TY - JOUR
T1 - Kinetic Turbulence in Collisionless High- β Plasmas
AU - Arzamasskiy, Lev
AU - Kunz, Matthew W.
AU - Squire, Jonathan
AU - Quataert, Eliot
AU - Schekochihin, Alexander A.
N1 - Funding Information:
This work benefited from useful conversations with Christopher Chen, Jeremy Goodman, Kristopher Klein, Yuan Li, Christopher Reynolds, Anatoly Spitkovsky, James Stone, Vladimir Zhdankin, Ellen Zweibel, and especially Silvio Sergio Cerri and Archie Bott. Assistance from Daniel Grošelj with computing structure functions is gratefully acknowledged. L. A. was supported by the National Aeronautics and Space Administration (NASA) under Grant No. NNX17AK63G issued through the Astrophysical Theory Program, a Harold W. Dodds Honorific Fellowship from Princeton University, and the Institute for Advanced Study. Support for M. W. K. was provided by NASA Grant No. NNX17AK63G and Department of Energy (DOE) Award No. DE-SC0019046 through the NSF/DOE Partnership in Basic Plasma Science and Engineering. Support for J. S. was provided by Rutherford Discovery Fellowship RDF-U001804 and Marsden Fund Grant No. UOO1727, which are managed through the Royal Society Te Apārangi. E. Q. was supported in part by a Simons Investigator award from the Simons Foundation. The work of A. A. S. was supported in part by the UK EPSRC Grant No. EP/R034737/1 and the UK STFC Grant No. ST/W000903/1. High-performance computing resources were provided by the Texas Advanced Computer Center at The University of Texas at Austin under allocation numbers TG-AST160068 and AST130058, and the PICSciE-OIT TIGRESS High Performance Computing Center and Visualization Laboratory at Princeton University. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by NSF Grant No. ACI-1548562.
Publisher Copyright:
© 2023 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
PY - 2023/4
Y1 - 2023/4
N2 - We present results from three-dimensional hybrid-kinetic simulations of Alfvénic turbulence in a high-β, collisionless plasma. The key feature of such turbulence is the interplay between local wave-wave interactions between the fluctuations in the cascade and the nonlocal wave-particle interactions associated with kinetic microinstabilities driven by anisotropy in the thermal pressure (namely, firehose, mirror, and ion cyclotron). We present theoretical estimates for, and calculate directly from the simulations, the effective collisionality and plasma viscosity in pressure-anisotropic high-β turbulence, demonstrating that, for strong Alfvénic turbulence, the effective parallel-viscous scale is comparable to the driving scale of the cascade. Below this scale, the kinetic-energy spectrum indicates an Alfvénic cascade with a slope steeper than -5/3 due to the anisotropic viscous stress. The magnetic-energy spectrum is shallower than -5/3 near the ion-Larmor scale due to fluctuations produced by the firehose instability. Most of the cascade energy (≈80%-90%) is dissipated as ion heating through a combination of Landau damping and anisotropic viscous heating. Our results have implications for models of particle heating in low-luminosity accretion onto supermassive black holes, the effective viscosity of the intracluster medium, and the interpretation of near-Earth solar-wind observations.
AB - We present results from three-dimensional hybrid-kinetic simulations of Alfvénic turbulence in a high-β, collisionless plasma. The key feature of such turbulence is the interplay between local wave-wave interactions between the fluctuations in the cascade and the nonlocal wave-particle interactions associated with kinetic microinstabilities driven by anisotropy in the thermal pressure (namely, firehose, mirror, and ion cyclotron). We present theoretical estimates for, and calculate directly from the simulations, the effective collisionality and plasma viscosity in pressure-anisotropic high-β turbulence, demonstrating that, for strong Alfvénic turbulence, the effective parallel-viscous scale is comparable to the driving scale of the cascade. Below this scale, the kinetic-energy spectrum indicates an Alfvénic cascade with a slope steeper than -5/3 due to the anisotropic viscous stress. The magnetic-energy spectrum is shallower than -5/3 near the ion-Larmor scale due to fluctuations produced by the firehose instability. Most of the cascade energy (≈80%-90%) is dissipated as ion heating through a combination of Landau damping and anisotropic viscous heating. Our results have implications for models of particle heating in low-luminosity accretion onto supermassive black holes, the effective viscosity of the intracluster medium, and the interpretation of near-Earth solar-wind observations.
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U2 - 10.1103/PhysRevX.13.021014
DO - 10.1103/PhysRevX.13.021014
M3 - Article
AN - SCOPUS:85153858305
SN - 2160-3308
VL - 13
JO - Physical Review X
JF - Physical Review X
IS - 2
M1 - 021014
ER -