[FLASH-USERS] Diffusion problem of angular magnetic field in one dimension

[Hansen, Eddie]

Hi Wang,

Have you plotted the species variables (fill, line, vacu) to make sure you still have vacuum in the domain? It would also be good to check the resistivity (res2).

It’s hard to tell what might be going wrong without more info. Can you send the par file?

--
Eddie Hansen
Research Scientist
Flash Center for Computational Science


From: flash-users <flash-users-bounces at flash.rochester.edu> on behalf of 王东升 <wangdswork at stu.xjtu.edu.cn>
Date: Thursday, April 27, 2023 at 1:19 PM
To: flash-users <flash-users at flash.rochester.edu>
Subject: [FLASH-USERS] Diffusion problem of angular magnetic field in one dimension
Dear FLASH user & developers,
    I have a question about implicit magnetic diffusion in FLASH4.7. I wanted to observe the diffusion of angular magnetic field in one dimension, so I set the fluid velocity to zero in the "Simulation_adjustEvolution.F90" file to rule out the magnetic freezing effect. However, I found that the magnetic field diffused slowly in vacuum, which is quite different from the result of a paper I saw. I have attached the comparison diagram of the two results.
    The vacuum resistivity I set is 1e9(cm2/s), and the vacuum region is between 0.8 and 1cm. I modified it on the Z-Pinch file, and the current was set to 1MA.
    I would appreciate any help.
    Thanks!
Best,
Wang Dongsheng
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