[FLASH-USERS] Cooling module and shocks

[Mordecai-Mark Mac Low]

You have very high densities in your circumstellar medium, which might produce extremely short cooling times because of that quadratic density dependence.  Compare your cooling time (E/Edot) to your dynamical time.  I strongly suspect your SNR is already in the momentum-driven snowplow phase, the hot interior having cooled extremely quickly.

- Mordecai

On Jul 31, 2017, at 14:23, Michiel Bustraan <michiel.bustraan at astro.su.se<mailto:michiel.bustraan at astro.su.se>> wrote:

Dear FLASH Users,

I've been using the cooling module in my supernova simulations, and have been seeing some unusual results.

My simulations involve a shock moving radially outward into a circumstellar medium.
My runs without cooling have good results, with the structure of the shock matching those in the literature.
The attached plots are the density, temperature, and radial velocity from a run without cooling.

I've been looking into the cooling module and implementing a fairly simple cooling function.
While the cooling seems to be exactly as I would expect (I plot the variable solnData(COOL_VAR,i,j,k) = abs(dedt) against my cooling function),
the impact the cooling has on the shock doesn't seem right.
The cooling causes an extreme narrowing of the shell between the forward and reverse shock, while the reverse shock almost disappears into the shell.

I wanted to ask if anyone else encountered something like this using the cooling module.

Also, just for assurance, I wanted to check what the cooling module actually calculates.
Am I correct that the variable dedt, defined by the cooling function in cool_deriv, in the Cool.F90 file, should be the cooling rate (Lambda [erg cm^3 s^-1]) multiplied by the number density squared?
And the variable EINT_VAR is the internal energy per mass [erg g^-1]? Meaning it has to be multiplied by mass density to be the energy density.
​
I know the question is a bit vague, but any advice would be appreciated.

Thank you,
Michiel Bustraan
<density_1d_20.png><temp_1d_20.png><velx_1d_20.png>

--
Mordecai-Mark Mac Low  Curator & Professor
+1-212-496-3443          Department of Astrophysics
+1-212-769-5007 (fax)    American Museum of Natural History
mmaclow (Skype, Hangout)     79th St at CPW, NY, NY, 10024-5192, USA




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