Bow shocks, bow waves, and dust waves. II. Beyond the rip point
  Dust waves are a result of gas-grain decoupling in a stream of dusty plasma
that flows past a luminous star. The radiation field is sufficiently strong to
overcome the collisional coupling between grains and gas at a "rip-point",
where the ratio of radiation pressure to gas pressure exceeds a critical value
of roughly 1000. When the rip point occurs outside the hydrodynamic bow shock,
a separate dust wave may form, decoupled from the gas shell, which can either
be drag-confined or inertia-confined, depending on the stream density and
relative velocity. In the drag-confined case, there is a minimum stream
velocity of roughly 60 km/s that allows a steady-state stagnant drift solution
for the dust wave apex. For lower relative velocities, the dust dynamics close
to the axis exhibit a limit cycle behavior (rip and snap back) between two
different radii. Strong coupling of charged grains to the plasma's magnetic
field can modify these effects, but for a quasi-parallel field orientation the
results are qualitatively similar to the non-magnetic case. For a
quasi-perpendicular field, on the other hand, the formation of a decoupled dust
wave is strongly suppressed.
