Hello Chia-Hui,
- It is GRMHD code so that it should be able to consider magnetic
field. Is magnetic field considered in the gallery example of BNS? Because I did not see the relevant output data.
I do not think there is an explicit magnetised BNS example in the gallery. There is a single magnetised star in the runs we did for the GRHydro MHD paper, for which you can find the parameter file here: https://www.einsteintoolkit.org/mp.html in the magnetized TOV parfile https://www.einsteintoolkit.org/publications/2013_MHD/par/tov/tov8m3.par
A binary could likely be set up similarly. You can also try and see if IllinoisGRMHD (part of the Einstein Toolkit) has parameter files for this situation.
- I would like to simulate r-process in the future, is GRHydro
capable of it ? Because time scale for r-process is much larger than BNS merger, so maybe I will need other thorn ?
There is no nucleosynthesis code available in the Einstein Toolkit. For postprocessing you could have a look at Jonas Lippuner's SkyNet code: http://jonaslippuner.com/research/skynet/ which was used to postprocess data from supernova simulations using the Einstein Toolkit https://arxiv.org/abs/1712.09370
It is likely too slow (since it contains too many species) to directly use it during evolution (and there is no equation of state implemented right now that would allow for multiple species in the gas, though you may ask around in the list of someone has implemented anything they would be willing to share).
Yours, Roland