[Mesa-users] Magnetic diffusivity

[Matteo Cantiello]

Hi Pedro,
Yes, an instance of magnetic diffusivity is calculated in the context of the Tayler-Spruit dynamo calculation. 
As per usual, you can find the place where this is calculated and the details with a grep 

grep 'magnetic diffusivity' $MESA_DIR/star/*/*.f90

Then you can replicate/adapt those routines in your run_star_extras.f and use it for your own calculations / add it to the profiles etc.

Cheers,

-M

> On Mar 21, 2019, at 2:06 PM, Francis Timmes via Mesa-users <mesa-users at lists.mesastar.org <mailto:mesa-users at lists.mesastar.org>> wrote:
> 
> not to my knowledge, but the electrical conductivity 
> could be calculated in your run_star_extras.
> 
> sigma_cond = n_e * e^2 / (m_e * f_c)
> 
> where n_e is the free electron number density (= ye * rho * N_A),
> e is the charge, m_e is the electron mass, and and f_c is the 
> relevant collision frequency. for example, the classic plasma 
> electron collision rate is f_{e,c} ~ 3e-6 * n_e * ln(lambda) * T^{-3/2} [1/sec],
> where lambda is the coulomb logarithm ~10.
> 
> fxt
> 
> 
> 
> 
>> On Mar 21, 2019, at 9:40 AM, Pedro Nuno David Gomes via Mesa-users <mesa-users at lists.mesastar.org <mailto:mesa-users at lists.mesastar.org>> wrote:
>> 
>> Dear MESA users,
>> 
>> Is there any module in MESA capable of calculating the magnetic diffusivity η (or the electrical conductivity)?
>> 
>> Thank you very much for your attention. Best regards,
>> 
>> Pedro
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> 
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