  We discuss the formation of dark matter caustics, and their possible
detection by future dark matter experiments. The annual modulation expected in
the recoil rate measured by a dark matter detector is discussed. We consider
the example of dark matter particles with a Maxwell-Boltzmann velocity
distribution modified by a cold stream due to a nearby caustic. It is shown
that the effect of the caustic flow is potentially detectable, even when the
density enhancement due to the caustic is small. This makes the annual
modulation effect an excellent probe of inner caustics. We also show that the
phase of the annual modulation at low recoil energies does not constrain the
particle mass unless the velocity distribution of particles in the solar
neighborhood is known.
