Filamentary structure on the Sun from the magnetic Rayleigh-Taylor instability
Filamentary structure on the Sun from the magnetic Rayleigh-Taylor instability
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DOI：
10.1038/nature03399
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发表时间：
2005-03-24
期刊：
影响因子：
64.8
通讯作者：
Yokoyama, T
中科院分区：
文献类型：
--
作者：
Isobe, H;Miyagoshi, T;Yokoyama, T
磁通量从太阳表面以暗丝的形式出现，连接极性相反的小太阳黑子（1-3）。暗丝周围的区域在X射线中通常是明亮的，并且与喷流有关（4-6）。这意味着等离子体加热和加速，这对日冕加热很重要。以前对这些区域的二维模拟表明，日冕磁场和新兴通量之间的磁重联产生了X射线喷流和耀斑，但没有解决日冕结构的起源和加热的间歇性。在这里，我们报告了对出射通量的三维模拟，结果表明暗丝结构是由磁性瑞利-泰勒不稳定性自发产生的（7，8），这与以前的观点相反，即暗丝是从携带致密气体的光球层中升起的孤立磁场束（9-11）。由于磁瑞利-泰勒不稳定性，薄电流片形成的新兴通量，和磁重联之间发生新兴通量和预先存在的日冕场在空间上间歇的方式。这自然地解释了日冕加热的间歇性和太阳耀斑中的斑片状增亮。
Magnetic flux emerges from the solar surface as dark filaments connecting small sunspots with opposite polarities(1-3). The regions around the dark filaments are often bright in X-rays and are associated with jets(4-6). This implies plasma heating and acceleration, which are important for coronal heating. Previous two-dimensional simulations of such regions showed that magnetic reconnection between the coronal magnetic field and the emerging flux produced X-ray jets and flares, but left unresolved the origin of filamentary structure and the intermittent nature of the heating. Here we report three-dimensional simulations of emerging flux showing that the filamentary structure arises spontaneously from the magnetic Rayleigh - Taylor instability(7,8), contrary to the previous view that the dark filaments are isolated bundles of magnetic field that rise from the photosphere carrying the dense gas(9-11). As a result of the magnetic Rayleigh - Taylor instability, thin current sheets are formed in the emerging flux, and magnetic reconnection occurs between emerging flux and the pre-existing coronal field in a spatially intermittent way. This explains naturally the intermittent nature of coronal heating and the patchy brightenings in solar flares.