Multi-scale dynamics of magnetic flux tubes and inverse magnetic energy transfer
© 2020 The Author(s). Published by Cambridge University Press. We report on an analytical and numerical study of the dynamics of a three-dimensional array of identical magnetic flux tubes in the reduced-magnetohydrodynamic description of the plasma. We propose that the long-time evolution of this sy...
| Main Authors: | , , |
|---|---|
| Other Authors: | |
| Format: | Article |
| Language: | English |
| Published: |
Cambridge University Press (CUP)
2021
|
| Online Access: | https://hdl.handle.net/1721.1/135457 |
| _version_ | 1826208721030610944 |
|---|---|
| author | Zhou, Muni Loureiro, Nuno F Uzdensky, Dmitri A |
| author2 | Massachusetts Institute of Technology. Plasma Science and Fusion Center |
| author_facet | Massachusetts Institute of Technology. Plasma Science and Fusion Center Zhou, Muni Loureiro, Nuno F Uzdensky, Dmitri A |
| author_sort | Zhou, Muni |
| collection | MIT |
| description | © 2020 The Author(s). Published by Cambridge University Press. We report on an analytical and numerical study of the dynamics of a three-dimensional array of identical magnetic flux tubes in the reduced-magnetohydrodynamic description of the plasma. We propose that the long-time evolution of this system is dictated by flux-tube mergers, and that such mergers are dynamically constrained by the conservation of the pertinent (ideal) invariants, viz. the magnetic potential and axial fluxes of each tube. We also propose that in the direction perpendicular to the merging plane, flux tubes evolve in a critically balanced fashion. These notions allow us to construct an analytical model for how quantities such as the magnetic energy and the energy-containing scale evolve as functions of time. Of particular importance is the conclusion that, like its two-dimensional counterpart, this system exhibits an inverse transfer of magnetic energy that terminates only at the system scale. We perform direct numerical simulations that confirm these predictions and reveal other interesting aspects of the evolution of the system. We find, for example, that the early time evolution is characterized by a sharp decay of the initial magnetic energy, which we attribute to the ubiquitous formation of current sheets. We also show that a quantitatively similar inverse transfer of magnetic energy is observed when the initial condition is a random, small-scale magnetic seed field. |
| first_indexed | 2024-09-23T14:10:25Z |
| format | Article |
| id | mit-1721.1/135457 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T14:10:25Z |
| publishDate | 2021 |
| publisher | Cambridge University Press (CUP) |
| record_format | dspace |
| spelling | mit-1721.1/1354572023-09-13T17:45:26Z Multi-scale dynamics of magnetic flux tubes and inverse magnetic energy transfer Zhou, Muni Loureiro, Nuno F Uzdensky, Dmitri A Massachusetts Institute of Technology. Plasma Science and Fusion Center © 2020 The Author(s). Published by Cambridge University Press. We report on an analytical and numerical study of the dynamics of a three-dimensional array of identical magnetic flux tubes in the reduced-magnetohydrodynamic description of the plasma. We propose that the long-time evolution of this system is dictated by flux-tube mergers, and that such mergers are dynamically constrained by the conservation of the pertinent (ideal) invariants, viz. the magnetic potential and axial fluxes of each tube. We also propose that in the direction perpendicular to the merging plane, flux tubes evolve in a critically balanced fashion. These notions allow us to construct an analytical model for how quantities such as the magnetic energy and the energy-containing scale evolve as functions of time. Of particular importance is the conclusion that, like its two-dimensional counterpart, this system exhibits an inverse transfer of magnetic energy that terminates only at the system scale. We perform direct numerical simulations that confirm these predictions and reveal other interesting aspects of the evolution of the system. We find, for example, that the early time evolution is characterized by a sharp decay of the initial magnetic energy, which we attribute to the ubiquitous formation of current sheets. We also show that a quantitatively similar inverse transfer of magnetic energy is observed when the initial condition is a random, small-scale magnetic seed field. 2021-10-27T20:23:32Z 2021-10-27T20:23:32Z 2020 2021-08-09T18:43:43Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/135457 en 10.1017/S0022377820000641 Journal of Plasma Physics Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf Cambridge University Press (CUP) arXiv |
| spellingShingle | Zhou, Muni Loureiro, Nuno F Uzdensky, Dmitri A Multi-scale dynamics of magnetic flux tubes and inverse magnetic energy transfer |
| title | Multi-scale dynamics of magnetic flux tubes and inverse magnetic energy transfer |
| title_full | Multi-scale dynamics of magnetic flux tubes and inverse magnetic energy transfer |
| title_fullStr | Multi-scale dynamics of magnetic flux tubes and inverse magnetic energy transfer |
| title_full_unstemmed | Multi-scale dynamics of magnetic flux tubes and inverse magnetic energy transfer |
| title_short | Multi-scale dynamics of magnetic flux tubes and inverse magnetic energy transfer |
| title_sort | multi scale dynamics of magnetic flux tubes and inverse magnetic energy transfer |
| url | https://hdl.handle.net/1721.1/135457 |
| work_keys_str_mv | AT zhoumuni multiscaledynamicsofmagneticfluxtubesandinversemagneticenergytransfer AT loureironunof multiscaledynamicsofmagneticfluxtubesandinversemagneticenergytransfer AT uzdenskydmitria multiscaledynamicsofmagneticfluxtubesandinversemagneticenergytransfer |