[FLASH-USERS] "Negative 3T internal energy" in a strong magnetic field

Klaus Weide klaus at flash.uchicago.edu
Wed Feb 28 08:55:34 EST 2018


On Wed, 28 Feb 2018, Kazuki Matsuo wrote:
> 
> I'm working on 3T MHD simulation of laser-generated magnetized plasma.
> 
> My code works well with a 5T magnetic field in 2D cylindrical
> geometry. However,
> if I increase the magnetic field to 100 T, I got the error message
> "Negative 3T internal energy".
> 
> Do you know how to deal with such a strong magnetic field?

Have you already tried the following?

- Enforce a smaller timestep, for example by setting CFL=1.0 or by 
setting dtmax.

- Use eintSwich, perhaps with a value of 1.e-3 or 1.e-4 (requires 
use_auxEintEqn=.TRUE.)


These are rather generic suggestions, hopefully others can give more 
specific advice relevant to strong magnetic fields.

Klaus



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