Numerical experiments on magnetic reconnection in solar flare and coronal mass ejection current sheets

Authors

  • Z. Mei,

    Corresponding author
    1. Graduate School of the Chinese Academy of Sciences, Beijing, China
    • Yunnan Astronomical Observatory, Chinese Academy of Sciences, Kunming, Yunnan, China
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  • C. Shen,

    1. Yunnan Astronomical Observatory, Chinese Academy of Sciences, Kunming, Yunnan, China
    2. Graduate School of the Chinese Academy of Sciences, Beijing, China
    3. Harvard–Smithsonian Center for Astrophysics, Cambridge, MA, USA
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  • N. Wu,

    1. School of Tourism and Geography, Yunnan Normal University, Kunming, Yunnan, China
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  • J. Lin,

    Corresponding author
    1. Harvard–Smithsonian Center for Astrophysics, Cambridge, MA, USA
    • Yunnan Astronomical Observatory, Chinese Academy of Sciences, Kunming, Yunnan, China
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  • N. A. Murphy,

    1. Harvard–Smithsonian Center for Astrophysics, Cambridge, MA, USA
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  • I. I. Roussev

    1. Yunnan Astronomical Observatory, Chinese Academy of Sciences, Kunming, Yunnan, China
    2. Institute for Astronomy, University of Hawaii, Honolulu, HI, USA
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E-mail: meizhixing@ynao.ac.cn (ZM); jlin@ynao.ac.cn (JL)

ABSTRACT

Magnetic reconnection plays a critical role in energy conversion during solar eruptions. This paper presents a set of magnetohydrodynamic experiments for the magnetic reconnection process in a current sheet (CS) formed in the wake of the rising flux rope. The eruption results from the loss of equilibrium in a magnetic configuration that includes a current-carrying flux rope, representing a pre-existing filament. In order to study the fine structure and micro processes inside the CS, mesh refinement is used to reduce the numerical diffusion. We start with a uniform, explicitly defined resistivity which results in a Lundquist number S = 104 in the vicinity of CS. The use of mesh refinement allows the simulation to capture high-resolution features such as plasmoids from the tearing mode and plasmoid instability regions of turbulence and slow-mode shocks. Inside the CS, magnetic reconnection goes through the Sweet–Parker and the fractal stages, and eventually displays a time-dependent Petschek pattern. Our results support the concept of fractal reconnection suggested by Shibata et al. and Shibata & Tanuma, and also suggest that the CS evolves through Sweet–Parker reconnection prior to the fast reconnection stage. For the first time, the detailed features and/or fine structures inside the coronal mass ejection/flare CS in the eruption were investigated in this work.

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