[Mesa-users] Convergence problems using other_D_mix with mesa-r15140

[Francis Timmes]

as an experiment, try setting 

     use_gold2_tolerances = .false.

fxt



> On Mar 24, 2021, at 12:51 PM, Arman Aryaeipour via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> 
> Hi Rob,
> 
> Thank you for your quick response! I started by first loading in a 1 Msun white dwarf (regenerated with mesa-r15140) and accreting solar material atop it until the maximum temperature reached 10^8 K. At this point the run was stopped and saved as a model. I then started another run with this saved model and started the mixing.
> 
> So, the terminal_output.txt file I've attached is MESAs output from the beginning of the mixing. Before that the accretion phase was also run with mesa-r15140 too.
> 
> Many thanks,
> Arman 
> From: Rob Farmer <r.j.farmer at uva.nl>
> Sent: 24 March 2021 19:34
> To: Aryaeipour, Arman (PG/R - Physics) <a.aryaeipour at surrey.ac.uk>
> Cc: mesa-users at lists.mesastar.org <mesa-users at lists.mesastar.org>
> Subject: Re: [Mesa-users] Convergence problems using other_D_mix with mesa-r15140
>  
> Hi,
> 
> Your models are having problems right from the first step. Have you regenerated your starting model with the  new mesa version or are you starting with a model made with 10108?
> 
> Rob
> 
> On Wed, 24 Mar 2021 at 20:29, Arman Aryaeipour via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> Dear Mesa-users,
> 
> I've recently migrated over to mesa-r15140 from mesa-r10108 for modelling nova outbursts. 
> In these models, I use the other_D_mix hook routine to implement some mixing between the white dwarf and its envelope when the maximum temperature reaches 10^8 K. This mixing is initially only around the white dwarf and envelope interface, and slowly extends out further into the white dwarf and envelope over the course of a few hundred seconds.
> 
> When this mixing was carried out using mesa-r10108, the model had no problem converging and evolved through the mixing phase I implemented. However, with mesa-r15140 the model quickly runs into convergence issues after mixing begins and the timestep goes to zero. I've attached the terminal_output.txt file which contains MESAs output from when I start mixing, with report_solver_progress turned on. I've also provided my inlist. 
> 
> I would be grateful if someone could explain to me what changes in the new version of MESA cause the convergence problems once I begin mixing, and if there is a way I can change these settings to revert them back to how they were in mesa-r10108.
> 
> Many thanks in advance!
> 
> All the best,
> Arman Aryaeipour 
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