  We examine the dynamics of superconducting vortices with two-fold anisotropic
interaction potentials driven over random pinning and compare the behavior
under drives applied parallel and perpendicular to the anisotropy direction.
The number of topological defects reaches a maximum near depinning and then
drops with increasing driving force as the vortices form one-dimensional
chains. This coincides with a transition from a pinned nematic to a moving
smectic aligned with the soft direction of the anisotropy. The system is
generally more ordered when the drive is applied along the soft direction of
the anisotropy, while for driving along the hard direction, there is a critical
value of the anisotropy above which the system remains aligned with the soft
direction. We also observe hysteresis in the dynamics, with one-dimensional
aligned chains persisting during a decreasing drive sweep to drives below the
threshold for chain formation during the increasing drive sweep. More
anisotropic systems have a greater amount of structural disorder in the moving
state. For lower anisotropy, the system forms a moving smectic-A state, while
at higher anisotropy, a moving nematic state appears instead.
