  We present deep HST/STIS coronagraphic images of the Beta Pic debris disk
obtained at two epochs separated by 15 years. The new images and the
re-reduction of the 1997 data provide the most sensitive and detailed views of
the disk at optical wavelengths as well as the yet smallest inner working angle
optical coronagraphic image of the disk. Our observations characterize the
large-scale and inner-disk asymmetries and we identify multiple breaks in the
disk radial surface brightness profile. We study in detail the radial and
vertical disk structure and show that the disk is warped. We explore the disk
at the location of the Beta Pic b super-jupiter and find that the disk surface
brightness slope is continuous between 0.5 and 2.0 arcsec, arguing for no
change at the separations where Beta Pic b orbits. The two epoch images
constrain the disk surface brightness evolution on orbital and radiation
pressure blow-out timescales. We place an upper limit of 3% on the disk surface
brightness change between 3-5 arcsec, including the locations of the disk warp,
and the CO and dust clumps. We discuss the new observations in the context of
high-resolution multi-wavelength images and divide the disk asymmetries in two
groups: axisymmetric and non-axisymmetric. The axisymmetric structures (warp,
large-scale butterfly, etc.) are consistent with disk structure models that
include interactions of a planetesimal belt and a non-coplanar giant planet.
The non-axisymmetric features, however, require a different explanation.
