2020/02/05 by Antonios Nathanail, Christian M. Fromm, Oliver Porth +5 · 1 citation
Physics and Astronomy · #Accretion (finance) #Active galactic nucleus #Astrophysical Phenomena and Observations #Astrophysical jet #Astrophysics #Astrophysics and Cosmic Phenomena #Dissipation #Galaxy #Gamma-ray bursts and supernovae #Magnetic field #Magnetic reconnection #Magnetohydrodynamics #Physics #Plasmoid #Supermassive black hole #Torus #astro-ph.HE #gr-qc
paper · pdf · doi:10.1093/mnras/staa1165
17 pages, MNRAS submitted
arxiv created 2020/02/05 · openalex publication_date 2020/04/27 · arxiv updated 2020/06/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
ABSTRACT One of the main dissipation processes acting on all scales in relativistic jets is thought to be governed by magnetic reconnection. Such dissipation processes have been studied in idealized environments, such as reconnection layers, which evolve in merging islands and lead to the production of ‘plasmoids’, ultimately resulting in efficient particle acceleration. In accretion flows on to black holes, reconnection layers can be developed and destroyed rapidly during the turbulent evolution of the flow. We present a series of two-dimensional general-relativistic magnetohydrodynamic simulations of tori accreting on to rotating black holes focusing our attention on the formation and evolution of current sheets. Initially, the tori are endowed with a poloidal magnetic field having a multiloop structure along the radial direction and with an alternating polarity. During reconnection processes, plasmoids and plasmoid chains are developed leading to a flaring activity and hence to a variable electromagnetic luminosity. We describe the methods developed to track automatically the plasmoids that are generated and ejected during the simulation, contrasting the behaviour of multiloop initial data with that encountered in typical simulations of accreting black holes having initial dipolar field composed of one loop only. Finally, we discuss the implications that our results have on the variability to be expected in accreting supermassive black holes.