[Mesa-users] AGB convergence issue

[Champagne, Arthur E]

Hi Frank,
     Thank you for your help with this. I plan to get back to it today and you’ve already finished the first thing that I was going to try. This is very encouraging!
     Thanks again,
     Art
_________________________________________________________________

Yeah, he filled his head with notions, seemingly (George Harrison)
_________________________________________________________________
A.E. Champagne
Class of 1989 William C. Friday Professor of Physics
Dept. of Physics and Astronomy, Univ. of North Carolina
Office: Phillips 230, (919) 962-7205
and Director, Triangle Universities Nuclear Laboratory, Duke Univ.
Office: TUNL 414, (919) 660-2607
aec at tunl.duke.edu<mailto:aec at tunl.duke.edu> or artc at physics.unc.edu<mailto:artc at physics.unc.edu>
_________________________________________________________________





On Mar 5, 2018, at 9:14 AM, Francis Timmes <fxt44 at mac.com<mailto:fxt44 at mac.com>> wrote:

hi art,

i changed the initial mass to 5 msun and the metallicity of z=1e-4
in the inlists i sent. it ran without issue to the specified stopping condition
of envelope_mass_limit < 1e-2 msun. screen shot attached of the final model.

these inlists are modified versions of the ones used in fields et al 2015
which you can grab from http://mesastar.org<http://mesastar.org/> in the inlist section.

fxt





On Mar 2, 2018, at 9:34 AM, Francis Timmes <fxt44 at mac.com<mailto:fxt44 at mac.com>> wrote:

hi art,

for a research project i happen to be looking at ~3 msun zams models
evolved from the pre-ms to a hot co wd with r10108.

attached are a snapshot of my current exploratory research-grade inlists
(i.e, lots of things activated, commented out, … etc as i explore sensitivities).
see if they work for you when the initial mass is changed to 5 msun.

fxt





On Mar 2, 2018, at 8:46 AM, Champagne, Arthur E <artc at physics.unc.edu<mailto:artc at physics.unc.edu>> wrote:

Hi all,
    I’m fairly new to MESA - I’m running r10108 and various test models run fine. I’ve constructed a 5 M_sun, Z=1e-4 model, which evolves in a reasonable way to the start of the AGB. The first 2 pulses look good, but it bogs down on the 3rd pulse, which occurs after the He shall narrows. The problem is “hydro_newton_step failed to accept” and debugging indicates that the problem is occurring in the zones that include the edges of the He shell. No surprise. I’ve tried various approaches to improving resolution and convergence, without success. These have come from the inlists on the web page as well as the agb and 13C pocket models in the test suite. The most recent attempt included (from the agb model):

mesh_dlog_pp_dlogP_extra = 0.25
mesh_dlog_cno_dlogP_extra = 0.25
mesh_dlog_3alf_dlogP_extra = 0.225
mesh_dlog_burn_c_dlogP_extra = 0.225
mesh_dlog_burn_n_dlogP_extra = 0.225
mesh_dlog_burn_o_dlogP_extra = 0.225
mesh_logX_species(1) = 'h1'
mesh_logX_min_for_extra(1) = -6
mesh_dlogX_dlogP_extra(1) = 0.25
mesh_logX_species(1) = 'he4'
mesh_logX_min_for_extra(1) = -6
mesh_dlogX_dlogP_extra(1) = 0.25
xtra_coef_os_above_nonburn = 0.5
xtra_coef_os_below_nonburn = 0.25
xtra_coef_os_above_burn_h = 0.25
xtra_coef_os_below_burn_h = 0.15
xtra_coef_os_above_burn_he = 0.25
xtra_coef_os_below_burn_he = 0.25
xtra_coef_os_above_burn_z = 0.25
xtra_coef_os_below_burn_z = 0.25

xtra_dist_os_above_nonburn = 0.1
xtra_dist_os_below_nonburn = 0.2
xtra_dist_os_above_burn_h = 0.2
xtra_dist_os_below_burn_h = 0.2
xtra_dist_os_above_burn_he = 0.2
xtra_dist_os_below_burn_he = 0.2
xtra_dist_os_above_burn_z = 0.2
xtra_dist_os_below_burn_z = 0.2

   I have tried playing with the parameters some, but I don’t have a good intuition yet for what they’re doing. So I was wondering if someone who has encountered this problem might have some advice on how to proceed?
   Many thanks,
   Art Champagne


_________________________________________________________________

Yeah, he filled his head with notions, seemingly (George Harrison)
_________________________________________________________________
A.E. Champagne
Class of 1989 William C. Friday Professor of Physics
Dept. of Physics and Astronomy, Univ. of North Carolina
Office: Phillips 230, (919) 962-7205
and Director, Triangle Universities Nuclear Laboratory, Duke Univ.
Office: TUNL 414, (919) 660-2607
aec at tunl.duke.edu<mailto:aec at tunl.duke.edu> or artc at physics.unc.edu<mailto:artc at physics.unc.edu>
_________________________________________________________________


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