  Scorpius is a new multi-pulse linear induction accelerator (LIA). It is
presently planned for Scorpius to accelerate four 2-kA electron pulses to 20
MeV from an injected energy of 2 MeV. The goal of Scorpius is to deliver a
multi-pulse electron beam with quality sufficient for use in flash radiography
of large-scale explosively-driven experiments. Beam physics has a profound
effect on the quality of multi-pulse radiographs. Beam halo or asymmetry causes
emittance growth, which enlarges spot size, thereby degrading resolution. Beam
centroid motion due to instabilities is especially problematic. High-frequency
motion blurs the radiographic spot size, thereby degrading resolution.
Low-frequency motion causes pulse-to-pulse wandering of the source spot,
thereby degrading registration of successive radiographs. We use a wide range
of tools to investigate potential beam physics problems associated with
Scorpius. In addition to analytic theory and experimental data from our
operational LIAs, we use a number of reliable beam dynamics computer codes.
These include both beam envelope and particle in cell (PIC) codes.
