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Updated: Jul 26, 2025
06:42
Magnetically Induced Rotating Rayleigh-Taylor Instability
Published on: March 3, 2017
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Parameter study of decaying magnetohydrodynamic turbulence
Andres Armua1, Arjun Berera1, Jaime Calderón-Figueroa1
1School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom.
Physical Review. E
|June 17, 2023
Summary
Helical and nonhelical magnetohydrodynamic (MHD) turbulence simulations reveal minimal inverse energy transfer, influenced by Prandtl number. Decaying laws depend on Prandtl and Reynolds numbers, not scale separation.
Area of Science:
- Physics
- Astrophysics
- Fluid Dynamics
Background:
- Helical magnetohydrodynamic (MHD) turbulence is known for inverse energy transfer due to magnetic helicity conservation.
- Recent studies suggest inverse energy transfer may occur in nonhelical MHD flows.
Purpose of the Study:
- Investigate inverse energy transfer in both helical and nonhelical MHD flows.
- Analyze the decaying laws of MHD turbulence across various parameters.
- Compare simulation results with existing literature.
Main Methods:
- Direct numerical simulations (DNS) of MHD turbulence.
- Extensive parameter study including Prandtl number (Pm) and Reynolds number (Re).
- Analysis of energy transfer and decay rates.
Main Results:
- A small inverse energy transfer was observed, increasing with the Prandtl number.
- Decaying laws (E~t^{-p}) were found to be independent of scale separation, depending only on Pm and Re.
- In helical cases, decay exponent p_b showed a dependence on Re (p_b ≈ 0.6 + 14/Re).
Conclusions:
- The Prandtl number plays a role in inverse energy transfer in MHD turbulence.
- Findings have implications for understanding cosmic magnetic field evolution.
- Decay characteristics are primarily governed by fluid properties (Pm, Re) rather than flow geometry.
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