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Update 6/23

Ran planetary simulations with no rotation and an anisotropic temperature profile with various parameters. See my page for density movies. Changing lambda performs as expected - with lambda = 5, there is a marked increase in the strength of the wind, and with lambda = 15 there is very little to no wind. Changing the mass of the planet didn't result in quite a clear changes, but overall it doesn't appear to have affected the wind very much. Hotter planet appears to have a stronger outflow, while the cooler planet doesn't differ qualitatively from the original run. The last simulations I've performed so far were decreasing the ambient temperature, and this doesn't appear to affect the wind very much in terms of density. Momentum plots, however, appear to show outflows that are stronger by a factor of two.

Also researched justification for using a fluid approximation for charge exchange. In Christie et al., they calculate the mean free path (sound speed over rate of reaction) for charge exchange and note that it is less than the planetary radius (in regions dominated by the planetary wind) to justify using the fluid approximation, with mixing and exchange primarily at turbulent boundaries. In Murray-Clay et al., they justify the fluid approximation in general by comparing the scale height H to the mean free path of a particle, with the fluid approximation holding for H > lambda_mfp at the sonic point (in other words, the exobase [where H = lambda_mfp] is above the sonic point). Thus, H > R_p as well, and therefore greater than mfp of charge exchange near the planet.

Finally, working my way through Zel'dovich and Raizer for hydrodynamics. Beginning viscosity and heat conduction at the moment.