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Debris disks are readily detectable tracers of embedded planetary systems however comma their complex internal structures are often challenging to interpret as most debris disks do not harbor known exoplanets. The prototypical debris disk around Beta Pic and its two relatively short-period super-Jupiter planets offer a unique laboratory for studying planet-disk interactions. Five mechanisms have been identified through models in which Beta Pic b may shape the complex disk structure and may perturb planetesimals into an inclined orbit comma giving rise to the secondary disk discovered with HST. Structures shaped by the planet.s resonances can introduce large-scale azimuthal asymmetries in the disk that orbit on timescales similar to that of the planet (virgul18 yr). With STIS images from 1997 and 2012 a uniquely long baseline is available for identifying the temporal evolution of the disk comma which is predicted to evolve on comparable Keplerian timescales. We propose to revisit and continue monitoring the Beta Pic disk with STIS to characterize the temporal evolution of the disk. By repeating the earlier observations we will detect variations as small as 1% at 0.5d_comma. In comparison comma models of radiation-pressure driven small grains freed from planetesimals trapped in resonance with the planet predict variations up 300% in this component. We will identify disk structures and dust grain populations that are a result of interactons with the two giant planets comma directly testing models explaining the disks. complex structure. These observations will provide an entirely new set of constraints on the 3D structure and dynamics of the only known disk-planet system where such measurements are possible.