[mesa-users] Diffusion Updates for Degeneracy

[Evan B. <eb...@ph...>]

Hello MESA Users!

I have recently put together some notes on updates to diffusion that are available in recent MESA versions. The updated option presented here has been around in public releases since 8118, but I’ve only recently gotten around to thoroughly documenting. More development in this area is forthcoming, so stay tuned for future announcements. This material will also be explored further in a future MESA instrument paper, but I wanted to make sure that at least this level of documentation is available now since the control is currently present in the code.

For those who care about the physical motivation and justification for what’s done here, the attached pdf should have plenty of detail. For those who just want to know what controls to use when studying diffusion, here’s a quick summary of what you should do:

If studying diffusion in white dwarfs, enable the following option in the &controls section of your inlist
diffusion_use_cgs_solver = .true.

If studying diffusion in non-degenerate material, leave that option at its default value of
diffusion_use_cgs_solver = .false.

Cheers,
Evan