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That B-field might be diffusing away quickly if your setup still has high resistivity in the ‘vacu’ region. The ZPinch problem is really only designed to work in cylindrical geometry, and we do not currently support running Z-pinches in Cartesian.
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<div><b>Eddie Hansen</b></div>
<div>Applications Group Leader</div>
<div>Flash Center for Computational Science</div>
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<div>On May 8, 2026, at 2:51 PM, Adam F Kowalski <Adam.F.Kowalski@Colorado.EDU> wrote:</div>
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Dear FLASH users,</div>
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I am starting from the magnetoHD/ZPinch example using cartesian coordinates and no circuit with the following switches:</div>
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-auto -2d +cartesian +pm4dev +usm3t +mtmmmt species=fill,line,vacu +mgd mgd_meshgroups=6 </div>
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I am imposing my own constant magnetic field in the Y-direction in Siminulation_initBlock.F90 by simply setting MAGY_VAR. However, the imposed magnetic field disappears after the initial time step. Do you know what I am doing wrong? Working with the MHD
blast wave BlastBS simulation, the imposed magnetic field set in Simulation_initBlock.F90 does not go away after the initial timestep.</div>
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Thank you and I apologize if this is a very naive question,</div>
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Adam K.</div>
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