Inverse energy transfer in decaying, three-dimensional, non-helical magnetic turbulence due to magnetic reconnection
Name
2007.07325.pdf
Description
Submitted version
Size
26.92 MB
Format
Adobe PDF
Checksum (MD5)
5188e81099fe53681915f18f97cf16b6
Author(s)
Bhat, Pallavi
Zhou, Muni
Loureiro, Nuno F
Date Issued
2021
Journal
Monthly Notices of the Royal Astronomical Society
Publisher
Oxford University Press (OUP)
Citation
Bhat, Pallavi, Zhou, Muni and Loureiro, Nuno F. 2021. "Inverse energy transfer in decaying, three-dimensional, non-helical magnetic turbulence due to magnetic reconnection." Monthly Notices of the Royal Astronomical Society, 501 (2).
Version
Original manuscript
Abstract
© 2021 2020 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society. It has been recently shown numerically that there exists an inverse transfer of magnetic energy in decaying, non-helical, magnetically dominated, magnetohydrodynamic turbulence in three dimensions (3D). We suggest that magnetic reconnection is the underlying physical mechanism responsible for this inverse transfer. In the two-dimensional (2D) case, the inverse transfer is easily inferred to be due to smaller magnetic islands merging to form larger ones via reconnection. We find that the scaling behaviour is similar between the 2D and 3D cases, i.e. the magnetic energy evolves as t-1, and the magnetic power spectrum follows a slope of k-2. We show that on normalizing time by the magnetic reconnection time-scale, the evolution curves of the magnetic field in systems with different Lundquist numbers collapse on to one another. Furthermore, transfer function plots show signatures of magnetic reconnection driving the inverse transfer. We also discuss the conserved quantities in the system and show that the behaviour of these quantities is similar between the 2D and 3D simulations, thus making the case that the dynamics in 3D could be approximately explained by what we understand in 2D. Lastly, we also conduct simulations where the magnetic field is subdominant to the flow. Here, too, we find an inverse transfer of magnetic energy in 3D. In these simulations, the magnetic energy evolves as t-1.4 and, interestingly, a dynamo effect is observed.
MIT Department
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
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Creative Commons Attribution-Noncommercial-Share Alike
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DOI of Published Version
https://doi.org/10.1093/MNRAS/STAA3849
