COMPRESSIBLE RELATIVISTIC MAGNETOHYDRODYNAMIC TURBULENCE IN MAGNETICALLY DOMINATED PLASMAS AND IMPLICATIONS FOR A STRONG-COUPLING REGIME

Journal Article · Thu Nov 10 00:00:00 EST 2016 · Astrophysical Journal Letters

DOI:https://doi.org/10.3847/2041-8205/831/2/L11· OSTI ID:22654168

Takamoto, Makoto ^[1]; Lazarian, Alexandre ^[2]

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1. Department of Earth and Planetary Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033 (Japan)
2. Department of Astronomy, University of Wisconsin, 475 North Charter Street, Madison, WI 53706 (United States)

In this Letter, we report compressible mode effects on relativistic magnetohydrodynamic (RMHD) turbulence in Poynting-dominated plasmas using three-dimensional numerical simulations. We decomposed fluctuations in the turbulence into 3 MHD modes (fast, slow, and Alfvén) following the procedure of mode decomposition in Cho and Lazarian, and analyzed their energy spectra and structure functions separately. We also analyzed the ratio of compressible mode to Alfvén mode energy with respect to its Mach number. We found the ratio of compressible mode increases not only with the Alfvén Mach number, but also with the background magnetization, which indicates a strong coupling between the fast and Alfvén modes. It also signifies the appearance of a new regime of RMHD turbulence in Poynting-dominated plasmas where the fast and Alfvén modes are strongly coupled and, unlike the non-relativistic MHD regime, cannot be treated separately. This finding will affect particle acceleration efficiency obtained by assuming Alfvénic critical-balance turbulence and can change the resulting photon spectra emitted by non-thermal electrons.

• OSTI ID: 22654168
• Journal Information: Astrophysical Journal Letters, Vol. 831, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ACCELERATION
ALFVEN WAVES
COMPUTERIZED SIMULATION
EFFICIENCY
ELECTRONS
EMISSION
ENERGY SPECTRA
FLUCTUATIONS
MACH NUMBER
MAGNETIC FIELDS
MAGNETIZATION
MAGNETOHYDRODYNAMICS
PHOTONS
PLASMA
RELATIVISTIC RANGE
STRONG-COUPLING MODEL
STRUCTURE FUNCTIONS
THREE-DIMENSIONAL CALCULATIONS
TURBULENCE