[FLASH-USERS] Negative Internal Energies in the 2D, AMR, Z-Pinch problem

[Sutcliffe, Graeme]

Hi Paul,

You can try the following par file options if you haven't already, which helped me to get some laserslab runs working back in FLASH4.7 (adjust accordingly if you're not doing a 3T sim):
dr_usePOSdefComputeDt = .true.
dr_posdefdtfactor = 0.1
dr_numPosdefVars = 3
dr_posdefVar_1 = "eele"
dr_posdefVar_2 = "eion"
dr_posdefVar_3 = "erad"

The dr_posdefdtfactor of 0.1 might be a bit aggressive (i.e. too small), I haven't played with it.

Graeme
________________________________
From: flash-users <flash-users-bounces at flash.rochester.edu> on behalf of Paul Campbell <Paul.Campbell at zap.energy>
Sent: Tuesday, November 5, 2024 1:37 PM
To: flash-users at flash.rochester.edu <flash-users at flash.rochester.edu>
Subject: [FLASH-USERS] Negative Internal Energies in the 2D, AMR, Z-Pinch problem


Hello,



I am attempting to get the 2D Z-pinch problem working with AMR but have been unable to get the sim to run without crashing .  From the logs, I appear to be running into many negative internal energy warnings.  It looks like both the electron and ion temperatures/energies need to be continuously corrected.  To try and address this issue, I have tried refining on density, electron, and ion temperatures but the warnings persist.  In terms of the AMR settings, I am using a 32x32 grid with 4x4 cells, a lrefine_max=4, and I have left the refinement cutoffs and filters unchanged from default.  My questions are:



  1.  Is this an issue with the AMR settings, would a finer grid fix this problem?
  2.  Should I be refining on different parameters?
  3.  Is this an issue with a non-AMR setting?



Paul Campbell



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