  We have used 2D back-projection Doppler tomography as a tool to examine the
influence of gravitational and magnetic phenomena in interacting binaries which
undergo mass transfer from a magnetically-active star onto a non-magnetic main
sequence star. This multi-tiered study of over 1300 time-resolved spectra of 13
Algol binaries involved calculations of the predicted dynamical behavior of the
gravitational flow and the dynamics at the impact site, analysis of the
velocity images constructed from tomography, and the influence on the tomograms
of orbital inclination, systemic velocity, orbital coverage, and shadowing. The
H$\alpha$ tomograms revealed eight sources: chromospheric emission, a gas
stream along the gravitational trajectory, a star-stream impact region, a bulge
of absorption or emission around the mass-gaining star, a Keplerian accretion
disk, an absorption zone associated with hotter gas, a disk-stream impact
region, and a hot spot where the stream strikes the edge of a disk. We
described several methods used to extract the physical properties of the
emission sources directly from the velocity images, including S-wave analysis,
the creation of simulated velocity tomograms from hydrodynamic simulations, and
the use of synthetic spectra with tomography to sequentially extract the
separate sources of emission from the velocity image. In summary, the
tomography images have revealed results that cannot be explained solely by
gravitational effects: chromospheric emission moving with the mass-losing star,
a gas stream deflected from the gravitational trajectory, and alternating
behavior between stream state and disk state. Our results demonstrate that
magnetic effects cannot be ignored in these interacting binaries.
