[FLASH-USERS] ensuring div B = 0 when adjusting evolution

[Sean M. Couch]

Hi Jon,

Can you give a little more info? Are you using the USM solver? Are you using AMR? Have you actually checked that divB>0 in the output data? A log file from a representative run would be useful.

In my experience, the USM solver in cylindrical R-Z coordinates with AMR can be….touchy. But it should work and maintain divB=0! (See, e.g., http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013ApJ...773..136J&link_type=EJOURNAL).

Cheers,
Sean


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Sean M. Couch
Assistant Professor
Department of Physics and Astronomy
Department of Computational Mathematics, Science, and Engineering
National Superconducting Cyclotron Laboratory/Facility for Rare Isotope Beams
Michigan State University
567 Wilson Rd, 3250 BPS
East Lansing, MI  48824
(517) 884-5035    ——    couch at pa.msu.edu<mailto:couch at pa.msu.edu>    ——    www.pa.msu.edu/~couch<http://www.pa.msu.edu/~couch>





On May 25, 2017 at 4:41:45 PM, Slavin, Jonathan (jslavin at cfa.harvard.edu<mailto:jslavin at cfa.harvard.edu>) wrote:

Hi all,

I'm running MHD simulations where I set off a second supernova explosion within a pre-existing remnant.  I'm using Simulation_adjustEvolution for this.  However, I'm running into a problem with the magnetic field just after initiating the second explosion.  I'm getting very large pixel-to-pixel variations in Bx and By at the edge of the new expanding blast wave.  I'm thinking that it could be because of non-zero div B in the region in which the explosion is generated. So my question is, does anyone have a suggestion for div B cleaning at the point that the explosion is started, i.e. within Simulation_adjustEvolution, to prevent the problems I'm having? I don't really expect the B field to be dynamically important inside the remnant (beta >> 1), so accuracy of the B field is probably not important there.  I should add that I'm doing these calculations in 2D cylindrical symmetry (R-Z).  Thanks in advance for any help.

Regards,
Jon

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Jonathan D. Slavin                 Harvard-Smithsonian CfA
jslavin at cfa.harvard.edu<mailto:jslavin at cfa.harvard.edu>       60 Garden Street, MS 83
phone: (617) 496-7981       Cambridge, MA 02138-1516
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