Radiation pressure driving of a dusty atmosphere
  Radiation pressure can be dynamically important in star-forming environments
such as ultra-luminous infrared and submillimeter galaxies. Whether and how
radiation drives turbulence and bulk outflows in star formation sites is still
unclear. The uncertainty in part reflects the limitations of direct numerical
schemes that are currently used to simulate radiation transfer and
radiation-gas coupling. An idealized setup in which radiation is introduced at
the base of a dusty atmosphere in a gravitational field has recently become the
standard test for radiation-hydrodynamics methods in the context of star
formation. To a series of treatments featuring the flux-limited-diffusion
approximation as well as a short-characteristics tracing and M1 closure for the
variable Eddington tensor approximation, we here add another treatment that is
based on the Implicit Monte Carlo radiation transfer scheme. Consistent with
all previous treatments, the atmosphere undergoes Rayleigh-Taylor instability
and readjusts to a near-Eddington-limited state. We detect late-time net
acceleration in which the turbulent velocity dispersion matches that reported
previously with the short-characteristics-based radiation transport closure,
the most accurate of the three preceding treatments. Our technical result
demonstrates the importance of accurate radiation transfer in simulations of
radiative feedback.
