[Mesa-users] flux plot

[Frank Timmes]

hi diogo,

> ... a big thanks to the MESA devs that added the options to print rates and reaction-specific energy fluxes ...

mainly done by rob farmer and earl bellinger. recorded in section 10.3 of mesa vi.

fxt





> On Jul 10, 2024, at 1:01 AM, <diogo.capelo at tecnico.ulisboa.pt> <diogo.capelo at tecnico.ulisboa.pt> wrote:
> 
> Hi Rita,
>  
> The most recent version of MESA includes specific profile_columns.list controls to output of nuclear reactions in erg/s, which saves some work if you’re just interested in the energy flux.
>  
> As for the default way the screened  (and I believe raw rates as well, but someone will correct me if I’m mistaken) rates are printed, they are in units that depend on the number of reactants, so if you want a number flux you will have to do some conversion from mass density to molar density (Y factor) for each reactant and multiply these by the number presented for the rate, or convert from the other end the units of the rate, which will be different for reactions with a different number of reactants. 
>  
> This process is explained in detail in the net_def file, e.g. in “mesa-r23.05.1/net/public/net_def.f90”:
>  
> “The units here depend on the number of reactants. In all cases, the rate_screened times as many molar fractions as there are reactants gives a number with the same units as dy/dt. So, for a 2-body reaction, there are 2 Y-factors, each with units [moles/gram] and the rate_screened units for such a reaction are grams/(mole-sec)], which when multiplied by [moles/gram]^2 gives the same units as dy/dt. For a 1-body reaction (e.g., a decay), there is only 1 Y-factor, so the units are [1/second]. Similarly, a 3-body reaction will have rate_screened units of [gram^2/(mole^2-sec)].”
>  
> I hope this helps, and good luck!
>  
> (And as someone who uses these options extensively, a big thanks to the MESA devs that added the options to print rates and reaction-specific energy fluxes into the default output option!)
>  
> --
> Diogo Capelo
>  
> From: Mesa-users <mesa-users-bounces at lists.mesastar.org> On Behalf Of Kit Yu Lau via Mesa-users
> Sent: 10 de julho de 2024 07:48
> To: Frank Timmes <fxtimmes at gmail.com>
> Cc: mesa-users <mesa-users at lists.mesastar.org>
> Subject: Re: [Mesa-users] flux plot
>  
> Hi all,
>  
> I used the add_raw_rates in the new version r24.03.1 and it prints out the rates. I am not very sure if the number represents the cross section or the stellar reaction rate or (stellar reaction rate per volume??) in 1 body and 2 body reactions?
>  
> Thank you very much.
>  
> Regards,
> Rita
>  
>  
> On Wed, Jun 12, 2024 at 10:26 PM Frank Timmes <fxtimmes at gmail.com <mailto:fxtimmes at gmail.com>> wrote:
>> hi rita,
>> 
>> please keep mesa-users on all replies.
>> 
>> this cannot be done easily in r9795; much source code modifications and/or gyrations with a run_star_extras would be needed. maybe consider upgrading to r24.03.1.
>> 
>> fxt
>> 
>> 
>> 
>> 
>> > On Jun 12, 2024, at 7:20 AM, Kit Yu Lau <kityulau.rita at gmail.com <mailto:kityulau.rita at gmail.com>> wrote:
>> > 
>> > Hi,
>> > 
>> > I am sorry. But I am using mesa-r9795. It seems there is not add_raw_rates in this version. How to output each of the reaction rate as a function of time in this version?
>> > 
>> > Thank you very much.
>> > 
>> > Regards,
>> > Rita Lau
>> > 
>> > On Wed, Jun 12, 2024 at 9:46 PM Frank Timmes <fxtimmes at gmail.com <mailto:fxtimmes at gmail.com>> wrote:
>> > hi rita,
>> > 
>> > see section 10.3 of mesa VI (jermyn et al 2023) and then $MESA_DIR/star/defaults/history_columns.list and $MESA_DIR/star/defaults/profile_columns.list .
>> > 
>> > fxt
>> > 
>> > 
>> > 
>> > 
>> > 
>> > > On Jun 12, 2024, at 6:21 AM, Kit Yu Lau via Mesa-users <mesa-users at lists.mesastar.org <mailto:mesa-users at lists.mesastar.org>> wrote:
>> > > 
>> > > Hi everyone,
>> > > 
>> > > I would like to make a flux plot for the ns_h directory (accreting neutron stars). How can I print out the reaction rates (or cross sections) for each reaction as a function of time ? Thank you very much.
>> > > 
>> > > Regards,
>> > > Rita
>> > > 
>> > > _______________________________________________
>> > > mesa-users at lists.mesastar.org <mailto:mesa-users at lists.mesastar.org>
>> > > https://lists.mesastar.org/mailman/listinfo/mesa-users
>> > > 
>> > 
>> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.mesastar.org/pipermail/mesa-users/attachments/20240710/fb597b24/attachment.htm>