. Using an
N-body simulation which follows the interaction of a dwarf galaxy similar to
Sagittarius with a parent similar the Milky Way, we map and quantify the
dynamical influences of various components on the evolution of the disc. The
accelerations in the plane from the satellite, dark matter halo and disk are
calculated for each snapshot, and then decomposed into Fourier series on
annuli. The analysis allows the separation and comparison of the scales of the
different influences over space and through time. Throughout the simulation
accelerations due to the satellite are only important around disk passages, but
are enhanced by the distortion of the dark matter halo. The interaction drives
disk asymmetries within and perpendicular to the plane. The self-gravity of
disk distortions increase in importance with time, eventually leading to the
formation of a bar. For our own Galaxy, at the present epoch, Sagittarius is
close enough to a plane crossing to motivate a search for its direct influence
on the disk at intermediate radii, while the distortion of the Milky Way's dark
matter halo should leave its imprint in the outer disk. These results suggest
fruitful directions to take to disentangle signatures of the ongoing
interaction and learn about the dynamical processes that are currently shaping
the Milky Way.
