[Mesa-users] Lithium diffusion problem

[Evan Bauer]

Hi Aisha,

As long as you’re using a fairly recent version of MESA (9793 or newer), I would recommend bypassing all of those complicated class controls by replacing them with this single line:

	diffusion_use_full_net = .true.

Without that control, diffusion classes are sorted by atomic weight, and so there is no way to distinguish between the diffusion behavior of  li7 and be7 with your net.

To help you beyond that, we’ll need to see a complete inlist as Aaron suggested.

Cheers,
Evan


> On Mar 10, 2019, at 12:51 PM, Aaron Dotter via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> 
> Hi Aisha,
> 
> It would be helpful for you to tell us what MESA version you're using and to attach your inlist.
> 
> Aaron
> 
> 
> On Sun, 10 Mar 2019 at 3:12 pm WAN AISHAH WAN HARUN STUDENT <wanaiysha at siswa.um.edu.my <mailto:wanaiysha at siswa.um.edu.my>> wrote:
> Hi everyone,
> I have a problem in calculating my lithium abundance using this diffusion control.
> I used pp extras in my net reaction,so I include this in my &control list
> 
>        ! atomic diffusion
>       do_element_diffusion = .true. ! determines whether or not we do diffusion
>       diffusion_dt_limit = 7d11 ! no element diffusion if dt < this limit (in seconds)
>       diffusion_T_full_on = 1d3
>       diffusion_T_full_off = 1d3
>       
>       diffusion_calculates_ionization = .true.
> 
>        diffusion_num_classes = 11 ! number of classes of species for diffusion calculations
>       diffusion_class_representative(1) = 'h1'
>       diffusion_class_representative(2) = 'he3'
>       diffusion_class_representative(3) = 'he4'
>       diffusion_class_representative(4) = 'li7'
>        diffusion_class_representative(5) = 'be7'
>       diffusion_class_representative(6) = 'b8'
>       diffusion_class_representative(7) = 'c12'
>       diffusion_class_representative(8) = 'n14'
>       diffusion_class_representative(9) = 'o16'
>       diffusion_class_representative(10) = 'ne20'
>       diffusion_class_representative(11) = 'mg24'
>    
>       ! in ascending order.  species goes into 1st class with A_max >= species A
>       diffusion_class_A_max(1) = 2
>       diffusion_class_A_max(2) = 3
>       diffusion_class_A_max(3) = 4
>       diffusion_class_A_max(4) = 7
>       diffusion_class_A_max(5) = 7
>       diffusion_class_A_max(6) = 8
>       diffusion_class_A_max(7) = 12
>       diffusion_class_A_max(8) = 14
>       diffusion_class_A_max(9) = 16
>       diffusion_class_A_max(10) = 20
>       diffusion_class_A_max(11) = 24
>          
>       diffusion_use_isolve = .true.
>       diffusion_rtol_for_isolve = 1d-4
>       diffusion_atol_for_isolve = 1d-5
>       diffusion_maxsteps_for_isolve = 1000
>       diffusion_isolve_solver = 'ros2_solver'
>       
> I read the documentation,but I am still quite lost here on how to use the diffusion control.
> Results produced for He4 looks quite alright to me.However the lithium abundance at surface and convection zone calculated in diffusion is higher than the non-diffusion case(which is weird because li7 should be diffuse towards the center too ).Please let me know where did I do wrong here.
> Attached herewith are plotting results for he4 and li7  abundances vs age(from PMS)
> 
> 
> Thanks
> Aisha
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