3D MHD simulations of emerging flux and associated reconnection

Hiroaki Isobe, Takehiro Miyagoshi, Kazunari Shibata, and Takaaki Yokoyama

Emerging flux plays important role in the energy accumulation and the trigger of flares and coronal mass ejections. It also has some information of the structure of the magnetic field below the photosphere. Hence it is obviously one of the principal targets of Solar-B observations. We carried out three-dimensional MHD simulations of an emerging flux region with high resolution using the unprecedented computational power of the Earth Simulator, a vector-parallel super computer installed at the Earth Simulator Center. The main results are summarized as follows: (1) Filamentary structure similar to an arch filament system is spontaneously formed in the emerging flux due to the magnetic Rayleigh-Taylor instability. (2) Filamentary current sheets are formed in the emerging flux as a result of the nonlinear development of the magnetic Rayleigh-Taylor instability. This naturally explains the intermittent heating of emerging flux regions observed in EUV images. (3) Magnetic reconnection between the emerging flux and the coronal field occurs in spatially intermittent way, because of the interchanging of the current sheet due to the Rayleigh-Taylor instability.

Correspondence

Hiroaki Isobe (isobe@kwasan.kyoto-u.ac.jp), Department of Earth and Planetary Science, University of Tokyo

presentation

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