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<p class="MsoNormal">Hi FLASH users,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’ve been trying to do some 3D FLASH MHD simulations of laser ablation focusing on the Biermann battery generated magnetic field. I’ve run into issues with stability and a very small time step that make the simulations infeasible. As a
test example, I took the Laserslab example.par simulation, moved it to 3D, and added Biermann3T. Attached is the .par file that I’m using. For a CFL of .1, the simulation starts out with timesteps of about 1e-19 and crashes (negative 3T) after about a thousand
time steps. It also crashes for CFLs of .05 and .025. <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Does anyone have advice for dealing with stability issues and small time steps in 3D Biermann3T simulations? I’m hoping to be able to run my simulation for a few nanoseconds.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">For the setup command, I’ve swapped +uhd3t for +usm3t from the Laserslab setup and made the simulation 3D cartesian.
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Best,<o:p></o:p></p>
<p class="MsoNormal">Tim Johnson<o:p></o:p></p>
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