Radiative Instability

Problem Background

This is a study of the oscillatory instabilities in radiative shocks. Radiatively cooled shocks in a stationary frame will sometimes exhibit oscillatory behavior as the sharp velocity gradient produces pressure imbalances that expand and contract. For more information, the references below detail the problem:

Main references:
[1] Numerical Analysis of the Dynamic Stability of Radiative Shocks, Strickland, R. & Blondin, J.M. 1995, ApJ, 449, 727 ​link.
[2] A Numerical Study of the Stability of Radiative Shocks, Imamura, J. N.; Wolff, M. T.; Durisen, R. H. 1984, ApJ, 273, 667 ​link.

Reason for Test

This is a 1D test to verify that analytic cooling is working correctly. There are 3 tests which each have a different cooling coefficient and power law exponent (beta).

Results

The new chombo can be verified by comparing it to the density in the reference chombo. The shocked gas has hit the wall and started to oscillate.

Beta	Reference Chombo	New Chombo
0.0	TestRef(RadiativeInstability0, 600px)	TestSim(RadiativeInstability0, 600px)
0.5	TestRef(RadiativeInstability05, 600px)	TestSim(RadiativeInstability05, 600px)
1.0	TestRef(RadiativeInstability1, 600px)	TestSim(RadiativeInstability1, 600px)

TestLog(RadiativeInstability0) TestLog(RadiativeInstability05) TestLog(RadiativeInstability1)