Energy transfer in compressible magnetohydrodynamic turbulence for isothermal self-gravitating fluids.

Phys Rev E

University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0424, USA.

Published: February 2018

AI Article Synopsis

  • The study explores three-dimensional magnetohydrodynamic turbulence in a self-gravitating, isothermal fluid, focusing on two-point statistics under high Reynolds numbers.
  • An alternative formulation allows for a clearer representation of total energy transfer, separating contributions from kinetic, magnetic, thermodynamic, and gravitational factors.
  • The findings indicate that while global rotation has no effect on energy flux rates, a uniform magnetic field plays a significant role, and compressible turbulence maintains some energy flux even in the case of simple alignments.

Article Abstract

Three-dimensional, compressible, magnetohydrodynamic turbulence of an isothermal, self-gravitating fluid is analyzed using two-point statistics in the asymptotic limit of large Reynolds numbers (both kinetic and magnetic). Following an alternative formulation proposed by Banerjee and Galtier [Phys. Rev. E 93, 033120 (2016)2470-004510.1103/PhysRevE.93.033120; J. Phys. A: Math. Theor. 50, 015501 (2017)1751-811310.1088/1751-8113/50/1/015501], an exact relation has been derived for the total energy transfer. This approach results in a simpler relation expressed entirely in terms of mixed second-order structure functions. The kinetic, thermodynamic, magnetic, and gravitational contributions to the energy transfer rate can be easily separated in the present form. By construction, the new formalism includes such additional effects as global rotation, the Hall term in the induction equation, etc. The analysis shows that solid-body rotation cannot alter the energy flux rate of compressible turbulence. However, the contribution of a uniform background magnetic field to the flux is shown to be nontrivial unlike in the incompressible case. Finally, the compressible, turbulent energy flux rate does not vanish completely due to simple alignments, which leads to a zero turbulent energy flux rate in the incompressible case.

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http://dx.doi.org/10.1103/PhysRevE.97.023107DOI Listing

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