[FLASH-USERS] radiation in MHD blast wave example

[Hansen, Eddie]

Hi Adam,

RadFLAH refers to Radiation Flux-Limiter Aware Hydro. It uses the code in HydroMain/unsplit_rad, which is a variant of the more widely-used unsplit Hydro implementation in HydroMain/unsplit. It adds terms to the hydro equations to treat radiation differently, and it is enabled with the setup shortcut +uhd3tR. It only uses 1 radiation group, MHD is not fully implemented, and it generally has had limited use. We do not recommend this implementation for most HEDP problems.

You will have better luck with the more widely-used unsplit Hydro implementation with staggered mesh MHD (setup shortcut +usm3t), and then you can also use implicit MGD for radiation transport (+mgd mgd_meshgroups=<your_number_of_radiation_groups>).

--
Eddie Hansen
Applications Group Leader
Flash Center for Computational Science


From: flash-users <flash-users-bounces at flash.rochester.edu> on behalf of Adam F Kowalski <Adam.F.Kowalski at Colorado.EDU>
Date: Tuesday, May 13, 2025 at 11:25 PM
To: flash-users <flash-users at flash.rochester.edu>
Subject: [FLASH-USERS] radiation in MHD blast wave example
Dear Flash users,

I'm trying to incorporate radiation into the MHD blast wave example (35.2.8 of manual).  I see the note about RadFLAH / MGD not yet ready for MHD (Section 15.4).  Is radiation with magnetic fields currently not possible?  When I try, I get an error with the temperature returned by the Eos (coincidentally, a similar problem when I try the radiating blast wave example 35.9.2 with a -2d switch on).

Thanks very much,
Adam Kowalski
Associate Professor CU Boulder

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