[ET Trac] [Einstein Toolkit] #1974: Add WVUThorns_Diagnostics to the ET

Einstein Toolkit trac-noreply at einsteintoolkit.org
Mon Oct 24 10:28:08 CDT 2016

#1974: Add WVUThorns_Diagnostics to the ET
 Reporter:  zachetie@…          |       Owner:                     
     Type:  enhancement         |      Status:  new                
 Priority:  unset               |   Milestone:                     
Component:  Other               |     Version:  development version
 Keywords:                      |  
 I have open-sourced a very useful set of diagnostic routines for GRMHD,
 GRHD, and even vacuum simulations.

 The thorns are available here:

 Here's a brief description of each thorn:
 Brief description of included thorns

 '''Seed_Magnetic_Fields-modified''' Extended Seed_Magnetic_Fields thorn
 for binary neutron stars. Supercedes Seed_Magnetic_Fields thorn.

 '''Meudon_Bin_NS-modified''' Modifications to Meudon BNS initial data
 thorn to disable the overwriting of initial lapse/shift, which acts to
 significantly reduce coordinate eccentricity. Supercedes Meudon_Bin_NS

 '''VolumeIntegrals_GRMHD''' Nice GRMHD volume integration thorn, currently
 depends on IllinoisGRMHD and Carpet. Performs volume integrals on
 arbitrary "Swiss-cheese"-like topologies, and even interoperates with
 Carpet to track NS centers of mass.

 '''VolumeIntegrals_vacuum''' Nice GRMHD volume integration thorn,
 currently depends on ML_BSSN. There is a bit of code duplication and
 duplicated functionality between VI_GRMHD and VI_vacuum, to ensure that
 VI_vacuum can be used without enabling a GRMHD code. There is probably a
 better way of doing this, but I haven't had the time to think deeply about

 '''particle_tracerET''' Solves the ODE \partial_t x^i = v^i for typically
 thousands of tracer particles, using an RK4 integration atop the current
 timestepping. E.g., one RK4 substep in the particle integration might
 occur every 16 RK4 substeps in the GRMHD evolution. These tracer particle
 positions are quite useful for visualizing magnetic field lines in a
 consistent way from frame-to-frame in a movie (recall that in the GRMHD
 approximation, the magnetic field lines stay attached the fluid elements
 they thread ["Flux Freezing"]). Note that the velocity must be consistent
 with the velocity appearing in the GRMHD induction equation. This thorn
 reads in the HydroBase vel[] vector gridfunction, which assumes the
 Valencia formalism, and converts it into the induction equation velocity.

 '''smallbPoynET''' Computes b^i^, b^2^, and three spatial components of
 Poynting flux. It also computes (-1-u,,0,,), which is useful for tracking
 unbound matter.

Ticket URL: <https://trac.einsteintoolkit.org/ticket/1974>
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