Re: [mesa-users] mixing-regions and rotation

[Bill P. <pa...@ki...>]

Hi Pablo,

On May 13, 2013, at 5:10 AM, Pablo Marchant wrote:

> Hi. I was making my own Kippenhahn ploter starting from SimpleMesaKippi.py (Attached with an example output if you're interested), and from doing that I have a small comment and a question:
> 
> - In the description for "mixing_regions" in history_columns.list the values for rotational mixing and anonymous mixing are not mentioned. Wouldn't it be better just to refer to mesa/mlt/public/mlt_def as is done with "mixing_type" in profile_columns.list

good suggestion.   the current is a leftover from pre-rotational days of mesa.

here's what it says now

      !mixing_regions <integer> ! note: this includes regions where the mixing type is no_mixing.
      
         ! the <integer> is the number of regions to report
         ! there will be 2*<integer> columns for this in the log file, 2 for each region.
         ! the first column for a region gives the mixing type as defined in mlt/public/mlt_def.


> 
> - I would expect that in a rotating star most regions without other types of mixing would be regarded as regions with rotational mixing. Accordingly, I see large regions with mixing_type = 5 in the profile files, but the corresponding mix zones in history.data do not appear. I don't really understand why, as in private/report.f the subroutine get_mixing_regions should catch those zones. Why does this happen?
> 

I bet the problem is in the find_weakest_mixing_region routine in star/private/history.f
Since we can get abnormal situations with many small convection regions, we only
write the strongest ones in the history (remember that the number of history columns
is fixed, so we have to preset a max number of regions when we create the initial history file).
That routine is selecting "weak" regions on the basis of non-rotational diffusion coeff's ---
that is probably wrong.   It also has special checks for semiconvection and thermo_haline,
but not for rotation.  That's suspicious too.

Why don't you take a look --- if you find the problem let us know.
If you don't have time to do this, that's fine -- just tell me and I'll dig into it.

Cheer,
Bill