  We numerically examine mixtures of circularly moving and passive disks as a
function of density and active orbit radius. For low or intermediate densities
and/or small orbit radii, the system can organize into a reversible partially
phase separated labyrinth state in which there are no collisions between disks,
with the degree of phase separation increasing as the orbit radius increases.
As a function of orbit radius, we find a divergence in the number of cycles
required to reach a collision-free steady state at a critical radius, while
above this radius the system remains in a fluctuating liquid state. For high
densities, the system can organize into a fully phase separated state that is
mostly reversible, but collisions at the boundaries between the phases lead to
a net transport of disks along the boundary edges in a direction determined by
the chirality of the active disk orbits. We map the dynamic phases as a
function of density and orbit radii, and discuss the results in terms of the
reversible-irreversible transition found in other periodically driven
non-thermal systems. We also consider mixtures of circularly driven disks and
ac driven disks where the ac drive is either in or out of phase with the
circular motion, and find a rich variety of pattern forming and reentrant
disordered phases.
