Particle Acceleration in Kink-unstable Jets

• Published in: Astrophysical journal. Letters Vol. 896; no. 2; p. L31
• Main Authors: Davelaar, Jordy, Philippov, Alexander A., Bromberg, Omer, Singh, Chandra B.
• Format: Journal Article
• Language: English
• Published: Austin The American Astronomical Society 01.06.2020; IOP Publishing
• Subjects: Activation; Active galactic nuclei; Current sheets; Electric fields; Evolution; First principles; Fluid dynamics; Free jets; Gamma ray bursts; Gamma rays; High energy astrophysics; Instability; Jets; Magnetohydrodynamic simulation; Magnetohydrodynamic turbulence; Magnetohydrodynamics; Particle acceleration; Particle accelerators; Particle in cell technique; Plasma astrophysics; Plasma jets; Plasma physics; Small-scale turbulence; Stability; Turbulence
• ISSN: 2041-8205; 2041-8213
• DOI: 10.3847/2041-8213/ab95a2

Magnetized jets in gamma-ray bursts and active galactic nuclei are thought to be efficient accelerators of particles; however, the process responsible for the acceleration is still a matter of active debate. In this work, we study the kink instability in non-rotating force-free jets using first-principle particle-in-cell simulations. We obtain similar overall evolution of the instability as found in magnetohydrodynamics simulations. The instability first generates large-scale current sheets, which at later times break up into small-scale turbulence. Reconnection in these sheets proceeds in the strong guide field regime, which results in a formation of steep power laws in the particle spectra. Later evolution shows heating of the plasma, which is driven by small-amplitude turbulence induced by the kink instability. These two processes energize particles due to a combination of ideal and non-ideal electric fields.