Rapid particle acceleration due to recollimation shocks and turbulent magnetic fields in injected jets with helical magnetic fields. Issue 2 (12th February 2020)

• Record Type: Journal Article
• Authors: Nishikawa, Kenichi; Mizuno, Yosuke; Gómez, Jose L; Duţan, Ioana; Niemiec, Jacek; Kobzar, Oleh; MacDonald, Nicholas; Meli, Athina; Pohl, Martin; Hirotani, Kouichi
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 493:Issue 2(2020)
• Page Start: 2652
• Page End: 2658
• Publication Date: 2020-02-12
• Subjects: acceleration of particles -- magnetic reconnection -- relativistic processes -- turbulence -- methods: numerical -- ISM: jets and outflows; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/staa421
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: One of the key questions in the study of relativistic jets is how magnetic reconnection occurs and whether it can effectively accelerate electrons in the jet. We performed 3D particle-in-cell (PIC) simulations of a relativistic electron–proton jet of relatively large radius that carries a helical magnetic field. We focused our investigation on the interaction between the jet and the ambient plasma and explore how the helical magnetic field affects the excitation of kinetic instabilities such as the Weibel instability (WI), the kinetic Kelvin–Helmholtz instability (kKHI), and the mushroom instability (MI). In our simulations these kinetic instabilities are indeed excited, and particles are accelerated. At the linear stage we observe recollimation shocks near the centre of the jet. As the electron–proton jet evolves into the deep non-linear stage, the helical magnetic field becomes untangled due to reconnection-like phenomena, and electrons are repeatedly accelerated as they encounter magnetic-reconnection events in the turbulent magnetic field.