[mesa-users] Diffusion coefficient

[Masanobu Kunitomo]

Dear Pablo,

Thanks for the prompt comments. 
> If you only have convection I can imagine not much happens unless you use a much stronger reduction, as convection is extremely fast.
> 

I am sorry for the insufficient explanation. I am focusing on fully-convective stars and I want to change the diffusion coefficient in the convective region which is determined by mlt as D = conv_vel*Lambda/3.


I know the mix_factor can handle the artificially decreased diffusion, but I found that in the output files “profile##.data”, "log_D_mix" or “log_mlt_D_mix” do not change even if mix_factor is decreased by a factor of 1d6.
Thus, I would like to know (1) how to change the diffusion coefficient in the mlt subroutine (in mlt.f). If it is not possible, I would like to know (2) how the mix_factor works.

Cheers,
Masanobu



> On Jun 18, 2015, at 23:33, Pablo Marchant <pamarca at gmail.com> wrote:
> 
> You should just set mix_factor = 1d-2 in your inlist. If you only have convection I can imagine not much happens unless you use a much stronger reduction, as convection is extremely fast.
> 
> Am 18.06.2015 4:28 nachm. schrieb "Masanobu Kunitomo" <kunitomo.masanobu at c.mbox.nagoya-u.ac.jp <mailto:kunitomo.masanobu at c.mbox.nagoya-u.ac.jp>>:
> Dear all,
> 
> I am trying a test with the artificially decreased diffusion coefficient. Although I know it is possible with the “mix_factor” in controls, I did not understand how this works.
> 
> Instead of “mix_factor”, I tried a test with the modified “mlt.f” in the directory mesa/mlt/private. In the case of 100 times decreased diffusion coefficient, I multiplied a factor of 1d-2 as below:
> 	D = conv_vel*Lambda/3  *1d-2
> However, the calculated evolution was not changed.
> 
> Thus, today I would like to ask (1) whether it is possible to artificially change the diffusion coefficient in the file “mlt.f" or not and (2) how “mix_factor” works.
> 
> I am using version 6596 and I attached my mlt.f. Rotation has not been considered in our calculation. Thanks in advance for your any help!
> 
> Sincerely,
> Masanobu Kunitomo
> 
> --
> Masanobu Kunitomo, Ph.D.
> Laboratory for Theoretical Astronomy & Astrophysics (TA-Lab)
> Department of Physics, Nagoya University
> Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan 464-8602
> Email: kunitomo.masanobu at c.mbox.nagoya-u.ac.jp <mailto:kunitomo.masanobu at c.mbox.nagoya-u.ac.jp>
> 
> 
> 
> 
> 
> 
> 
> ------------------------------------------------------------------------------
> 
> _______________________________________________
> mesa-users mailing list
> mesa-users at lists.sourceforge.net <mailto:mesa-users at lists.sourceforge.net>
> https://lists.sourceforge.net/lists/listinfo/mesa-users <https://lists.sourceforge.net/lists/listinfo/mesa-users>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.mesastar.org/pipermail/mesa-users/attachments/20150619/82c38bb9/attachment.html>