Update 6/3

  • Read ​Tremblin and Chiang for computational charge exchange. The paper is a followup to earlier studies of charge exchange between planetary and stellar winds, which used Monte Carlo simulations of particles. Here they use the hydrodynamic equations (no magnetism, Coriolis and centrifugal forces, or tidal gravity); the isothermal planetary wind was initialized as 80% ionized, following Murray-Clay et al. The planetary wind incorporated photoionization/recombination and advection. To incorporate charge exchange, the hydrodynamic code was augmented with chemical reaction solvers, where beta is the reaction rate.

These equations take reverse exchange into account, so as not to overestimate neutral hydrogen (still slightly overestimated). They are very similar, but not identical to, the equations used by ​Christie et al.

The simulations appear to reproduce the observed absorption curves well, with asymmetry between the two sides of the Doppler shift.

  • Used Jonathan's Matlab code to examine change of bow shock radius with magnetic fields. If sigma* and sigmap are equal, the bow shock radius is unchanged with or without magnetic field - ratio of radius to orbital separation, chibow = 0.240468. With sigma* = 1, sigmap = 0.1, chibow = 0.148204; sigma* = 0.5, sigmap = 0.1, chibow = 0.187300; sigma* = 0.1, sigmap = 0.5, chibow = 0.302483; sigma* = 0.1, sigmap = 1, chibow = 0.363674; and with sigma* = 0.5 and sigmap = 1, chibow = 0.297793 ≈ chiCoriolis.
  • Also attempted to recreate isotropic planetary wind with no rotation (Run5 from planet directory). Copied .data files, but clearly didn't turn out correctly. Need to figure out why.

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