[FLASH-USERS] MHD simulation of plasma focus machine

[Hansen, Eddie]

Hi Christos,

It’s difficult to determine why this is happening without more information of what you’re trying to simulate. The ZPinch example problem uses several settings and units specific to Z-pinches, but it appears that you are not simulating a Z-pinch. For example, it includes a current drive with B-field diffusing in from the upper-r boundary condition, and a ‘vacuum’ region with very high constant resistivity.

I would need to know more about the modifications you made to the Simulation_* files, par file, Config, setup command, etc.

--
Eddie Hansen
Research Scientist
Flash Center for Computational Science


From: flash-users <flash-users-bounces at flash.rochester.edu> on behalf of ddk172 at edu.hmu.gr <ddk172 at edu.hmu.gr>
Date: Friday, July 7, 2023 at 5:04 AM
To: flash-users at flash.rochester.edu <flash-users at flash.rochester.edu>
Subject: [FLASH-USERS] MHD simulation of plasma focus machine
Hello everyone!
I am trying to model a plasma focus machine using 2D flash, using a
modified version of Z-Pinch example of FLASH4.7 version. Currently, i am
running some simulations using Deuterium equation of state
DD-006-imx.cn4 for plasma and vacuum. The density is very low (1.2e-6
gr/cm^3) and i assume is comparable to the vacuum density of MHD
simulations. I have assumed a magnetic field deduced from the current i
measured at the experiment, the initial conditions can be seen on
attached figure. Early on the simulation( ~20ns) a problem arise that
looks like numerical instability that is not familiar to me, as seen at
the attached figure of density. This problem appears when magnetic
resistivity flag is set true. Is anyone familiar with this kind of
problem? If so, ask me for any additional information you need.

Thanks in advance

Christos Karvounis
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