mesa-users] Semiconvection, thermohaline mixing

[Bill Paxton]

Hi Alfred,

On Oct 30, 2010, at 12:19 PM, alfred at gautschy.ch wrote:

> Whom it might concern, or who might help
> 
> Going through the whole star_defaults.dek file trying to figure out  
> where I can modify parameters, I realized that apparently MESA treats  
> semiconvection and thermohaline mixing; this is great! However, as  
> these mechanisms have various recipes on how to treat them I expected  
> that at some point in star_defaults.dek one or the other parameter  
> related to the treatment of semiconvection and/or thermohaline mixing  
> would show up; I could not find anything though. Is this right? Is  
> there no user interference possible for semiconvection and  
> thermohaline mixing? How to find out what approach was adopted in MESA?

Semiconvection + thermohaline mixing were in for a time but currently are not.
But they have top priority to be (re)implemented -- so I expect to have something soon.

> 
> I think what was said above applies also to some degree to diffusion  
> of species, also apparently implemented in MESA.

We have element diffusion that works fine in non-degenerate environments
(such as solar interior).    The section star_defaults.dek is up-to-date (I hope!).


> Is there a philosophy being followed in the MESA development on how  
> "hard-wired" code parts (i.e. no modifications through namelists  
> possible)  in say numerics, microphysics, macrophysics are documented  
> and/or made accessible to the common user?

I intend to make all the lower-level functionality available at the mesa/star
level via inlist controls.  So please let me know if you discover something
that I've missed.

Cheers,
Bill