Kinetic simulations of imbalanced turbulence in a relativistic plasma: Net flow and particle acceleration. Issue 3 (10th November 2021)

• Record Type: Journal Article
• Authors: Hankla, Amelia M; Zhdankin, Vladimir; Werner, Gregory R; Uzdensky, Dmitri A; Begelman, Mitchell C
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 509:Issue 3(2022)
• Page Start: 3826
• Page End: 3841
• Publication Date: 2021-11-10
• Subjects: acceleration of particles -- plasmas -- relativistic processes -- turbulence; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stab3209
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: Turbulent high-energy astrophysical systems often feature asymmetric energy injection: for instance, Alfvén waves propagating from an accretion disc into its corona. Such systems are 'imbalanced': the energy fluxes parallel and antiparallel to the large-scale magnetic field are unequal. In the past, numerical studies of imbalanced turbulence have focused on the magnetohydrodynamic regime. In this study, we investigate externally driven imbalanced turbulence in a collision-less, ultrarelativistically hot, magnetized pair plasma using 3D particle-in-cell (PIC) simulations. We find that the injected electromagnetic momentum efficiently converts into plasma momentum, resulting in net motion along the background magnetic field with speeds up to a significant fraction of lightspeed. This discovery has important implications for the launching of accretion disc winds. We also find that although particle acceleration in imbalanced turbulence operates on a slower time-scale than in balanced turbulence, it ultimately produces a power-law energy distribution similar to balanced turbulence. Our results have ramifications for black hole accretion disc coronae, winds, and jets.