[Mesa-users] relaxing entropy
Rob Farmer
r.j.farmer at uva.nl
Thu Sep 17 10:32:38 EDT 2020
Hi,
> the line "show_TRho_Profile_eos_regions = .true." doesn't output any
graph. I think it's because im using a cluster.
Then you just need to have pgstar to write to a file instead of showing a
window:
TRho_Profile_file_flag = .true.
>I tried relaxing the composition (which I also want to do) first, this
works for a while before it runs into the same problem as with entropy
relaxation.
You really want to have the relax_composition finished first before the
entropy relax. So you should work out how to get that working first. Again
look at plots, is the model doing some "odd" during the process? That can
guide you to what is causing the problem and thus the solution.
>the eos used in the hydrosimulation was the helmholtz eos without coulomb
corrections.
Someone who knows the WD eos's would need to help here.
Rob
On Wed, 16 Sep 2020 at 13:36, Akaash Conhye <ac01283 at surrey.ac.uk> wrote:
> Hi Rob,
>
> I've tried implementing your suggestions and here's what I've found:
>
>
> 1. the line "show_TRho_Profile_eos_regions = .true." doesn't output
> any graph. I think it's because im using a cluster.
> 2. ive attached the entropy profiles from the hydrosimulation and the
> entropy profile from a default run of wd_cool_0.6M so you can have a look.
> 3. the eos used in the hydrosimulation was the helmholtz eos without
> coulomb corrections. The temperatures within the white dwarf range from
> 10**4 to 10**8 so i tried adding the following line and removing the lines
> :set_HELM_OPAL_lgTs = .true.
> logT_all_HELM = 4d0
> logT_all_OPAL = 3d0
> but it doesnt look like it made much of a difference. Perhaps I've
> missed something or I've this incorrectly?
> 4. I tried relaxing the composition (which I also want to do) first,
> this works for a while before it runs into the same problem as with entropy
> relaxation.
> 5. I've also tried reducing the time step limit and max number of
> backups in a row but I still run into the same problems.
>
> Thanks,
>
> Akaash
> ------------------------------
> *From:* Rob Farmer <r.j.farmer at uva.nl>
> *Sent:* 08 September 2020 14:46
> *To:* Conhye, Akaash (UG - Physics) <ac01283 at surrey.ac.uk>
> *Cc:* mesa-users at lists.mesastar.org <mesa-users at lists.mesastar.org>
> *Subject:* Re: [Mesa-users] relaxing entropy
>
> Hi,
>
> Retries and backups are telling you that mesa is struggling to make the
> change requested for that step of the entropy relax process. If you look in
> a T-rho plot with
>
> show_TRho_Profile_eos_regions = .true.
>
> enabled, does it look like the model is crossing any EOS boundaries when
> it crashes?
>
> How different is your new entropy profile compared with the starting one
> for the wd? The bigger the difference the harder it will be.
>
> How "close" is the EOS in mesa (for WD's) to what was used in the hydro
> simulation? The bigger the difference the harder it will be. Remember
> MESA's eos is a composite of several sources, different parts of a star may
> be using different EOS's.
>
> > tried using the one provided in the "relax_composition_j_entropy"
> template to see what would happen.
>
> The entropy profile for relax_composition_j_entropy describes a 10 solar
> mass TAMS star so that is not going to look like a 0.6Msun WD. So i'm not
> surprised that starting from a WD and trying to turn it into a 10Msun star
> fails.
>
> Rob
>
>
>
> On Tue, 8 Sep 2020 at 13:36, Akaash Conhye via Mesa-users <
> mesa-users at lists.mesastar.org> wrote:
>
> Hi all,
>
> I've been trying to relax a white dwarf's entropy profile (obtained from
> hydrodynamic simulations). The template I used was wd_cool_0.6M. To the
> file inlist_wd_cool_0.6M I've added the following lines:
>
> relax_initial_entropy = .true.
> max_steps_to_relax_entropy = 1000
> timescale_for_relax_entropy = 1d-9 ! in years
> max_dt_for_relax_entropy = 1d-8 ! in years
> num_timescales_for_relax_entropy = 100
> relax_entropy_filename = 'entropy_unrlx.dat'
>
> Where entropy_unrlx.dat is my entropy profile. Upon running, here is the
> output on my terminal:
>
> read inlist_wd_cool_0.6M
> set_eos_PC_parameters
> mass_fraction_limit_for_PC
> 1.0000000000000000D-03
> logRho1_PC_limit
> 2.9990000000000001D+00
> logRho2_PC_limit
> 2.7999999999999998D+00
> log_Gamma_all_HELM
> 1.0000000000000000D+00
> log_Gamma_all_PC
> 1.3010299956000000D+00
> PC_Gamma_start_crystal
> 1.7400000000000000D+02
> PC_Gamma_full_crystal
> 1.7600000000000000D+02
> PC_min_Z
> 9.9900000000000000D-01
> load saved model wd_0.6.mod
>
> WARNING -- inlist initial_z ignored
> 1.0000000000000000D-02
> using saved initial_z instead
> 2.0000000000000000D-02
>
>
> relax_initial_entropy
> relax_entropy: max_steps_to_use 1000
> retry 129
> retry 129
> backup 129
> retry 129
> retry 129
> backup 129
> retry 129
> retry 129
> dt
> 7.7046264609375010D-11
> min_timestep_limit
> 1.0000000000000001D-09
>
> stopping because of problems dt < min_timestep_limit
>
> do_relax_initial_entropy ierr -1
> do_star_job_controls_after ierr -1
> before_evolve_loop ierr -1
> DATE: 2020-09-08
> TIME: 11:00:31
>
> Some things Ive tried to do to fix this problem:
>
> 1. decreasing min_timestep_limit (by setting it to a smaller value in
> the controls section of my inlist) so that i don't get the inequality
> dt<min_timestep_limit. But this doesn't solve the problem as dt continues
> to get smaller.
> 2. using a different entropy profile. Initially I'd thought that there
> was something wrong with my entropy profile, so I tried using the one
> provided in the "relax_composition_j_entropy" template to see what would
> happen. I got the same error message.
>
>
> the version of MESA im using is 12115. My operating system is Ubuntu
> 20.04.1 LTS 64 bit. Im running MESA on a cluster (eureka).
>
> Thanks,
>
> Akaash
>
>
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