ET Workshop Fall 2011 MHD

Current Status

• MHD implemented in "parallel" to non-MHD code in GRHydro
• Variables:
  • HydroBase: primitives
  • GRHydro: conservatives
• GRHydro: Calculate magnetic pressure in calculation of Tmunu, and store it
• Riemann: only HLLE and local Lax-Friedrich, no Roe, no Marquina (Bruno: HLLE)
• HLLC or HLLD should be better than HLLE
• Con2Prim
  • works for polytropic cases
  • all NR-based, only choice of variables
  • Multiple guesses sometime necessary: should be "supported"
• Bruno: divergence cleaning worked smoothly until merger
  • Putting everything in source-terms doesn't work well
• Whisky implements
  • contraint transport (problems with AMR)
  • divergence cleaning (not very well tested)
  • vector potential
    • at the center of the cell works, using KO-Dissipation
    • at the edge works as well (e.g. Zach Etienne), but requires special prolongation operators in Carpet -> not public