Mechanism for sequestering magnetic energy at large scales in shear-flow turbulence
| Autor: | B. Tripathi, A. E. Fraser, P. W. Terry, E. G. Zweibel, M. J. Pueschel |
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| Přispěvatelé: | Science and Technology of Nuclear Fusion |
| Rok vydání: | 2022 |
| Předmět: |
Plasma Physics (physics.plasm-ph)
Astrophysics - Solar and Stellar Astrophysics Astrophysics of Galaxies (astro-ph.GA) Fluid Dynamics (physics.flu-dyn) FOS: Physical sciences Physics - Fluid Dynamics Condensed Matter Physics Astrophysics - Astrophysics of Galaxies Physics - Plasma Physics Solar and Stellar Astrophysics (astro-ph.SR) |
| Zdroj: | Physics of Plasmas, 29, 070701 Physics of Plasmas, 29(7):070701. American Institute of Physics |
| ISSN: | 1070-664X |
| Popis: | Straining of magnetic fields by large-scale shear flow, generally assumed to lead to intensification and generation of small scales, is re-examined in light of the persistent observation of large-scale magnetic fields in astrophysics. It is shown that, in magnetohydrodynamic turbulence, unstable shear flows have the unexpected effect of sequestering magnetic energy at large scales, due to counteracting straining motion of nonlinearly excited large-scale stable eigenmodes. This effect is quantified via dissipation rates, energy transfer rates, and visualizations of magnetic field evolution by artificially removing the stable modes. These analyses show that predictions based upon physics of the linear instability alone miss substantial dynamics, including those of magnetic fluctuations. Comment: Accepted for publication in Physics of Plasmas as a Letter; A simulation movie embedded in Fig. 4 |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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