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Update 10/7
AAS
Current version of the abstract:
The photoionization-driven evaporation of planetary atmospheres has emerged as a potentially fundamental process for planets on short period orbits. Using AstroBEAR, an AMR multiphysics code, in a co-rotating frame centered on the planet, we model in three dimensions 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 2x1013 and 2x1014 photons/cm2/s. These simulations 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. In addition, the role of radiation pressure in shaping exoplanet photoevaporation remains a topic of contention. Radiation pressure from the exoplanet's host star has been proposed as a mechanism to drive the escaping atmosphere into a "cometary" tail and explain the high velocities observed in systems where mass loss is occurring. Using simulations of a planet modeled after HD 209458b and subject to both ionizing and Lyman-α radiation, we demonstrate that for the Lyman-α flux expected for HD 209458, radiation pressure is unlikely to significantly affect photoevaporative winds or to explain the high velocities at which wind material is observed. Charge exchange between the stellar and planetary winds has also been suggested as a method for creating the observed Lyman-α absorption signature. We present results of simulations that explore the effect of charge exchange on our synthetic observations. In addition, we present simulations of the effect of stellar and planetary magnetic fields on our self-consistently launched wind.
MHD
Pressure protections around the planet. Some very small B fields in the planet - may need to fix the field to zero inside the planet at every step?
Also realized that I set the field to zero inside Rp only, not inside Rob. That may help some. Perhaps it's even worth fixing the field to zero out to within a small but significant distance from Rob?
Also plan to try fixed-boundary global sim when I get a chance.
Charge Exchange
Still running fairly slowly. I expect it should reach steady state soon, though (assuming we don't enter a cycle with the stellar wind - I am using John's intermediate case).
The wind is turning inward as it approaches the outside boundary - I think this is expected due to Coriolis/centrifugal force/differential rotation? But haven't really had time to investigate yet.
AMR profiling
Actual profiling should finally run successfully on Stampede. Also on my to-do list is to make sure we're not waiting longer than necessary for local/MPI rays.
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