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

[王东升]

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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