[Mesa-users] Lithium diffusion problem

[Aaron Dotter]

Hi Aisha,

I suggest that you make a plot of the location of the base of the surface
convection zone in your models with and without diffusion.

Are they the same or different?  If different, does the difference help you
to understand with the Li profiles look the way they do?

Aaron

On Mon, Mar 11, 2019 at 2:08 AM WAN AISHAH WAN HARUN STUDENT <
wanaiysha at siswa.um.edu.my> wrote:

> Sorry,forgot to share details needed.
> I used mesa-r10398 version and attached herewith my inlist and graph
> lithium abundance profile with diffusion and without diffusion.
> I believe something wrong with my inlist because lithium abundance with
> diffusion is higher than without it at solar surface.(Abundance at the
> interior looks fine though)
> H1 and He4 abundances looks good too on surface and interior. Did I use
> diffusion control setting correctly for lithium?
>
> Thanks Evan Bauer..Tried the control you gave but the li7 abundance result
> still higher at the surface .
> diffusion_use_full_net = .true
>
> Cheers,
> Aisha
>
> On Mon, Mar 11, 2019 at 4:25 AM Evan Bauer <ebauer at physics.ucsb.edu>
> wrote:
>
>> 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> 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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>>> mesa-users at lists.mesastar.org
>>> https://lists.mesastar.org/mailman/listinfo/mesa-users
>>>
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