  The photoionization-driven evaporation of planetary atmospheres has emerged
as a potentially fundamental process for planets on short period orbits. While
1-D studies have proven the effectiveness of stellar fluxes at altering the
atmospheric mass and composition for sub-Jupiter mass planets, there remains
much that is uncertain with regard to the larger-scale, multidimensional nature
of such "planetary wind" flows. In this paper we use a new
radiation-hydrodynamic platform to simulate atmospheric evaporative flows.
Using the AstroBEAR AMR multiphysics code in a co-rotating frame centered on
the planet, we model the transfer of ionizing photons into the atmosphere, the
subsequent launch of the wind and the wind's large scale evolution subject to
tidal and non-inertial forces. We run simulations for planets of 0.263 and 0.07
Jupiter masses and stellar fluxes of $2 \times 10^{13}$ and $2 \times 10^{14}$
photons/cm^2/s. Our results reveal new, potentially observable planetary wind
flow patterns, including the development, in some cases, of an extended neutral
tail lagging behind the planet in its orbit.
