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Numerical investigation of kinetic turbulence in relativistic pair plasmas – I. Turbulence statistics

TitleNumerical investigation of kinetic turbulence in relativistic pair plasmas – I. Turbulence statistics
Publication TypeJournal Article
Year of Publication2017
AuthorsZhdankin, V, Uzdensky, DA, Werner, GR, Begelman, MC
JournalMonthly Notices of the Royal Astronomical Society
Volume474
Start Page2514
Issue2
Pagination2514 - 2535
Date Published2017-11
ISSN0035-8711
Abstract

We describe results from particle-in-cell simulations of driven turbulence in collisionless, magnetized, relativistic pair plasma. This physical regime provides a simple setting for investigating the basic properties of kinetic turbulence and is relevant for high-energy astrophysical systems such as pulsar wind nebulae and astrophysical jets. In this paper, we investigate the statistics of turbulent fluctuations in simulations on lattices of up to 10243 cells and containing up to 2 × 1011 particles. Due to the absence of a cooling mechanism in our simulations, turbulent energy dissipation reduces the magnetization parameter to order unity within a few dynamical times, causing turbulent motions to become sub-relativistic. In the developed stage, our results agree with predictions from magnetohydrodynamic turbulence phenomenology at inertial-range scales, including a power-law magnetic energy spectrum with index near −5/3, scale-dependent anisotropy of fluctuations described by critical balance, lognormal distributions for particle density and internal energy density (related by a 4/3 adiabatic index, as predicted for an ultra-relativistic ideal gas), and the presence of intermittency. We also present possible signatures of a kinetic cascade by measuring power-law spectra for the magnetic, electric and density fluctuations at sub-Larmor scales.

URLhttps://academic.oup.com/mnras/article/474/2/2514/4600561
DOI10.1093/mnras/stx2883