<div dir="ltr"><div dir="ltr">Hi Matthew! <div>The answer to your questions is: it depends. </div><div>In order to include "standard" magnetic resistivity in your simulation (see the section 15.3.5.3, user guide release 4.8), </div><div>you need to set up the runtime parameters: </div><div><font face="monospace"><i>useDiffuse            =.true.<br>useMagneticResistivity=.true.<br>resistivity           =some_value </i></font><br></div><div><br></div><div>And to choose among the available implementations, e.g.: the ”Constant” version, ”SpitzerHighZ”, as well as the ”DaviesWen”. </div><div>For which you need to add the right path in the Config file, e.g.: </div><div><br></div><div><i><font face="monospace"># For Constant resistivity<br>REQUIRES physics/materialProperties/MagneticResistivity/MagneticResistivityMain/Constant</font></i></div><div><i><font face="monospace"><br># For SpitzerHighZ resistivity<br>REQUIRES physics/materialProperties/MagneticResistivity/MagneticResistivityMain/SpitzerHighZ<br><br></font></i></div><div><i><font face="monospace"># For DaviesWen resistivity</font></i></div><div><i><font face="monospace">REQUIRES physics/materialProperties/MagneticResistivity/MagneticResistivityMain/DaviesWen</font></i></div><div><br></div><div>But, you may also want to consider <b>"extended MHD" </b>(see section 15.3.5). With this you can consider more MHD effects: </div><div>Hall, Biermann battery, anisotropic magnetic resistivity, Seebeck, Nernst, and cross-field terms. </div><div>The runtime parameter <span style="color:rgb(50,48,57);text-align:justify"><font face="monospace">useCrossMagRes</font></span><span style="color:rgb(50,48,57);font-family:arial,sans-serif;text-align:justify"> enable/disable the anisotropic magnetic resistivity. </span></div><div><span style="color:rgb(50,48,57);font-family:arial,sans-serif;text-align:justify"><br></span></div><div><span style="color:rgb(50,48,57);font-family:arial,sans-serif;text-align:justify">So, if you want to include </span>anisotropic magnetic resistivity in your simulation, you need to enable <span style="color:rgb(50,48,57);font-family:monospace;text-align:justify">useCrossMagRes</span><span style="color:rgb(50,48,57);text-align:justify"><font face="arial, sans-serif">, </font></span></div><div><span style="color:rgb(50,48,57);text-align:justify"><font face="arial, sans-serif">otherwise you don't</font></span><span style="color:rgb(50,48,57);font-family:monospace;text-align:justify">. </span></div><div><span style="color:rgb(50,48,57);font-family:monospace;text-align:justify"><br></span></div><div><span style="color:rgb(50,48,57);text-align:justify"><font face="arial, sans-serif">Best. </font></span></div><div><span style="color:rgb(50,48,57);text-align:justify"><font face="arial, sans-serif">Ernesto. </font></span></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, 30 Jan 2026 at 10:33, Matthew Trantham <<a href="mailto:mtrantha@umich.edu" target="_blank">mtrantha@umich.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Dear <span><span>Users</span></span> and Developers,<div><br></div><div><span style="background-color:rgb(255,255,255)"><font face="arial, sans-serif">I am confused regarding the implementation of resistive MHD. In the manual, it implies that you need to use the term </font></span><span style="color:rgb(50,48,57);font-family:arial,sans-serif;text-align:justify">useCrossMagRes</span><span style="background-color:rgb(255,255,255)"><font face="arial, sans-serif"><span style="color:rgb(50,48,57);text-align:justify"> = .true., but without the Hall, this is turned off by the code.  I also noticed that example problems like ZPinch don't use this term (</span></font></span><span style="color:rgb(50,48,57);font-family:arial,sans-serif;text-align:justify">useCrossMagRes). Is it needed?</span></div></div>
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