Dynamic Alignment and Plasmoid Formation in Relativistic Magnetohydrodynamic Turbulence
Abstract We present high-resolution 2D and 3D simulations of magnetized decaying turbulence in relativistic, resistive magnetohydrodynamics. The simulations show dynamic formation of large-scale intermittent long-lived current sheets being disrupted into plasmoid chains by the tearing instability. These current sheets are locations of enhanced magnetic-field dissipation and heating of the plasma. We find magnetic energy spectra ∝ k −3/2 , together with strongly pronounced dynamic alignment of Elsässer fields and of velocity and magnetic fields, for strong guide-field turbulence, whereas we retrieve spectra ∝ k −5/3 for the case of a weak guide-field.
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Award ID(s):
Publication Date:
NSF-PAR ID:
10353613
Journal Name:
The Astrophysical Journal Letters
Volume:
923
Issue:
1
Page Range or eLocation-ID:
L13
ISSN:
2041-8205
We present a phenomenological and numerical study of strong Alfvénic turbulence in a magnetically dominated collisionless relativistic plasma with a strong background magnetic field. In contrast with the nonrelativistic case, the energy in such turbulence is contained in magnetic and electric fluctuations. We argue that such turbulence is analogous to turbulence in a strongly magnetized nonrelativistic plasma in the regime of broken quasi-neutrality. Our 2D particle-in-cell numerical simulations of turbulence in a relativistic pair plasma find that the spectrum of the total energy has the scalingk−3/2, while the difference between the magnetic and electric energies, the so-called residual energy, has the scalingk−2.4. The electric and magnetic fluctuations at scaleexhibit dynamic alignment with the alignment angle scaling close to$cosϕℓ∝ℓ1/4$. At scales smaller than the (relativistic) plasma inertial scale, the energy spectrum of relativistic inertial Alfvén turbulence steepens tok−3.5.