Turbulence Diffusion and Energy Spectrum Analysis of Large-scale Current Sheets in Flares |
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| Institution: | 1. Yunnan Astronomical Observatories, Chinese Academy of Sciences, Kunming 650011;2. University of Chinese Academy of Sciences, Beijing 100049;3. Institute of Space Physics, Luoyang Normal University, Luoyang 471934;4. Center for Astronomical Mega-Science, Chinese Academy of Sciences, Beijing 100012;1. Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210023;2. Key Laboratory of Planetary Sciences, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210023;3. School of Astronomy and Space Science, University of Science and Technology of China, Hefei 230026;1. Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030;2. University of Chinese Academy of Sciences, Beijing 100049;3. Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, Nanjing 210023;1. Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210023;2. Key Laboratory foe Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210023;3. School of Astronomy and Space Science, University of Science and Technology of China, Hefei 230026;1. Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030;2. University of Chinese Academy of Sciences, Beijing 100049;1. Yunnan Astronomical Observatories, Chinese Academy of Sciences, Kunming 650011;2. School of Astronomy and Space Science, University of Chinese Academy of Sciences, Beijing 100049;1. National Space Science Center, Chinese Academy of Sciences, Beijing 100190;2. Key Laboratory of Science and Technology on Environmental Space Situation Awareness, Chinese Academy of Sciences, Beijing 100190;3. University of Chinese Academy of Sciences, Beijing 100049 |
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| Abstract: | Magnetic reconnection (MR) is one of the most important physical processes for many dynamical phenomena in the universe. Magnetohydrodynamical (MHD) simulation is an effective way to study the MR process and the physical pictures related to the MR. With different parameter setups, we investigate the influences of the Magnetic Reynolds number and spatial resolution on the reconnection rate, numerical dissipation, and energy spectrum distribution in the MHD simulation. We have found that the magnetic Reynolds number has definite impact on the reconnection rate and energy spectrum distribution. The characteristic time for entering into the non-linear phase will be earlier as the Reynolds number increases. When it comes to the tearing phase, the reconnection rate will increase rapidly. On the other hand, the magnetic Reynolds number affects significantly the Kolmogorov microscopic scale , which becomes smaller as increases. An extra dissipation is defined as the combined effect of the numerical diffusion and turbulence dissipation. It is shown that the extra dissipation is dominated by the numerical diffusion before the tearing mode instability takes place. After the instability develops, the extra dissipation rises vastly, which indicates that turbulence caused by the instability can enhance the diffusion obviously. Furthermore, the energy spectrum analysis indicates that of the large-scale current sheet may appear at a macroscopic MHD scale very possibly. |
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| Keywords: | Sun: magnetic fields Magnetic reconnection Magnetohydrodynamics (MHD) dissipation |
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