@article{672628a035e2431ab26e1ead8a5702cb,
title = "Weak Alfv{\'e}nic turbulence in relativistic plasmas II: Current sheets and dissipation",
abstract = "Alfv{\'e}n waves as excited in black hole accretion disks and neutron star magnetospheres are the building blocks of turbulence in relativistic, magnetized plasmas. A large reservoir of magnetic energy is available in these systems, such that the plasma can be heated significantly even in the weak turbulence regime. We perform high-resolution three-dimensional simulations of counter-propagating Alfv{\'e}n waves, showing that an energy spectrum develops as a result of the weak turbulence cascade in relativistic magnetohydrodynamics and its infinitely magnetized (force-free) limit. The plasma turbulence ubiquitously generates current sheets, which act as locations where magnetic energy dissipates. We show that current sheets form as a natural result of nonlinear interactions between counter-propagating Alfv{\'e}n waves. These current sheets form owing to the compression of elongated eddies, driven by the shear induced by growing higher-order modes, and undergo a thinning process until they break-up into small-scale turbulent structures. We explore the formation of current sheets both in overlapping waves and in localized wave packet collisions. The relativistic interaction of localized Alfv{\'e}n waves induces both Alfv{\'e}n waves and fast waves, and efficiently mediates the conversion and dissipation of electromagnetic energy in astrophysical systems. Plasma energization through reconnection in current sheets emerging during the interaction of Alfv{\'e}n waves can potentially explain X-ray emission in black hole accretion coronae and neutron star magnetospheres.",
keywords = "MHD turbulence, computational methods, transition to turbulence, turbulence simulation",
author = "B. Ripperda and Mahlmann, {J. F.} and A. Chernoglazov and Tenbarge, {J. M.} and Most, {E. R.} and J. Juno and Y. Yuan and Philippov, {A. A.} and A. Bhattacharjee",
note = "Funding Information: We acknowledge the Flatiron's Center for Computational Astrophysics and the Princeton Plasma Physics Laboratory for support of collaborative CCA–PPPL meetings on plasma-astrophysics where the ideas presented in this paper have been initiated. The computational resources and services used in this work were provided by facilities supported by the Scientific Computing Core at the Flatiron Institute, a division of the Simons Foundation; and by the VSC (Flemish Supercomputer Center), funded by the Research Foundation Flanders (FWO) and the Flemish Government department EWI. The calibration of ET-FFE was in part conducted on resources of the Barcelona Supercomputing Center (AECT-2021-1-0006). B.R. is supported by a Joint Princeton/Flatiron Postdoctoral Fellowship. A.A.P. and J.F.M. acknowledge support by the National Science Foundation under Grant No. AST-1909458. E.R.M. gratefully acknowledges support from a joint fellowship at the Princeton Center for Theoretical Science, the Princeton Gravity Initiative and the Institute for Advanced Study. J.M.T. and A.B. acknowledge support by the Simons Foundation. A.C. gratefully acknowledges support and hospitality from the Simons Foundation through the pre-doctoral program at the Center for Computational Astrophysics, Flatiron Institute. J.J. is supported by a NSF Atmospheric and Geospace Science Postdoctoral Fellowship (Grant No. AGS-2019828). Y.Y. is supported by a Flatiron Research Fellowship at the Flatiron Institute, Simons Foundation. Research at the Flatiron Institute is supported by the Simons Foundation. We thank Gregory Howes, Joonas N{\"a}ttil{\"a}, Andrei Beloborodov, Daniel Groselj, Fabio Bacchini and Lev Arzamasskiy for useful discussions. B.R. and J.F.M. contributed equally to this work. Publisher Copyright: Copyright {\textcopyright} The Author(s), 2021. Published by Cambridge University Press.",
year = "2021",
month = oct,
day = "3",
doi = "10.1017/S0022377821000957",
language = "English (US)",
volume = "87",
journal = "Journal of Plasma Physics",
issn = "0022-3778",
publisher = "Cambridge University Press",
number = "5",
}