The work in this INCITE project takes a critical step toward understanding the behavior of black holes in the universe.
Accretion flows around supermassive black holes at the centers of galaxies emit electromagnetic radiation that is critical to understanding these active galactic nuclei, which influence galactic evolution. Interpreting observed radiation, however, requires detailed modeling of the complex multi-scale plasma processes in accretion flows. Using petascale 3D particle-in-cell simulations, this project investigates electron versus ion energization, nonthermal particle acceleration, and self-consistent synchrotron radiation for plasma processes likely ubiquitous in black-hole accretion, including plasma turbulence driven by the magnetorotational instability (MRI) or other forces, and collisionless magnetic reconnection.
The team has identified three key links in the chain of plasma processes that lead from the gravitational attraction of matter around a black hole to accretion and radiation. The development of the MRI leads to outward angular momentum transport that allows accretion; it also generates turbulence and current sheets leading to magnetic reconnection, both of which result in particle energization, hence also radiation.
The first-principles simulations of plasma processes and energy conversion mechanisms important in black hole accretion flows will be used to inform global magnetohydrodynamics computational and theoretical modeling, thus taking into account kinetic processes to predict radiation output for comparison to observations. Moreover, these kinetic simulations of 3D MRI turbulence and reconnection have the potential to significantly advance computational plasma physics.