[FLASH-USERS] combining MHD and thermal conduction

[ERNESTO ZURBRIGGEN]

Hi Jon!

>It made me wonder if there is some numerical way that the implementations
of thermal conduction and MHD interfere with each other.

I have used MHD+(isotropic) Conduction without any problem of that sort.
One confusing thing is that you can select Diffusion/split and
Diffuse/unsplit. Be careful with that.

Something curious is that if the simulation include unsplit/MHD +
(regardless of split or unsplit) Diffusion you have to also set the runtime
parameter addThermalFlux=.false. (.true. by default)
Otherwise, you are including the thermal conduction effect twice, i.e.,
heat diffusion via the HYPRE libraries decoupling the heat equation, and
adding the thermal flux to the total energy flux in the Hydro unit.
I think the most consistent configuration would be unsplit/MHD + Diffusion/
unsplit + addThermalFlux=.false.


>I tried reducing the conductivity further and found that only by reducing
it by many orders of magnitude (~8) was I able to get runs that didn't
crash

Maybe you can try reducing the parameter dt_diff_factor.

Are you using super-time-stepping?

Best!
Ernesto.
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