Relativistic Astrophysics Plasma Simulations

2D magnetised torus simulations with AMR by BHAC

In order to investigate the dynamical phenomena of relativistic compact objects, the numerical tools of computing relativistic plasma considering general relativistic effect are needed. I have developed new general-relativistic magnetohydrodynamic (GRMHD) code RAISHIN using high-resolution shock-capturing schemes (Mizuno et al. 2006, 2011). It has second-order numerical accuracy and is applied to the most of my simulation studies. In 2013, the RAISHIN code is extended to handle resistivity for the physical treatment of relativistic magnetic reconnection (Mizuno 2013). From 2014, I have participated to develop state-of-art new 3D adaptive mesh refinement (AMR) GRMHD code BHAC (Porth et al. 2017). I have presented the ability of AMR in recoiling black hole simulations to capture the spiral shock structure in the accretion disk efficiently (Meliani et al. 2017). We have implemented new staggered-mesh higher-order constraint transport method for handling divergence free magnetic field in AMR simulations to BHAC code (Olivares et al. 2019). BHAC code has well constructed by modular design. In EHT Collaboration, BHAC code is established as a standard GRMHD code in the collaboration (Porth et al. 2019).

RAISHIN code is currently private use. But I will provide the code upon request (and hope future collaboration). BHAC code is publicly available in basic version.

BHAC website:

BHAC Developer’s version is used under collaboration. If you want to collaborate with me using BHAC code, please contact me.

The plasma particle simulation using Relativistic Particle-in-Cell (PIC) code shows different physical behaviour than macro-scale RMHD simulations in relativistic astrophysics. PIC simulations handle the micro-physics of plasma including kinetic effect which can not handle in MHD simulations and apply to investigate the kinetic effects of plasma (kinetic plasma instability, particle acceleration) in relativistic flow, shocks, and relativistic magnetic reconnection. I have been used 3D RPIC code TRISTAN-MPI developed by Ken-Ichi Nishikawa (e.g., Nishikawa et al. 2021).