Re: [mesa-users] changes in spatial and temporal resolution in MESA

[Robert F. <rjf...@as...>]

Hi

>'mesh_delta_coeff' in all of the 5 inlists provided i.e.
inlist_remove_core, inlist_adjust, inlist_edep, inlist_explosion

first you need to understand how mesa is doing the ccsn in 7624. I would
start from the ccsn test case and not the mesaIII inlists

In the ccsn test case there are several inlists corresponds to a single
step in the process of exploding a star, looking in the rn file to find the
order they are ran in you'll see:

do_one inlist_adjust_header ready_to_remove_center.mod
do_one inlist_remove_core_header ready_to_shock.mod
do_one inlist_edep_header done_with_edep.mod
do_one inlist_explosion_header final.mod

I would thus suggest you only worry about making changes to the last set of
inlists inlist_explosion and inlist_explosion_header as that is what is
doing the explosion, the other inlists setup the explosion by removing the
core and inserting the extra energy.

> mesh_delta_coeff_for_highT vs mesh_delta_coeff

You can change the value of mesh_delta_coeff between "normal" temperatures
and high temperatures, usually you want to reduce the number of zones at
high T to cut the computational time.

I suggest a good read of the
http://mesa.sourceforge.net/docs/r7624/controls_defaults.html#mesh_adjustment
section to see where the split between normal and high T occurs.

>In order to change the spatial resolution, is it only the
'varcontrol_target'

No, varcontrol_target controls the timestep not the spatial resolution,
look over
http://mesa.sourceforge.net/docs/r7624/controls_defaults.html#timestep_controls
for the various options.

mesh_delta and varcontrol are the easiest ways to change the mesh/timestep
but they are not the only ways, they are also somewhat crude and apply
everywhere there are other controls than can add mesh/time points only
where you want it to go.

>I'm not sure what's the role of 'min_timestep_limit' here?

Its the minimum timestep in seconds mesa will take, if it tries to take a
smaller timestep mesa will stop.

Rob



On Tue, Mar 28, 2017 at 8:56 AM, Subedi, Shiv Kumar <ss3...@oh...>
wrote:

> Dear All!
>
>
> Currently I have been using MESA version 7624 to study the explosive
> nucleosynthesis phenomenon in Core-Collapse Supenova (CCSN). For this I
> have been using the explosive nucleosynthesis inlists provided in the MESA
> III Instrument Paper Inlists. I now wish to do the convergence tests
> changing the spatial resolution and temporal resolution in the inlists.
>
>
> I have an idea that in order to investigae the changes in spatial
> resolution, we need to make changes in the values of the 'mesh_delta_coeff'
> in all of the 5 inlists provided i.e. inlist_remove_core, inlist_adjust,
> inlist_edep, inlist_explosion and inlist_massive_defaults. But when I go
> into individual inlists I find following statements of the 'mesh_delta
> coeff' and I'm not sure which of them should I change? I am also curious to
> know about the choice of the values of the mesh_delta_coeff values below.
>
>
> Inlist_adjust:
>
>                       mesh_delta_coeff_for_highT = 1.4
>
>
> Inlist_remove_core:
>
>                       mesh_delta_coeff_for_highT = 1.4
>
>
> Inlist_explosion:
>
>                         mesh_delta_coeff = 0.8
>
>
> Inlist_massive_defaults:
>
>                         mesh_delta_coeff = 1.5
>                        mesh_delta_coeff_for_highT = 2.5
>                        logT_max_for_standard_mesh_delta_coeff = 9.0
>                         logT_min_for_highT_mesh_delta_coeff = 9.5
>
> In addition, In order to change the spatial resolution, is it only the
> 'varcontrol_target' that we need to change? I am confused when I look into
> the inlist_explosion of MESA Summer School 2015 Minilab 2 (simulating
> supernova explosions and nucleosynthesis) exercise where it provides
> following set of timestep controls varriables.
>
> varcontrol_target = 1d-3
> min_timestep_limit = 1d-10
>
> I'm not sure what's the role of 'min_timestep_limit' here?
>
> Also, in order to make the supernova explosion to work, I had to make
> following change in the 'solver controls' section in  'inlist_explosion' of
> the MESA III Instrument Paper Inlists.
> I replaced 'use_time_centering = .true. '  by 'use_energy_coversion_form=.
> true.'.
> I am not sure what are the roles of each of above parameters and if its
> the right way to undergo the supernova explosion in MESA?
>
> I'd really appreciate if anyone could provide his/her useful suggestions
> and guidance.
>
> Sincerely,
> Shiv Subedi
> Graduate Student
> Ohio University
> Athens, Ohio
>
>
>
>
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