[mesa-users] mesa release: version 7499

[Bill Paxton]

Happy Vernal Equinox!

here's a new mesa release to celebrate the occasion.

Cheers,
Bill





change default kap lowT blend region to logT 3.88 to 3.80 from 4.1 to 4.0 in order to avoid putting H ionization in blend region
	
use Lrad/Ledd instead of L/Ledd for gamma factor in calculation of omega_crit (suggested by Matteo)

put gravitation G in GLOB(15) for FGONG files (suggested by Joergen Christensen-Dalsgaard)

add Z=0.02 He ZAMS -- can access like H ZAMS; interpolates masses using prebuilt models from 3.25M to 18.25M
	to use, change 'zams_filename' in &star_controls from 'zams_z2m2_y28.data' to 'zams_z2m2_y98.data'

add grid control for semiconvection -- e.g., xtra_coef_scz_above_heb_cz
         !### xtra_coef_scz_above_{nonburn | hburn | heburn | zburn}_cz
         ! Make these < 1 to increase resolution in semiconvective region adjacent to convective region.
         ! e.g., 'xtra_coef_scz_above_nb_cz' is extra coef for semiconvectize zone above a non-burn convective zone.

add overshoot_alpha (suggested by Sebastien Deheuvels)
               ! The value of Hp for overshooting is limited to the radial thickness
               ! of the convection zone divided by overshoot_alpha.
               ! only used when > 0.  if <= 0, then use mixing_length_alpha instead.

change overshoot controls to specify shell or core (suggested by Jieun Choi)
            !### overshoot_f_above_nonburn_core
            !### overshoot_f0_above_nonburn_core
            !### overshoot_f_above_nonburn_shell
            !### overshoot_f0_above_nonburn_shell
            !### overshoot_f_below_nonburn_shell
            !### overshoot_f0_below_nonburn_shell

fix overshoot code to handle cases where f0*Hp is so small that r0 is in same cell with r_edge

now require user to set f0 > 0 for overshooting whenever have f > 0; both step and exponential

            ! Parameters for exponential diffusive overshoot are described in the paper by Falk Herwig,
            ! "The evolution of AGB stars with convective overshoot", A&A, 360, 952-968 (2000).

            ! NOTE: In addition to giving these 'f' parameters non-zero values, you should also
            ! check the settings for `mass_for_overshoot_full_on` and `mass_for_overshoot_full_off`.

            ! The switch from convective mixing to overshooting happens
            ! at a distance f0*Hp into the convection zone
            ! from the estimated location where `grad_ad == grad_rad`, 
            ! where Hp is the pressure scale height at that location.
            ! A value <= 0 for f0 is a mistake -- you are required to set f0 as well as f.
            ! take a look at the following from an email concerning this:
            
               ! Overshooting works by taking the diffusion mixing coefficient at the edge 
               ! of the convection zone and extending it beyond the zone. But -- and here's the issue -- 
               ! at the exact edge of the zone the mixing coefficient goes to 0.  So we don't want that.
               ! Instead we want the value of the mixing coeff NEAR the edge, but not AT the edge.  
               ! The "f0" parameter determines the exact meaning of "near" for this.  It tells the code 
               ! how far back into the zone to go in terms of scale height. The overshooting actually 
               ! begins at the location determined by f0 back into the convection zone rather than at 
               ! the edge where the diffusion coeff is ill-defined.  So, for example, if you want 
               ! overshooting of 0.2 scale heights beyond the normal edge, you might want to back up 
               ! 0.05 scale heights to get the diffusion coeff from near the edge and then go out 
               ! by 0.25 scale heights from there to reach 0.2 Hp beyond the old boundary.  In the 
               ! inlist this would mean setting the "f0" to 0.05 and the "f" to 0.25.
            
            ! There is no default value for f0; if you set f > 0 then you must get f0 > 0 as well.

            ! step_overshoot:

            ! As above, `f0*Hp` determines r0 where switch from convection to overshooting.
            ! Overshooting extends a distance `step_f*Hp0` from r0
            ! with constant diffusion coeff `D = step_D + step_D0_coeff*D0`
            ! where D0 = diffusion coefficient D at point r0.


from Pablo: a few incremental changes to binary

small changes in donor switch
include "Arras" scheme for mass transfer
add "other" routine and extra options for mdot_edd
add option to limit implicit mass transfer rate


from Josiah: a host of changes related to weak reactions


Add Coulomb_Info structure

In order to calculate coulomb corrections for the weak reactions, the
rates module will need to know the conditions (density, temperature,
etc) at which the reaction is occurring.

This creates a structure similar to the Screen_Info structure, which
will allow one to pass this information down as needed.
------------------------------------------------------------------------

Pass Coulomb_Info through weak rates calls

When the routines that evaluate the weak reactions are called, they need
to pass down a filled Coulomb_Info structure.  This changes the call
signatures of the functions to allow this information to be passed down.

Right now, it is only fed into the ecapture routines.  But if future
users want to evaluate coulomb corrections on the fly for the regular
weaklib reactions, it will be straightforward.

This refactors the existing routine that calculated the coulomb
corrections to use the new Coulomb_Info structure.  It also paves the
way for multiple implementations of the corrections.
------------------------------------------------------------------------

Set context before evaluating weak reactions

The Coulomb_Info structure needs to be populated before evaluating the
weak reactions.  The net module now calls coulomb_set_context before
calling eval_weak_reaction_info.

This also adjusts the call signature of all of the calls to
eval_weak_reaction_info in the net module to include the Coulomb_Info
structure.

In the case of eval1_weak_rate and do_eval_nse_eps_info, the
Coulomb_Info structure is passed, but left un-populated, since it will
remain unused deeper down.  This is because the reactions that will be
evaluated (e.g., eval_ni56_ec_rate) aren't calculated using the ecapture
module.
------------------------------------------------------------------------

Add electron screening corrections

The electron density at the nuclear is modified from the background
density due to screening.  This implements two approaches to quantifying
the chemical potential shift due to this affect.
------------------------------------------------------------------------

Add corrections used by Juodagalvis

This adds an option to use the same expression for the ion chemical
potential as used by Juodagalvis et al. (2010).
------------------------------------------------------------------------

Add new option for ion chemical potential

This adds the ability to use the Potekin, Chabrier and Rogers (2009) ion
chemical potential to do dense plasma corrections to the weak rates.

This also refactors the computation of a few commonly used quantities
into the Coulomb_Info data structure.
------------------------------------------------------------------------

Update A=20,24 weak rates

Use the log-(ft) values from Martinez-Pinedo et al. (2014), but
excluding the forbidden transition.
------------------------------------------------------------------------

Allow control of ecapture reactions from star_job

For users interested in using these rates, add

    use_special_weak_rates = .true.
    ion_coulomb_corrections = 'PCR2009'
    electron_coulomb_corrections = 'Itoh2002'

to your star_job inlist.
------------------------------------------------------------------------

Rewrite special weak reaction tests

The tests that exercise the weak reactions activiated by
use_special_weak_rates and related routines were rewritten to be simpler
and quicker.






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