Abstract Details
Non-Equilibrium, Non-LTE, Radiative Cooling in the 3-D MHD Code AstroBEAR
Author: Jacob N. Palmer
Requested Type: Poster Only
Submitted: 2009-04-20 16:57:33
Co-authors: Robert Carver, Adam Frank, Patrick Hartigan
Contact Info:
Rice University
6100 Main St.
Houston, Texas 77005-1
U.S.A.
Abstract Text:
AstroBEAR is a 3-D MHD code designed to model various astrophysical situations and laboratory experiments. In the astrophysical situations, handling radiative cooling is particularly crucial because emission lines from cooling produce the light seen in astronomical images, and because cooling strongly affects the amount by which the density increases in the postshock cooling zones. “Radiative” here refers to the systems cooling by emitting line radiation; they are non-radiative in the sense that radiation is a negligible component of the energy density of the flow.
We report the results of testing various means to include non-LTE cooling in shock waves into AstroBEAR. Physical processes include collisional ionization, recombination, collisional excitation, collisional deexcitation, and radiative decay for H, He, and the seven most abundant line-cooling metals. We determined how well AstroBEAR performed by comparing its postshock densities, temperatures, and ionization fractions from a planar shock simulation with those of a well-tested 1-D code that includes all the atomic physics. The match to H and He plasmas for a 40 km/s shock is excellent, and work on the metal cooling is ongoing. Applications include models of shock waves in H II regions, planetary nebulae, and stellar jets.
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