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Dong C, Wang L, Huang YM, Comisso L, Sandstrom TA, Bhattacharjee A. Reconnection-driven energy cascade in magnetohydrodynamic turbulence. SCIENCE ADVANCES 2022; 8:eabn7627. [PMID: 36475799 PMCID: PMC9728964 DOI: 10.1126/sciadv.abn7627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 10/28/2022] [Indexed: 06/17/2023]
Abstract
Magnetohydrodynamic turbulence regulates the transfer of energy from large to small scales in many astrophysical systems, including the solar atmosphere. We perform three-dimensional magnetohydrodynamic simulations with unprecedentedly large magnetic Reynolds number to reveal how rapid reconnection of magnetic field lines changes the classical paradigm of the turbulent energy cascade. By breaking elongated current sheets into chains of small magnetic flux ropes (or plasmoids), magnetic reconnection leads to a previously undiscovered range of energy cascade, where the rate of energy transfer is controlled by the growth rate of the plasmoids. As a consequence, the turbulent energy spectra steepen and attain a spectral index of -2.2 that is accompanied by changes in the anisotropy of turbulence eddies. The omnipresence of plasmoids and their consequences on, for example, solar coronal heating, can be further explored with current and future spacecraft and telescopes.
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Affiliation(s)
- Chuanfei Dong
- Princeton Plasma Physics Laboratory, Princeton University, Princeton, NJ 08540, USA
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
| | - Liang Wang
- Princeton Plasma Physics Laboratory, Princeton University, Princeton, NJ 08540, USA
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
| | - Yi-Min Huang
- Princeton Plasma Physics Laboratory, Princeton University, Princeton, NJ 08540, USA
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
| | - Luca Comisso
- Department of Astronomy and Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA
| | | | - Amitava Bhattacharjee
- Princeton Plasma Physics Laboratory, Princeton University, Princeton, NJ 08540, USA
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
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Zhao ZH, Xie Y, Lei Z, Jiao JL, Zhou WM, Zhou CT, Zhu SP, He XT, Qiao B. Onset of inverse magnetic energy transfer in collisionless turbulent plasmas. Phys Rev E 2021; 104:025204. [PMID: 34525564 DOI: 10.1103/physreve.104.025204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 07/28/2021] [Indexed: 11/07/2022]
Abstract
Inverse magnetic energy transfer from small to large scales is a key physical process for the origin of large-scale strong magnetic fields in the universe. However, so far, from the magnetohydrodynamic perspective, the onset of inverse transfer is still not fully understood, especially the underlying dynamics. Here, we use both two-dimensional and three-dimensional particle-in-cell simulations to show the self-consistent dynamics of inverse transfer in collisionless decaying turbulent plasmas. Using the space filtering technique in theory and numerical analyses, we identify magnetic reconnection as the onset and fundamental drive for inverse transfer, where, specifically, the subscale electromotive force driven by magnetic reconnection do work on the large-scale magnetic field, resulting in energy transfer from small to large scales. The mechanism is also verified by the strong correlations in locations and characteristic scales between inverse transfer and magnetic reconnection.
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Affiliation(s)
- Z H Zhao
- Center for Applied Physics and Technology, HEDPS, and SKLNPT, School of Physics, Peking University, Beijing 100871, China
| | - Y Xie
- Center for Applied Physics and Technology, HEDPS, and SKLNPT, School of Physics, Peking University, Beijing 100871, China
| | - Z Lei
- Center for Applied Physics and Technology, HEDPS, and SKLNPT, School of Physics, Peking University, Beijing 100871, China
| | - J L Jiao
- Center for Applied Physics and Technology, HEDPS, and SKLNPT, School of Physics, Peking University, Beijing 100871, China
| | - W M Zhou
- Science and Technology on Plasma Physics Laboratory, Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China
| | - C T Zhou
- Center for Advanced Material Diagnostic Technology, Shenzhen Technology University, Shenzhen 518118, China
| | - S P Zhu
- Institute of Applied Physics and Computational Mathematics, Beijing 100094, China
| | - X T He
- Center for Applied Physics and Technology, HEDPS, and SKLNPT, School of Physics, Peking University, Beijing 100871, China.,Institute of Applied Physics and Computational Mathematics, Beijing 100094, China
| | - B Qiao
- Center for Applied Physics and Technology, HEDPS, and SKLNPT, School of Physics, Peking University, Beijing 100871, China
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Comisso L, Sironi L. Particle Acceleration in Relativistic Plasma Turbulence. PHYSICAL REVIEW LETTERS 2018; 121:255101. [PMID: 30608827 DOI: 10.1103/physrevlett.121.255101] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 11/14/2018] [Indexed: 06/09/2023]
Abstract
Due to its ubiquitous presence, turbulence is often invoked to explain the origin of nonthermal particles in astrophysical sources of high-energy emission. With particle-in-cell simulations, we study decaying turbulence in magnetically dominated (or, equivalently, "relativistic") pair plasmas. We find that the generation of a power-law particle energy spectrum is a generic by-product of relativistic turbulence. The power-law slope is harder for higher magnetizations and stronger turbulence levels. In large systems, the slope attains an asymptotic, system-size-independent value, while the high-energy spectral cutoff increases linearly with system size; both the slope and the cutoff do not depend on the dimensionality of our domain. By following a large sample of particles, we show that particle injection happens at reconnecting current sheets; the injected particles are then further accelerated by stochastic interactions with turbulent fluctuations. Our results have important implications for the origin of nonthermal particles in high-energy astrophysical sources.
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Affiliation(s)
- Luca Comisso
- Department of Astronomy and Columbia Astrophysics Laboratory, Columbia University, New York, New York 10027, USA
| | - Lorenzo Sironi
- Department of Astronomy and Columbia Astrophysics Laboratory, Columbia University, New York, New York 10027, USA
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