[mesa-users] wd diffusion

[Jing Luan]

Hi Robert,

Thank you very much :-) Yes, I have tried both.

1, wd_diffusion sets the surface tau = 15, when I change it to 5 (or even
lower), mesa keeps 'retry' for the first model.

2, wd_surf_at_tau_1m4 sets tau=1d-4, which is good for me, but it has the
diffusion off. When I turn on the diffusion, then mesa keeps 'retry'.

Below I attach my latest inlist, and 2 starting models which I have tried.

Since the diffusion & small surf_tau do not work together. I tried to
create a mod file '0.6M-wd-diffused.mod' by setting surf_tau=15 &
diffusion=.true. to get the H and He well separated. Then I start with with
this model by setting surf_tau=0.01, hoping that mesa could add the low tau
part onto this model, but mesa cannot converge even for the first model.

Many many thanks :-)

Sincerely,
Jing

On Mon, Jan 9, 2017 at 10:19 AM, Robert Farmer <rjfarmer at asu.edu> wrote:

> Hi
> Have you tried the wd_diffusion and/or the wd_surf_at_tau_1m4  test_suite
> cases?
>
> If you have and are still having problems, can you post your inlists with
> the changes you've made.
>
> Regards
> Rob
>
> On Sun, Jan 8, 2017 at 4:55 PM, Jing Luan <jingluan.xw at gmail.com> wrote:
>
>> Hello,
>>
>> I'd like to make a WD model with pure hydrogen atmosphere, i.e. all
>> heavier elements have settled down. Thus I turn on diffusion in mesa.
>> However, mesa has a hard time converging when I also require the surface
>> optical depth to be 5 or even lower (actually I need the low optical depth
>> part to be treated well in the model). Does anyone know that why diffusion
>> does not work well in low optical depth part please? Or how do I get a WD
>> model with hydrogen, helium and metals well separated in depth while its
>> surface goes up to tau=0.01 please?
>>
>> Many thanks!
>>
>> Sincerely,
>> Jing
>>
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>
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