[FLASH-USERS] Resistive MHD question

[Dennis Duffin]

Hello all,

I have a Resistive MHD question.

I'm playing with a custom built module modeled after the resistive MHD
stuff in FLASH2.5.  The non-ideal physics I'm playing with is mainly
ambipolar diffusion (which kinda looks like ohmic diffusion).  

Anyhow, midway through the simulation the run will crash (getting
negative densities; though even if I make these positive it will crash
on the same step).  I have no idea why.

One thing I forgot to add were the divB terms and I noticed that the
ohmic diffusion module includes them (as the MHD method is not assuming
divB = 0).  Is there any chance this could cause my program to crash
(note:  I will soon find out, but there are no div B anomalies in my
crashed run.)???

However, if anything else pops to mind I appreciate the input!  I
figure similar things may have happened in ohmic diffusion runs.  

thanks for any help!
Dennis